机械类毕业设计英文翻译

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机械专业毕业设计外文翻译----高速铣削

英文资料High-speed millingHigh-speed machining is an advanced manufacturing technology, different from the traditional processing methods. The spindle speed, cutting feed rate, cutting a small amount of units within the time of removal of material has increased three to six times. With high efficiency, high precision and high quality surface as the basic characteristics of the automobile industry, aerospace, mold manufacturing and instrumentation industry, such as access to a wide range of applications, has made significant economic benefits, is the contemporary importance of advanced manufacturing technology. For a long time, people die on the processing has been using a grinding or milling EDM (EDM) processing, grinding, polishing methods. Although the high hardness of the EDM machine parts, but the lower the productivity of its application is limited. With the development of high-speed processing technology, used to replace high-speed cutting, grinding and polishing process to die processing has become possible. To shorten the processing cycle, processing and reliable quality assurance, lower processing costs.1 One of the advantages of high-speed machiningHigh-speed machining as a die-efficient manufacturing, high-quality, low power consumption in an advanced manufacturing technology. In conventional machining in a series of problems has plagued by high-speed machining of the application have been resolved.1.1 Increase productivityHigh-speed cutting of the spindle speed, feed rate compared withtraditional machining, in the nature of the leap, the metal removal rate increased 30 percent to 40 percent, cutting force reduced by 30 percent, the cutting tool life increased by 70% . Hardened parts can be processed, a fixture in many parts to be completed rough, semi-finishing and fine, and all other processes, the complex can reach parts of the surface quality requirements, thus increasing the processing productivity and competitiveness of products in the market.1.2 Improve processing accuracy and surface qualityHigh-speed machines generally have high rigidity and precision, and other characteristics, processing, cutting the depth of small, fast and feed, cutting force low, the workpiece to reduce heat distortion, and high precision machining, surface roughness small. Milling will be no high-speed processing and milling marks the surface so that the parts greatly enhance the quality of the surface. Processing Aluminum when up Ra0.40.6um, pieces of steel processing at up to Ra0.2 ~ 0.4um.1.3 Cutting reduce the heatBecause the main axis milling machine high-speed rotation, cutting a shallow cutting, and feed very quickly, and the blade length of the workpiece contacts and contact time is very short, a decrease of blades and parts of the heat conduction. High-speed cutting by dry milling or oil cooked up absolute (mist) lubrication system, to avoid the traditional processing tool in contact with the workpiece and a lot of shortcomings to ensure that the tool is not high temperature under the conditions of work, extended tool life.1.4 This is conducive to processing thin-walled partsHigh-speed cutting of small cutting force, a higher degree of stability, Machinable with high-quality employees compared to the company may be very good, but other than the company's employees may Suanbu Le outstanding work performance. For our China practice, we use the models to determine the method of staff training needs are simple and effective. This study models can be an external object, it can also be a combination of internal and external. We must first clear strategy for the development of enterprises. Through the internal and external business environment and organizational resources, such as analysis, the future development of a clear business goals and operational priorities. According to the business development strategy can be compared to find the business models, through a comparative analysis of the finalization of business models. In determining business models, a, is the understanding of its development strategy, or its market share and market growth rate, or the staff of the situation, and so on, according to the companies to determine the actual situation. As enterprises in different period of development, its focus is different, which means that enterprises need to invest the manpower and financial resources the focus is different. So in a certain period of time, enterprises should accurately selected their business models compared with the departments and posts, so more practical significance, because the business models are not always good, but to compare some aspects did not have much practical significance, Furthermore This can more fully concentrate on the business use of limited resources. Identify business models, and then take the enterprise of the corresponding departments and staff with the business models for comparison, the two can be found in the performance gap, a comparative analysis to find reasons, in accordance with this business reality, the final identification of training needs. The cost of training is needed, if not through an effective way to determine whether companies need to train and the training of the way, but blind to training, such training is difficult to achieve the desired results. A comparison only difference between this model is simple and practical training.1.5 Can be part of some alternative technology, such as EDM, grinding high intensity and high hardness processingHigh-speed cutting a major feature of high-speed cutting machine has the hardness of HRC60 parts. With the use of coated carbide cutter mold processing, directly to the installation of ahardened tool steel processing forming, effectively avoid the installation of several parts of the fixture error and improve the parts of the geometric location accuracy. In the mold of traditional processing, heat treatment hardening of the workpiece required EDM, high-speed machining replace the traditional method of cutting the processing, manufacturing process possible to omit die in EDM, simplifying the processing technology and investment costs .High-speed milling in the precincts of CNC machine tools, or for processing centre, also in the installation of high-speed spindle on the general machine tools. The latter not only has the processing capacity of general machine tools, but also for high-speed milling, a decrease of investment in equipment, machine tools increased flexibility. Cutting high-speed processing can improve the efficiency, quality improvement, streamline processes, investment and machine tool investment and maintenance costs rise, but comprehensive, can significantly increase economic efficiency.2 High-speed millingHigh-speed milling the main technical high-speed cutting technology is cutting the development direction of one of it with CNC technology, microelectronic technology, new materials and new technology, such as technology development to a higher level. High-speed machine tools and high-speed tool to achieve high-speed cutting is the prerequisite and basic conditions, in high-speed machining in the performance of high-speed machine tool material of choice and there are strict requirements.2.1 High-speed milling machine in order to achieve high-speed machiningGeneral use of highly flexible high-speed CNC machine tools, machining centers, and some use a dedicated high-speed milling, drilling. At the same time a high-speed machine tool spindle system and high-speed feeding system, high stiffness of the main characteristics of high-precision targeting and high-precision interpolation functions, especially high-precision arc interpolation function. High-speed machining systems of the machine a higher demand, mainly in the following areas:General use of highly flexible high-speed CNC machine tools, machining centers, and some use a dedicated high-speed milling, drilling. At the same time a high-speed machine tool spindle system and high-speed feeding system, high stiffness of the main characteristics of high-precision targeting and high-precision interpolation functions, especially high-precision arc interpolation function. High-speed machining systems of the machine a higher demand, mainly in the following areas:High-speed milling machine must have a high-speed spindle, the spindle speed is generally 10000 ~ 100000 m / min, power greater than 15 kW. But also with rapid speed or in designated spots fast-stopping performance. The main axial space not more than 0 .0 0 0 2 m m. Often using high-speed spindle-hydrostatic bearings, air pressure-bearing, mixed ceramic bearings, magneticbearing structure of the form. Spindle cooling general use within the water or air cooled.High-speed processing machine-driven system should be able to provide 40 ~ 60 m / min of the feed rate, with good acceleration characteristics, can provide 0.4 m/s2 to 10 m/s2 acceleration and deceleration. In order to obtain good processing quality, high-speed cutting machines must have a high enough stiffness. Machine bed material used gray iron, can also add a high-damping base of concrete, to prevent cutting tool chatter affect the quality of processing. A high-speed data transfer rate, can automatically increase slowdown. Processing technology to improve the processing and cutting tool life. At present high-speed machine tool manufacturers, usually in the general machine tools on low speed, the feed of the rough and then proceed to heat treatment, the last in the high-speed machine on the half-finished and finished, in improving the accuracy and efficiency at the same time, as far as possible to reduce processing Cost.2.2 High-speed machining toolHigh-speed machining tool is the most active one of the important factors, it has a direct impact on the efficiency of processing, manufacturing costs and product processing and accuracy. Tool in high-speed processing to bear high temperature, high pressure, friction, shock and vibration, such as loading, its hardness and wear-resistance, strength and toughness, heat resistance, technology and economic performance of the basic high-speed processing performance is the key One of the factors. High-speed cutting tool technology development speed, the more applications such as diamond (PCD), cubic boron nitride (CBN), ceramic knives, carbide coating, (C) titanium nitride Carbide TIC (N) And so on. CBN has high hardness, abrasion resistance and the extremely good thermal conductivity, and iron group elements between the great inertia, in 1300 ℃ would not have happened significant role in the chemical, also has a good stability. The experiments show that with CBN cutting toolHRC35 ~ 67 hardness of hardened steel can achieve very high speed. Ceramics have good wear resistance and thermal chemical stability, its hardness, toughness below the CBN, can be used for processing hardness of HRC <5 0 parts. Carbide Tool good wear resistance, but the hardness than the low-CBN and ceramics. Coating technology used knives, cutting tools can improve hardness and cutting the rate, for cutting HRC40 ~ 50 in hardness between the workpiece. Can be used to heat-resistant alloys, titanium alloys, hightemperature alloy, cast iron, Chungang, aluminum and composite materials of high-speed cutting Cut, the most widely used. Precision machining non-ferrous metals or non-metallic materials, or the choice of polycrystalline diamond Gang-coated tool.2.3 High-speed processing technologyHigh-speed cutting technology for high-speed machining is the key. Cutting Methods misconduct, will increase wear tool to less than high-speed processing purposes. Only high-speed machine tool and not a good guide technology, high-speed machining equipment can not fullyplay its role. In high-speed machining, should be chosen with milling, when the milling cutter involvement with the workpiece chip thickness as the greatest, and then gradually decreased. High-speed machining suitable for shallow depth of cut, cutting depth of not more than 0.2 mm, to avoid the location of deviation tool to ensure that the geometric precision machining parts. Ensure that the workpiece on the cutting constant load, to get good processing quality. Cutting a single high-speed milling path-cutting mode, try not to interrupt the process and cutting tool path, reducing the involvement tool to cut the number to be relatively stable cutting process. Tool to reduce the rapid change to, in other words when the NC machine tools must cease immediately, or Jiangsu, and then implement the next step. As the machine tool acceleration restrictions, easy to cause a waste of time, and exigency stop or radical move would damage the surface accuracy. In the mold of high-speed finishing, in each Cut, cut to the workpiece, the feed should try to change the direction of a curve or arc adapter, avoid a straight line adapter to maintain the smooth process of cutting.3 Die in high-speed milling processing ofMilling as a highly efficient high-speed cutting of the new method,inMould Manufacturing has been widely used. Forging links in the regular production model, with EDM cavity to be 12 ~ 15 h, electrodes produced 2 h. Milling after the switch to high-speed, high-speed milling cutter on the hardness of HRC 6 0 hardened tool steel processing. The forging die processing only 3 h20min, improve work efficiency four to five times the processing surface roughness of Ra0.5 ~ 0.6m, fully in line with quality requirements.High-speed cutting technology is cutting technology one of the major developments, mainly used in automobile industry and die industry, particularly in the processing complex surface, the workpiece itself or knives rigid requirements of the higher processing areas, is a range of advanced processing technology The integration, high efficiency and high quality for the people respected. It not only involves high-speed processing technology, but also including high-speed processing machine tools, numerical control system, high-speed cutting tools and CAD / CAM technology. Die-processing technology has been developed in the mold of the manufacturing sector in general, and in my application and the application of the standards have yet to be improved, because of its traditional processing with unparalleled advantages, the future will continue to be an inevitable development of processing technology Direction.4 Numerical control technology and equipping development trend and countermeasureEquip the engineering level, level of determining the whole national economy of the modernized degree and modernized degree of industry, numerical control technology is it develop new developing new high-tech industry and most advanced industry to equip (such as information technology and his industry, biotechnology and his industry, aviation, spaceflight, etc. national defense industry) last technology and getting more basic most equipment. Marx has ever said "the differences of different economic times, do not lie in what is produced, and lie in how to produce,produce with some means of labor ". Manufacturing technology and equipping the most basic means of production that are that the mankind produced the activity, and numerical control technology is nowadays advanced manufacturing technology and equips the most central technology. Nowadays the manufacturing industry all around the world adopts numerical control technology extensively, in order to improve manufacturing capacity and level, improve the adaptive capacity and competitive power to the changeable market of the trends. In addition every industrially developed country in the world also classifies the technology and numerical control equipment of numerical control as the strategic materials of the country, not merely take the great measure to develop one's own numerical control technology and industry, and implement blockading and restrictive policy to our country in view of " high-grade, precision and advanced key technology of numerical control " and equipping. In a word, develop the advanced manufacturing technology taking numerical control technology as the core and already become every world developed country and accelerate economic development in a more cost-effective manner, important way to improve the overall national strength and national position. Numerical control technology is the technology controlled to mechanical movement and working course with digital information, integrated products of electromechanics that the numerical control equipment is the new technology represented by numerical control technology forms to the manufacture industry of the tradition and infiltration of the new developing manufacturing industry, namely the so-called digitization is equipped, its technological range covers a lot of fields: (1)Mechanical manufacturing technology; (2)Information processing, processing, transmission technology; (3)Automatic control technology; (4)Servo drive technology;(5)Technology of the sensor; (6)Software engineering ,etc..Development trend of a numerical control technologyThe application of numerical control technology has not only brought the revolutionary change to manufacturing industry of the tradition, make the manufacturing industry become the industrialized symbol , and with the constant development of numerical control technology and enlargement of the application, the development of some important trades (IT , automobile , light industry , medical treatment ,etc. ) to the national economy and the people's livelihood of his plays a more and more important role, because the digitization that these trades needed to equip has already been the main trend of modern development. Numerical control technology in the world at present and equipping the development trend to see, there is the following several respect [1- ] in its main research focus.5 A high-speed, high finish machining technology and new trend equippedThe efficiency, quality are subjavanufacturing technology. High-speed, high finish machining technology can raise the efficiency greatly , improve the quality and grade of the products, shorten production cycle and improve the market competitive power. Japan carries the technological research association first to classify it as one of the 5 great modern manufacturing technologies forthis, learn (CIRP) to confirm it as the centre in the 21st century and study one of the directions in international production engineering.In the field of car industry, produce one second when beat such as production of 300,000 / vehicle per year, and many variety process it is car that equip key problem that must be solved one of; In the fields of aviation and aerospace industry, spare parts of its processing are mostly the thin wall and thin muscle, rigidity is very bad, the material is aluminium or aluminium alloy, only in a situation that cut the speed and cut strength very small high, could process these muscles, walls. Adopt large-scale whole aluminium alloy method that blank " pay empty " make the wing recently, such large-scale parts as the fuselage ,etc. come to substitute a lot of parts to assemble through numerous rivet , screw and other connection way, make the intensity , rigidity and dependability of the component improved. All these, to processing and equipping the demand which has proposed high-speed, high precise and high flexibility.According to EMO2001 exhibition situation, high-speed machining center is it give speed can reach 80m/min is even high , air transport competent speed can up to 100m/min to be about to enter. A lot of automobile factories in the world at present, including Shanghai General Motors Corporation of our country, have already adopted and substituted and made the lathe up with the production line part that the high-speed machining center makes up. HyperMach lathe of U.S.A. CINCINNATI Company enters to nearly biggest 60m/min of speed, it is 100m/min to be fast, the acceleration reaches 2g, the rotational speed of the main shaft has already reached 60 000r/min. Processing a thin wall of plane parts, spend 30min only, and same part general at a high speed milling machine process and take 3h, the ordinary milling machine is being processed to need 8h; The speed and acceleration of main shaft of dual main shaft lathes of Germany DMG Company are up to 120000r/mm and 1g.In machining accuracy, the past 10 years, ordinary progression accuse of machining accuracy of lathe bring 5μm up to from 10μm already, accurate grades of machining center from 3～5μm, rise to 1～1.5μm, and ultraprecision machining accuracy is i t enter nanometer grade to begin already (0.01μm).In dependability, MTBF value of the foreign numerical control device has already reached above 6 000h, MTBF value of the servo system reaches above 30000h, demonstrate very high dependability .In order to realize high-speed, high finish machining, if the part of function related to it is electric main shaft, straight line electrical machinery get fast development, the application is expanded further .5.2 Link and process and compound to process the fast development of the lathe in 5 axesAdopt 5 axles to link the processing of the three-dimensional curved surface part, can cut with the best geometry form of the cutter , not only highly polished, but also efficiency improves by a large margin . It is generally acknowledged, the efficiency of an 5 axle gear beds can equal 2 3 axle gearbeds, is it wait for to use the cubic nitrogen boron the milling cutter of ultra hard material is milled and pared at a high speed while quenching the hard steel part, 5 axles link and process 3 constant axles to link and process and give play to higher benefit. Because such reasons as complicated that 5 axles link the numerical control system , host computer structure that but go over, it is several times higher that its price links the numerical control lathe than 3 axles , in addition the technological degree of difficulty of programming is relatively great, have restricted the development of 5 axle gear beds.At present because of electric appearance of main shaft, is it realize 5 axle complex main shaft hair structure processed to link greatly simplify to make, it makes degree of difficulty and reducing by a large margin of the cost, the price disparity of the numerical control system shrinks. So promoted 5 axle gear beds of head of complex main shaft and compound to process the development of the lathe (process the lathe including 5).At EMO2001 exhibition, new Japanese 5 of worker machine process lathe adopt complex main shaft hair, can realize the processing of 4 vertical planes and processing of the wanton angle, make 5 times process and 5 axles are processed and can be realized on the same lathe, can also realize the inclined plane and pour the processing of the hole of awls. Germany DMG Company exhibits the DMUVoution series machining center, but put and insert and put processing and 5 axles 5 times to link and process in once, can be controlled by CNC system or CAD/CAM is controlled directly or indirectly.5.3 Become the main trend of systematic development of contemporary numerical control intelligently, openly, networkedly.The numerical control equipment in the 21st century will be sure the intelligent system, the intelligent content includes all respects in the numerical control system: It is intelligent in order to pursue the efficiency of processing and process quality, control such as the self-adaptation of the processing course, the craft parameter is produced automatically; Join the convenient one in order to improve the performance of urging and use intelligently, if feedforward control , adaptive operation , electrical machinery of parameter , discern load select models , since exactly makes etc. automatically; The ones that simplified programming , simplified operating aspect are intelligent, for instance intelligent automatic programming , intelligent man-machine interface ,etc.; There are content of intelligence diagnose , intelligent monitoring , diagnosis convenient to be systematic and maintaining ,etc..Produce the existing problem for the industrialization of solving the traditional numerical control system sealing and numerical control application software. A lot of countries carry on research to the open numerical control system at present, such as NGC of U.S.A. (The Next Generation Work-Station/Machine Control), OSACA of European Community (Open System Architecture for Control within Automation Systems), OSEC (Open System Environment for Controller) of Japan, ONC (Open Numerical Control System) of China, etc.. The numerical control system melts tobecome the future way of the numerical control system open. The so-called open numerical control system is the development of the numerical control system can be on unified operation platform, face the lathe producer and end user, through changing, increasing or cutting out the structure target(numerical control function), form the serration, and can use users specially conveniently and the technical know-how is integrated in the control system, realize the open numerical control system of different variety , different grade fast, form leading brand products with distinct distinction. System structure norm of the open numerical control system at present, communication norm , disposing norm , operation platform , numerical control systematic function storehouse and numerical control systematic function software development ,etc. are the core of present research.The networked numerical control equipment is a new light spot of the fair of the internationally famous lathe in the past two years. Meeting production line , manufacture system , demand for the information integration of manufacturing company networkedly greatly of numerical control equipment, realize new manufacture mode such as quick make , fictitious enterprise , basic Entrance that the whole world make too. Some domestic and international famous numerical control lathes and systematic manufacturing companies of numerical control have all introduced relevant new concepts and protons of a machine in the past two years, if in EMO2001 exhibition, " Cyber Production Center " that the company exhibits of mountain rugged campstool gram in Japan (Mazak) (intellectual central production control unit, abbreviated as CPC); The lathe company of Japanese big Wei (Okuma ) exhibits " IT plaza " (the information technology square , is abbreviated as IT square ); Open Manufacturing Environment that the company exhibits of German Siemens (Siemens ) (open the manufacturing environment, abbreviated as OME),etc., have reflected numerical control machine tooling to the development trend of networked direction.5.4 Pay attention to the new technical standard, normal setting-up5.4.1 Design the norm of developing about the numerical control systemAs noted previously, there are better common ability, flexibility, adaptability, expanding in the open numerical control system, such countries as U.S.A. ,European Community and Japan ,etc. implement the strategic development plan one after another , carry on the research and formulation of the systematic norm (OMAC , OSACA , OSEC ) of numerical control of the open system structure, 3 biggest economies in the world have carried on the formulation that nearly the same science planned and standardized in a short time, have indicated a new arrival of period of change of numerical control technology. Our country started the research and formulation of standardizing the frame of ONC numerical control system of China too in 2000.5.4.2 About the numerical control standardThe numerical control standard is a kind of trend of information-based development of manufacturing industry. Information exchange among 50 years after numerical control technology was born was all because of ISO6983 standard, namely adopt G, M code describes how processes,。

机械毕业设计英文外文翻译116电动平衡叉车

附录ATray selection and with the shelves, forklift matchFirst, the selected tray Size:When used plastic pallets, according to the requirements of the project, the selected size will be different.1. First, consider the specifications and packaging of goods placed in the plastic tray method. For example: the European standard turnover box size is 600 * 400mm, 1200 * 1000mm pallet in place a layer of 5 in 1200 * 800mm layer placed on the tray 4, the general stacking 5 layers.2. Consider the pallet loading tools (such as containers, trucks, etc.). For example: If you are working round-trip or one-time use, you need to give priority to the width of 2300mm of integrated container shipping, for 1200 * 1000mm pallet, length 1200mm and width 1000mm to use a combination of place, must be selected to enter the fork 4. The tray on the 1200 * 800mm, 800mm width direction with two side by side. The pallet of 1100 * 1100mm width by 1100mm, placed 2, 2, or 4 to enter the fork into the fork can be.3. If used in the warehouse shelves, shelves to consider the size of width and depth, usually select the shelves each placed two trays of each cargo space, and allow access to the space of about 200mm. In depth directionas far as possible to give large size, this does not produce plastic pallets carrying capacity of the stringent requirements in order to save procurement costs.4. If the use of automated warehouse shelves, in addition to meet the above requirements, but also take into account the slip coefficient of the tray, the tray bottom with transmission equipment and chain, into the fork height, carrying capacity on the shelves, permanent deformation, length of surface deflection, the position of bar coding and RFID chips placed on other factors.5. Use plastic trays should also consider the size of generality, the size of the domestic common international standard for the 1210, 1208 European standard and T11 Japanese standard tray.Second, the choice of single and double-sided:1. Single use plastic pallets only one side, the surface grid of two peace-plate, the bottom of Sichuan fonts, font, or nine square field pad feet, according to carrying capacity and the use of different occasions into shelf series, standard series and ultra-light series of three standards.2. Sided plastic tray that the same structure on both sides of the tray, the surface grid plate of peace are two sides to exchange used, based on carrying capacity and the use of different occasions, the shelves are divided into two series and standard series standards.3. Use double-sided tray or trays should be based on the appropriatestorage, loading and unloading equipment and state (such as the library type, rack type, stacking or placing the state, etc.) to determine.4. For the small footprint of the ASRS or high shelves, or electric stacker forklift to move vertically oriented occasion, single-sided double-sided shelf series shelf series of trays and trays can be chosen.5. If the three-dimensional library or load up on the shelves of 1T, but there is no ceiling shelves, the proposed shelf tray with built-in pipe. Steel structure steel tray built an effective solution to the product on the shelf load the greater the greater the weight, the old problem of high cost, more importantly, about the use of square steel tube wall thickness of 2mm rigid, reaching the shelves (ASRS) are horizontal and vertical deflection ≤ 10mm stringent requirements, while reducing the permanent deformation and reduce costs.6. For the area, mainly the large and the level of the occasion, if the manual handling hydraulic pallet truck is suitable for use single-sided tray. For stacking of goods to the bottom of the tray above and below the cargo coincide, the swastika with the end of double-sided tray or tray-type side is better. If using self-moving motorized pallet trucks are suitable for articles not connected with the bottom of the nine feet single tray.Third, the load requirements1. Dynamic load refers to the use of electric forklift or a manual hydraulicpallet truck can lift the maximum weight allowed. General shelf tray to load-bearing 1.5T-2T, the standard load-bearing pallet can 1T, lightweight tray dynamic load 0.5T.2. Static load refers to the stacking, the bottom of the plastic tray can bear maximum weight. General shelf tray to load-bearing 6T-8T, the standard load-bearing pallet can 4T, lightweight tray static 1T.3. Shelf load refers to the plastic tray packaging on the shelves when the maximum allowable weight. Must pay attention to dynamic load, static load, load library shelf load and establish the difference between carrying capacity and shelves of different structures, closely related to ambient temperature and storage period. General heavy trays on a shelf in load-bearing beams 0.7T-1T, standard tray loading 0.4T-0.6T.4. Shelf load permanent deformation of the plastic tray and deflection have certain requirements, national standards for the maximum deflection 30mm, but this was partial width. We recommend using the deflection on the shelf no more than 20mm of plastic pallets. If the automatic warehouse, the requirements of the degree of deflection even more stringent, generally require less than 10mm. Cheng Machinery silver mesh)附录B电动平衡叉车是以直流电源（电瓶）为动力的装卸及搬运车辆。

机械专业毕业设计外文翻译12

Development of a high-performance laser-guided deep-holeboring tool: optimal determination of reference origin for precise guidingAbstractA laser-guided deep-hole boring tool using piezoelectric actuators was developed to prevent hole deviation. To extend the depth o controll able boring further, the following were improved. The tool’s guiding error, caused by misalignment of the corner cube prism and the mirror in the optical head from the spindle axis, was eliminated using an adjustment jig that determined the reference origins of the two position-sensitive detectors (PSDs) precisely. A single-edge counter-boring head is used instead of the double-edge head used up to now The former was thought to be better in attitude control than the latter. A new boring bar, which was lower in rigidity and better in Controllability of tool attitude, was used. Experiments were conducted to examine the performance of the new tool in detail and to determin its practical application, using duralumin (A2017-T4) workpieces with a prebored 108-mm diameter hole. The experiments were performed with a rotating tool–stationary workpiece system. Rotational speed was 270 rpm and feed was 0.125 mm/rev. Tool diameter was 110 mm Asaresult,controlled boring becomes possible up to a depth of 700 mm under the stated experimental conditions.700 mm is the maximum machinable length of the machine tool. The tool can be put to practical use.Keywords: Deep hole-boring; Adaptive control; Laser application1.IntroductionTo bore a precise straight hole, a deep-hole boring tool should be guided toward a target. From this point of view, the laser-guided deep-hole boring tool was developed [1–6]. The latest tool using piezoelectric actuators could be guided to go straight toward the target,despitedisturbances up to a depth of 388 mm [6].In the present paper, before the performance of the tool is examined, the following points are improved to extend the depth. The tool’s guiding error, caused by misalignment of the corner cube prism and the mirror in the optical head from the spindle axis, is eliminated using a jig that deter- mines the reference origins of the two position-sensitive detectors (PSDs) precisely. A single-edge counter-boring head is used instead of the double-edge head used up to now. The former is thought to be better in attitude control than the latter. A new boring bar, which is 15% lower in both bending and torsional rigidity and which is better in controllability of tool attitude, is used.2. Experimental apparatusFigs. 1 and 2 show the tool head and the experimental apparatus, respectively [6]. The head is the same as that used in experiments up to now. One cutting edge of the double-edge counter-boring head is replaced by a guide pad,And six guide pads are removed[4].By removal of the guide pads, cutting oil is supplied better between the other guide pads and hole wall. The tool head consists of an optical head, a counter-boring head, piezoelectric actuators, and an actuator holder (Fig. 1). The optical head is attached to the front surface of the counter-boring head through an adjust- ment jig. The actuator holder is connected to a rotation stopper 14 behind the tool head by two parallel plates of phosphor bronze 6 (Fig. 2). A laser source 11, and PSDs 9, 10 are set in front of the tool. The rectangular coordinates XAnd Y are set on a plane perpendicular to the spindle rotation axis(Z-axis).The optical distancebetween a dichroic mirror in the optical head and PSD 10 for measuring tool inclina- tion is 2,040 mm [2].3. Method for detection of tool position and its inclinationFig. 3 shows the method used for measuring the tool position and its inclination. The laser beam, radiated from an argon laser, reaches the dichroic mirror 6 through the beam expander 5 and the half mirror 1. The dichroic mirror separates the two beams of wavelengths 514 nm (green) and 488 nm (blue). The green beam for measuring tool position passes through the dichroic mirror 6 and reachesthe corner cube prism 8. The reflected beam passes again through 6 and is deflected by the half mirror 1 toward dichroic mirror 2. By passing through the dichroic mirror 2, it reaches the PSD 9 used for measuring tool position. The blue beam for measuring tool inclination reaches the dichroic mirror 7 with an angle of incidence equal to 0°. The dichroic mirror 7 reflects the blue beam and trans- mits parts of the green beam, which are not completelyseparated by the dichroic mirror 6. The returning beam from the dichroic mirror 7 is deflected by the mirrors 6, 1, and 2, then passing through the dichroic mirror 4, and reaches the PSD 10 for measuring tool inclination. Re- flective characteristics of dichroic mirror 4 differs from that of dichroic mirror 7.4. Acquisition of data for controlling the toolData for tool attitude control are acquired from the two PSDs for tool position and its inclination every rotation of the counter-boring head. Until now, outputs of the two PSDs (measuring tool position and its inclination) some- times did not correspond well to the measured hole devia- tion. To determine what causes this, the following is exam- ined. The tool head with the optical head is supported by two V-blocks and is aligned on the Z-axis at the same longitudinal position as in the experiment. Then, the laser beam is radiated, and the optical head is rotated manually.Fig. 4 shows variations of outputs of two PSDs with encoder pulse during one rotation of the optical head fixed on the counter-boring head. Theoretically, outputs of two PSDs are constant during one rotation of the optical head corresponding to a 1,400 pulse of output of an encoder. Changes of X- and Y-outputs of tool position are caused by change of darkness of the laser spot because of interference and polarization of the laser beam. Changes of X- and Y- outputs of tool inclination are caused by inclination of the reflecting mirror in the optical head from the Z-axis. From the last experiment [6] on, tool position and its inclination are measured at rotational pulse position 700, where the brightness of the two PSDs are preferable at the same time.5. Misalignment of the optical parts in the optical headEven if the laser source and the PSDs for tool position and its inclination are aligned on Z-axis, hole deviation appeared. To discover its cause, the misalignment of the corner cube prism and inclination of reflecting mirror in the optical head from the Z-axis are examined.Fig. 5 shows all cases of alignment errors. Fig. 5(a) shows that the corner cube prism and the reflecting mirror are precisely aligned on the Z-axis. Figs. 5(b) and 5(c) are, the cases in which the corner cube prism is displaced by and the reflecting mirror is inclined byfrom the Z-axis, respectively.IncaseofFig.5(d),errorsofFigs.5(b)and(c) occur together. Fig. 5(e) shows the case when the optical head is inclined byduring the setup of the counter-boring head. Fig. 5(f) is the worst case, when all errors occur together. These errors cannot be eliminated by conventional adjustment. Therefore a new guiding strategy is developed to ensure that the tool can be guided straight, even if errors should occur.6. Optimal setup of reference origin for precise guidingFig. 6 shows the optimal setup method of reference origins. The laser source is aligned on the Z-axis [Fig. 6(a)] [6]. The optical head is fixed to the front surface of a cylindrical alignment jig through an adjustment jig. The alignment jig is inserted into the guide bush, which is fixed on a machine table, and the centers of both alignment jig and the optical head are aligned on Z-axis. Then the laser beam is radiated. Reflected beams reach the PSDs for tool position and its inclination. When the cylinder is rotated by hand, the rotational position, at which the output is most reliable, can be found. Next, the PSDs are moved until the spots lie at their centers. This position corresponds to the pulse position 700 of the encoder. The centers are reference origins for tool position and its inclination.At this rotational position,the optical head is fixed to the counter-boring head using the adjustment jig [Fig.6(b)].When the control starts, the tool head follows the alignment jig’s axis.7. Mechanism of tool displacementFig. 7 shows the mechanism of tool displacement. Fig. 7(a) shows the normal cutting condition [7]. The cutting force P is acting on the cutting edge and is counterbalanced by the guide pads. Fig. 7(b) shows the case where the tool is to correct for a deviation. A chain double-dashed line shows the hole wall before correction of hole deviation. A Directed line shows the direction of the correction.When the tool is controlled to incline toward the direction of the directed line, a cutting edge set ahead of the guide pads overcuts the hole wall. When the guide pad on the opposite side comes to the position of the overcutting zone, the cutting edge leaves a noncutting zone on the hole wall Opposite the overcutting zone.As a result,tool shifts toward the direction of the directed line.In the case of double-edge counter-boring head, the cut- ting force acting on one cutting edge is balanced by the force that acts on the other cutting edge [7]. As a result, the head is easy to vibrate, and the mechanism of tool displace- ment does not function well.Form: Precision Engineering 24 (2000) 9–14 开发高性能的激光制导deep-holeboring工具：最佳测定参考来源精确指导摘要激光制导深孔钻具使用压电致动器是防止孔偏差。

机械自动化类毕业设计外文翻译--电子设计自动化

附录B 翻译原文Electronic design automation Keyword EDA; IC;VHDL language; FPGAPROCESS DESCRIPTIONThree obstacles in particular bedevil ic designers in this dawn of the system on a chip. The first is actually a shortfall-the hardware and software components of the design lack a unifying language. Then, as the number of logic gates per chip passes the million marks, verification of a design's correctness is fast becoming more arduous than doing the design itself. And finally, not only gate counts but chip frequencies also are climbing, so that getting a design to meet its timing requirements without too many design iterations is a receding goal.As is the wont of the electronic design automation (EDA) community, these concerns are being attacked by start-up companies led by a few individuals with big ideas and a little seed money. PARLEZ-VOUS SUPERLOG?A system on a chip comprises both circuitry and the software that runs on it. Such a device may contain an embedded processor core running a software modem. Most often, after the chip'sfunctionality is spelled out, usually on paper, the hardware com- potent is handed off to the circuit designers and the software is given to the pro- grammars, to meet up again at some later date.The part of the chips functionality that will end up as logic gates and transistors is writ- ten in a hardware design language-Virology or VHDL, while the part that will end up as software is most often described in the programming language C or C++. The use of these disparate languages hampers the ability to describe, model, and debug the circuitry of the IC and the software in a coherent fashion.It is time, many in the industry believe, for a new design language that can cope with both hardware and software from the initial design specification right through to final verification. Just such a new language has been developed by Co-Design Automation Inc., San Jose, Calif.Before launching such an ambitious enterprise, cofounders Simon Davidmann, who is also chief operating officer, and Peter Flake ruled out the usefulness of extending an existing language to meet system-on-chip needs. Among the candidates for extension were C, C++, Java, and Verilog.A design language should satisfy three requirements, maintained Davidmann. It should unify the design process. It should make designing more efficient. And it should evolve out of an existing methodology. None of the existing approaches filled the bill. So Davidmann and Flake set about developing new co-design language called Superlog.A natural starting point was a blend of Virology and C since "from an algorithm point of view, a lot of Virology is built on C," explained Davidmann. Then they spiced the blend with bits and pieces of VHDL and Java. From Virology and VHDL, Superlog has acquired the ability to describe hardware aspects of the design, such as sequential, combinatorial, and multivalued logic. From C and Java it inherits dynamic processes and other software constructs. Even functions like interfaces, protocols, and state machines, which till now have often been done on paper, can be described in the new language. To support legacy code written in a hardware description or programming language, Superlog allows both Virology and C modules to be imported and used directly.It is important for the language to be in the public domain, according to Davidmann. The company has already begun to work with various standards organizations to this end.Not to be overlooked is the need for a suite of design tools based on the language. Recently Co-Design identified a number of electronic design automation companies, among them Magma Design Automation, Sente, and Viewlogic, that will develop tools based on Superlog. Co-Design will also develop products for the front end of the design process.ARACE TO THE FINISHNot everyone is convinced that a new language is needed. SystemC, a modeling platform that extends the capabilities andadvantages of C/C++ into the hardware domain has been proposed as an alternative. Such large and powerful companies as Synopsys, Coware, Lucent Technologies, and Texas Instruments have banded together under the Open SystemC Initiative to promote their version of the next-generation design platform. To get SystemC off to a running start, the group offers a modeling platform for download off their Web site free of charge. Their hope is also to make their platform the de facto standard.The rationale for developing SystemC was straightforward, according to Joachim Kunkel, general manager and vice president of the System Level Design Business Unit at Synopsys. It was to have a standard language in which semiconductor vendors, IP vendors, and system houses could exchange system-level IP and executable specifications, and the electronic design automation industry could develop interoperable tools.Supporters of SystemC believe that the would-be standard has to be based on C++ because it allows capabilities to be added to it without leaving the language standard, Kunkel told JEEE Spectrum. Most software developers use C++ and many systems developers use C++ already to describe their systems at a behavioral level. But till now it has not been possible to describe hardware using the language.The developers of SystemC have solved that problem by defining new C++ class libraries and a simulation kcrne1 that bring to C++ all of the capabilities needed to describe hardware. "These new classes implement new functionality," explained Kunkel. "Forexample, bit vectors-strings of zeros and ones-and all the operations that you would do on them." The SystemC developers also provided a class of signed and unsigned numbers, the notion of a signal, and other concepts needed to model hardware.There are still some holes, however. For example, it is still not possible to synthesize a gate-level netlist from a SystcmC description. Rut synthesis tools for SysteniC would he a natural result of broad acceptance of the language within the user community, according to Kunkel.It remains to be seen whether SystemC or Superlog wins out in the end. Least desirable would be an outcome like the impasse between Virology and VHDL, in which both prevailed, forcing electronic design automation vendors to support both platforms in a wasteful duplication of effort.THE VERIFICATION NIGHTMAREIf today's complex ICs are tough to design, they are very much tougher to verify. A variety of tools are available, each with its pros and cons. Emulation translates a design into field-programmable gate arrays (FPGAs). Presumably, if the array works as planned, the final chip will also. The emulation platform also enables designers to try 0111 the software that will run on the ASIC.The approach, though, is slow. Typical emulation systems run at a few megahertz. "At roughly one million cycles per second, designers arc not getting cnough performance out of their emulation systems toverify or understand some of the things that are going on with video generation or high bandwidth communications," said John Gallagher, director of marketing for Synplicity Inc., Sunnyvale, Calif. They must process a large number of operations to ensure their functionality is correct, he added.The reason that emulation systems are so slow, according to Gallagher, is that they route the design through many FPGAs and many boards. Simplicity solution is to use a few high-end FPGAs having over one million gates running at 100 MHz. Typically, a million FPGA gates translates into 200 000 ASIC gates. Putting nine such chips on a board in a three-by-three array allows designers to represent up to 1.8million ASlC gates. And routing delays are greatly curtailed because each chip is no more than two hops away from any other chip in the array.The company% product, called Certify, is not intended to compete with reconfigurable emulation systems, which are very effective at debugging designs during the internal design process, explained Gallagher. Rather, it is a true prototype of the system, running at speeds that may approach the real thing.Certify handles three fundamental operations, said Gallagher. The first is partitioning, or breakings up the ASIC register transfer level (RTL) code into different FPGAs. It does synthesis, turning the RTL code into ASIC gates equivalent to the final ASIC gates. Then it does timing analysis. "We haven't just linked togeth er the different tools,” he explained. 'We have taka our synthesis algorithms, between thepartitioning capabilities, and laid the timing analysis across that."In addition to emulation, two complementary approaches to design verification are simulation and model checking, a type of formal verification. Simulation applies vectors to a software model of a design and checks to sec if the output has the correct value. The approach is straightforward, but is becoming increasingly tortuous as designs become more complicated and the number of possible test vectors mushrooms. So recently, electronic design automation companies have been turning to model checking to prove that designs are correctly done.The sticking point with model checking is its great difficulty of use. "It is not for most engineers," said Simon Napper, chief operating officer OF Innol-ogic Systems Inc., San Jose, Calif. "The usage model is very difficult-it checks properties. But the designer isn't familiar with what P property is-he is used to simulation and static timing."As a remedy, InnoLogic developed a symbolic simulation tool, which blends simulation and formal verification. It is a Virology simulator except instead of sending Is and Os through the logic, the too1 propagates symbol or symbols plus binary values.The user gains improved functional coverage dong with much faster verification.To illustrate, to completely verify a fourbit adder would require 256 binary vectors-and take 256 simulation cycles. With symbols, it takes just one cycle.Just as with formal verification, there are limits to the complexity ofthe circuits that symbolic simulation can completely verily. Both have trouble with multipliers, for example. "A model checker will grind and grind and never produce a result," explained Napper. "But in our tool we take some symbol inputs and switch them to binary values, that reduces the job from a 32- to a 16-bit multiplier. And we report to the user that we were able to verify the upper the operands."InnoLogic has announced two Versifies of symbolic simulation. ESI'-XV verifies designs written in Virology. EXP-CV is meant for custom designs and memory blocks.THE TIME IS RIGHTThough the design of ICs with semiconductor geometries below 0.25 pm face challenges throughout development, some of the biggest hurdles occur during physical design, when the gates are placed on the chip and the interconnects are routed between them Problems occur here for a number of reasons. First, the capacitance, resistance, and inductance of the interconnects cannot be ignored, as they were in older, larger technologies. Crosstalk between interconnects; now closer together, must also be controlled. Several iterations through synthesis and placement may be necessary to achieve the required timing, if it can be accomplished at all.The solution proposed by Monterey Design Systems Inc., Sunnyvale, Calif., is called global design technology. This proprietary computing approach simultaneously explores, analyzes, and optimizes all aspects of the physical design. The tint productcontaining the technology is Dolphin, which was announced in April of last year. Dolphin simultaneously places and router each gate and flip-flop using the results or the analysis and maintaining all specified constraints. (Most place- and-route tools sequentially analyze the layout for each type of constraint.) It performs timing and logic optimization for every placement move.Timing closure is top priority for developers of the Blast Fusion physical design system from Magma Design Automations., Cupertino, Calif. Its methodology, called FixedTiming, brings timing within specified limits without iterating between synthesis and physical design .Basically, he approach fixes timing first, then adjusts cell sizes to achieve the timing requirements. Varying the cell sizes always he tool to supply the right drive strength or the load.EDA ON THE WEBAs established electronic design automation companies try to sort out how to utilize the internet in their product Inks, smaller, more agile companies and start-ups arc coining up with innovative products and services, mainly in the areas or design management. A pioneer in this area is Synchronicity Inc., a virtual company headquartered in Marlboro, Mass. Synchronicity is now being joined by other companies seeking to use the internet to advantage.The concern of , Milpitas, Calif a provider of Web-based engineering tools 'for; design automation, is the extraction of useful information about ICs, chip sets, and boards from suppliers'Web sites.The issue, according to Michael Bitzko, president of the company, is that designers of products based on there components need to be able to obtain information about them quickly and route it to their engineering, manufacturing, and procurement departments as quickly as possible. "In a nutshell,” said Bitzko, "people used to take weeks to get data sheets. Then along cane the Web and PDF-formatted documents. But in order to create, ray, schematic symbols and footprints fur printed circuit boards, information from PDF documents must often be reentered-a costly and time-consuming process when time to infarct is a concern.'s products are based on the electronic component interchange (ECIX) standard developed by EDA standards organization SI, Austin, Texas, and on the Extensible Markup Language (XML), that allows the creation or Web-bask documents having (more functionality than with the conventional Hypertext Markup Language (H TM1.). The company’s products include QuickData Server, a parametric search engine for electronic component information, and Quickdata Miner, which transform information contained in PDF data sheets into a usable form.The mission or Genedax Inc., Portland, Ore. is to use the Web to increase designed ability to create and manage large, complex designs, to iron design ICLISC, and to improve access to intellectual property. The company plans to announce a product in the first quarter or the year. John Ott, vice president of sales and marketing,told Sprctmni that its products will be based on the operating systems and browsers developed by Microsott Corp., Redmond, Wash. Also, the company supports a collaborative Web site, that shows what the technology can do. The site includes a search engine based on AltaVista technology that searches the Web sites of companies related to design auto illation. Ott elaborated, "We also have a free Internet locator server that lets people use Netmeeting a Microsoft product for remote sharing of computer desktops] and a Web board where you can post questions and get answers."Other aspects of electronic design on the Webs have been slower in taking off than design and information management. But Transim Corp also bared in Portland, Ore, has taken a big step toward Web-based design tools. Its product, Websim, is an interface between a Web browser and Simples, the company’s power-supply simulator. Websim allows designers, using Simplis, to simulate designs over the Internet. So rather than poring over data sheets and looking at ranges of values, designers can see actual waveforms, explained Ncls Gahbert, Transim president and chief executive officer.Transim is working with suppliers to set up component models so that designers can log on to the supplies Web rite, select parts for their power supply, enter setup or test conditions, and run the simulation on line. Users need nothing more than a Web browser. The simulation is run on Transim's "ranch" of six strivers from Sun Microsystems.The company has teamed up with National Semiconductor Corp, Santa Clara, Calif., to provide this service for National's customers. The cost is on a per-use basis and is a minimal US $10.附录C 翻译中文电子设计自动化关键字电子设计自动化；集成电路；VHDL语言；现场可编程门阵列在这个片上系统开始出现的时候，有三个问题一直困扰着集成电路设计者。

机械专业毕业设计外文翻译10

翻译部分英文部分ADV ANCED MACHINING PROCESSESAs the hardware of an advanced technology becomes more complex, new and visionary approaches to the processing of materials into useful products come into common use. This has been the trend in machining processes in recent years.. Advanced methods of machine control as well as completely different methods of shaping materials have permitted the mechanical designer to proceed in directions that would have been totally impossible only a few years ago.Parallel development in other technologies such as electronics and computers have made available to the machine tool designer methods and processes that can permit a machine tool to far exceed the capabilities of the most experienced machinist.In this section we will look at CNC machining using chip-making cutting tools. CNC controllers are used to drive and control a great variety of machines and mechanisms, Some examples would be routers in wood working; lasers, plasma-arc, flame cutting, and waterjets for cutting of steel plate; and controlling of robots in manufacturing and assembly. This section is only an overview and cannot take the place of a programming manual for a specific machine tool. Because of the tremendous growth in numbers and capability of comp uters ,changes in machine controls are rapidly and constantly taking place. The exciting part of this evolution in machine controls is that programming becomeseasier with each new advanced in this technology.Advantages of Numerical ControlA manually operated machine tool may have the same physical characteristics as a CNC machine, such as size and horsepower. The principles of metal removal are the same. The big gain comes from the computer controlling the machining axes movements. CNC-controlled machine tools can be as simple as a 2-axis drilling machining center (Figure O-1). With a dual spindle machining center, the low RPM, high horsepower spindle gives high metal removal rates. The high RPM spindle allows the efficient use of high cutting speed tools such as diamonds and small diameter cutters (Figure O-2). The cutting tools that remove materials are standard tools such as milling cutters, drills, boring tools, or lathe tools depending on the type of machine used. Cutting speeds and feeds need to be correct as in any other machining operation. The greatest advantage in CNC machining comes from the unerring and rapid positioning movements possible. A CNC machine does dot stop at the end of a cut to plan its next move; it does not get fatigued; it is capable of uninterrupted machining error free, hour after hour. A machine tool is productive only while it is making chips.Since the chip-making process is controlled by the proper feeds and speeds, time savings can be achieved by faster rapid feed rates. Rapid feeds have increased from 60 to 200 to 400 and are now often approaching 1000 inches per minute (IPM). These high feed rates can pose a safety hazard to anyone within the working envelope of the machine tool.Complex contoured shapes were extremely difficult to product prior to CNC machining .CNC has made the machining of these shapes economically feasible. Design changes on a part are relatively easy to make by changing the program that directs the machine tool.A CNC machine produces parts with high dimensional accuracy and close tolerances without taking extra time or special precautions, CNC machines generally need less complex work-holding fixtures, which saves time by getting the parts machined sooner. Once a program is ready and production parts, each part will take exactly the same amount of time as the previous one. This repeatability allows for a very precise control of production costs. Another advantage of CNC machining is the elimination of large inventories; parts can be machined as needs .In conventional production often a great number of parts must be made at the same time to be cost effective. With CNC even one piece can be machined economically .In many instances, a CNC machine can perform in one setup the same operations that would require several conventional machines.With modern CNC machine tools a trained machinist can program and product even a single part economically .CNC machine tools are used in small and large machining facilities and range in size from tabletop models to huge machining centers. In a facility with many CNC tools, programming is usually done by CNC programmers away from the CNC tools. The machine control unit (MCU) on the machine is then used mostly for small program changes or corrections. Manufacturing with CNC tools usually requires three categories of persons. The first is the programmer, who is responsible for developing machine-ready code. The next person involved is the setup person, who loads the raw stork into the MCU, checks that the co rrect tools are loaded, and makes the first part. The third person is the machine and unloads the finished parts. In a small company, one person is expected to perform all three of these tasks.CNC controls are generally divided into two basic categories. One uses a ward address format with coded inputs such as G and M codes. The other users a conversational input; conversational input is also called user-friendly or prompted input. Later in this section examples of each of these programming formats in machining applications will be describes.CAM and CNCCAM systems have changed the job of the CNC programmer from one manually producing CNC code to one maximizing the output of CNC machines. Since CNC machine tools are made by a great number of manufacturers, many different CNC control units are in use. Control units from different manufacturers use a variety of program formats and codes. Many CNC code words are identical for different controllers, but a great number vary from one to another.To produce an identical part on CNC machine tools with different controllers such as one by FANCU, OKUMA or DYNAPATH, would require completely different CNC codes. Each manufacturer is constantly improving and updating its CNC controllers. These improvements often include additional code words plus changes in how the existing code works.A CAM systems allows the CNC programmer to concentrate on the creation of an efficient machining process, rather then relearning changed code formats. A CNC programmer looks atthe print of a part and then plans the sequence of machining operations necessary to make it (Figure O-3). This plan includes everything, from the selection of possible CNC machine tools, to which tooling to use, to how the part is held while machining takes place. The CNC programmer has to have a thorough understanding of all the capacities and limitations of the CNC machine tools that a program is to be made for. Machine specifications such as horsepower, maximum spindle speeds, workpiece weight and size limitations, and tool changer capacity are just some of the considerations that affect programming.Another area of major importance to the programmer is the knowledge of machining processes. An example would be the selection of the surface finish requirement specified in the part print. The sequence of machining processes is critical to obtain acceptable results. Cutting tool limitations have to be considered and this requires knowledge of cutting tool materials, tool types, and application recommendations.A good programmer will spend a considerable amount of time in researching the rapidly growing volume of new and improved tools and tool materials. Often the tool that was on the cutting edge of technology just two years ago is now obsolete. Information on new tools can come from catalogs or tool manufacturers' tooling engineers. Help in tool selection or optimum tool working conditions can also be obtained from tool manufacturer software. Examples would be Kennametal's "TOOLPRO", software designed to help select the best tool grade, speed, and feed rates for different work materials in turning application. Another very important feature of "TOOLPRO" is the display of the horsepower requirement for each machining selection. This allow the programmer to select a combination of cutting speed, feed rate, and depth of cut that equals the machine's maximum horsepower for roughing cuts. For a finishing cut, the smallest diameter of the part being machined is selected and then the cutting speed varied until the RPM is equal to the maximum RPM of the machine. This helps in maximizing machining efficiency. Knowing the horsepower requirement for a cut is critical if more than one tool is cutting at the same time.Software for a machining center application would be Ingersoll Tool Company's "Actual Chip Thickness", a program used to calculate the chip thickness in relation to feed-per-tooth for a milling cutter, especially during a shallow finishing cut. Ingersoll's "Rigidity Analysis" software ealculates tool deflection for end mills as a function of tool stiffness and tool force.To this point we looked at some general qualifications that a programmer should possess. Now we examine how a CAM system works. Point Control Company's SmartCam system uses the following approach. First, the programmer makes a mental model of the part to be machined. This includes the kind of machining to be performed-turning or milling. Then the part print is studied to develop a machining sequence, roughing and finishing cuts, drilling, tapping, and boring operations. What work-holding device is to be used, a vise or fixture or clamps? After these considerations, computer input can be started. First comes the creation of a JOBPLAN. This JOBPLAN consists of entries such as inch or metric units, machine type, part ID, type of workpiece material, setup notes, and a description of the required tools.This line of information describes the tool by number, type, and size and includes theappropriate cutting speed and feed rate. After all the selected tools are entered, the file is saved.The second programming step is the making of the part. This represents a graphic modeling of the projected machining operation. After selecting a tool from the prepared JOBPLAN, parameters for the cutting operation are entered. For a drill, once the coordinate location of the hole and the depth are given, a circle appears on that spot. If the location is incorrect, the UNDO command erases this entry and allows you to give new values for this operation. When an end mill is being used, cutting movements (toolpath) are usually defined as lines and arcs. As a line is programmed, the toolpath is graphically displayed and errors can be corrected instantly.At any time during programming, the command SHOWPATH will show the actual toolpath for each of the programmed tools. The tools will be displayed in the sequence in which they will be used during actual machining. If the sequence of a tool movement needs to be changed, a few keystrokes will to that.Sometimes in CAM the programming sequence is different from the actual machining order. An example would be the machining of a pocket in a part. With CAM, the finished pocket outline is programmed first, then this outline is used to define the ro ughing cuts to machine the pocket. The roughing cuts are computer generated from inputs such as depth and width of cut and how much material to leave for the finish cut. Different roughing patterns can be tried out to allow the programmer to select the most efllcient one for the actual machining cuts. Since each tool is represented by a different color, it is easy to observe the toolpath made by each one.A CAM system lets the programmer view the graphics model from varying angles, such as a top, front, side, or isometric view. A toolpath that looks correct from a top view, may show from a front view that the depth of the cutting tool is incorrect. Changes can easily be made and seen immediately.When the toolpath and the sequence of operations are satisfactory, machine ready code has to be made. This is as easy as specifying the CNC machine that is to be used to machine the part. The code generator for that specific CNC machin e during processing accesses four different files. The JOBPLAN file for the tool information and the GRAPHICE file for the toolpath and cutting sequence. It also uses the MACHINE DEFINE file which defines the CNC code words for that specific machine. This file also supplies data for maximum feed rates, RPM, toolchange times, and so on. The fourth file taking part in the code generating process is the TEMPLATE file. This file acts like a ruler that produces the CNC code with all of its parts in the right place and sequence. When the code generation is complete, a projected machining time is displayed. This time is calculated from values such as feed rates and distances traveled, noncutting movements at maximum feed rates between points, tool change times, and so on. The projected machining time can be revised by changing tooling to allow for higher metal removal rates or creating a more efficient toolpath. This display of total time required can also be used to estimate production costs. If more then one CNC machine tool is available to machine this part, making code and comparing the machining time may show that one machine is more efficient than the others.CAD/CAMAnother method of creating toolpath is with the use of a Computer-aided Drafting (CAD) file. Most machine drawings are created using computers with the description and part geometry stored in the computer database. SmartCAM, though its CAM CONNECTION, will read a CAD file and transfer its geometry represents the part profile, holes, and so on. The programmer still needs to prepare a JOBPLAN with all the necessary tools, but instead of programming a profile line by line, now only a tool has to be assigned to an existing profile. Again, using the SHOWPA TH function will display the toolpath for each tool and their sequence. Constant research and developments in CAD/CAM interaction will change how they work with each other. Some CAD and CAM programs, if loaded on the same computer, make it possible to switch between the two with a few keystrokes, designing and programming at the same time.The work area around the machine needs to be kept clean and clear of obstructions to prevent slipping or tripping. Machine surfaces should not be used as worktables. Use proper lifting methods to handle heavy workpieces, fixtures, or heavy cutting tools. Make measurements only when the spindle has come to a complete standstill. Chips should never be handled with bare hands.Before starting the machine make sure that the work-holding device and the workpiece are securely fastened. When changing cutting tools, protect the workpiece being machined from damage, and protect your hands from sharp cutting edges. Use only sharp cutting tools. Check that cutting tools are installed correctly and securely.Do not operate any machine controls unless you understand their function and what the y will do.The Early Development Of Numerically Controlled Machine ToolsThe highly sophisticated CNC machine tools of today, in the vast and diverse range found throughout the field of manufacturing processing, started from very humble beginnings in a number of the major industrialized countries. Some of the earliest research and development work in this field was completed in USA and a mention will be made of the UK's contribution to this numerical control development.A major problem occurred just after the Second World War, in that progress in all areas of military and commercial development had been so rapid that the levels of automation and accuracy required by the modern industrialized world could not be attained from the lab our intensive machines in use at that time. The question was how to overcome the disadvantages of conventional plant and current manning levels. It is generally ackonwledged that the earliest work into numerical control was the study commissioned in 1947 by the US governme nt. The study's conclusion was that the metal cutting industry throughout the entire country could not copy with the demands of the American Air Force, let alone the rest of industry! As a direct result of the survey, the US Air Force contracted the Persons Corporation to see if they could develop a flexible, dynamic, manufacturing system which would maximize productivity. TheMassachusetts Institute of Technology (MIT) was sub-contracted into this research and development by the Parsons Corporation, during the period 1949-1951,and jointly they developed the first control system which could be adapted to a wide range of machine tools. The Cincinnati Machine Tool Company converted one of their standard 28 inch "Hydro-Tel" milling machines or a three-axis automatic milling made use of a servo-mechanism for the drive system on the axes. This machine made use of a servomechanism for the drive system on the axes, which controlled the table positioning, cross-slide and spindle head. The machine cab be classified as the first truly three axis continuous path machine tool and it was able to generate a required shape, or curve, by simultaneous slide way motions, if necessary.At about the same times as these American advances in machine tool control were taking Place, Alfred Herbert Limited in the United Kingdom had their first Mutinous path control system which became available in 1956.Over the next few years in both the USA and Europe, further development work occurred. These early numerical control developments were principally for the aerospace industry, where it was necessary to cut complex geometric shapes such as airframe components and turbine blades. In parallel with this development of sophisticated control systems for aerospace requirements, a point-to-point controller was developed for more general machining applications. These less sophisticated point-to-point machines were considerably cheaper than their more complex continuous path cousins and were used when only positional accuracy was necessary. As an example of point-to-point motion on a machine tool for drilling operations, the typical movement might be fast traverse of the work piece under the drill's position-after drilling the hole, anther rapid move takes place to the next hole's position-after retraction of the drill. Of course, the rapid motion of the slideways could be achieved by each axis in a sequential and independent manner, or simultaneously. If a separate control was utilisec for each axis, the former method of table travel was less esse ntial to avoid any backlash in the system to obtain the required degree of positional accuracy and so it was necessary that the approach direction to the next point was always the same.The earliest examples of these cheaper point-to-point machines usually did not use recalculating ball screws; this meant that the motions would be sluggish, and sliderways would inevitably suffer from backlash, but more will be said about this topic later in the chapter.The early NC machines were, in the main, based upon a modified milling machine with this concept of control being utilized on turning, punching, grinding and a whole host of other machine tools later. Towards the end of the 1950s,hydrostatic slideways were often incorporated for machine tools of highly precision, which to sonic extent overcame the section problem associated with conventional slideway response, whiles averaging-out slideway inaccuracy brought about a much increased preasion in the machine tool and improved their control characteristics allows "concept of the machining center" was the product of this early work, as it allowed the machine to manufacture a range of components using a wide variety of machining processes at a single set-up, without transfer of workpieces to other variety machine tools. A machining center differed conceptually in its design from that of a milling machine, In that thecutting tools could be changed automatically by the transfer machanism, or selector, from the magazine to spindle, or vice versa.In this ductively and the automatic tool changing feature enabled the machining center to productively and efficiently machine a range of components, by replacing old tools for new, or reselecting the next cutter whilst the current machining process is in cycle.In the mid 1960s,a UK company, Molins, introduced their unique "System 24" which was meant represent the ability of a system to machine for 24 hours per day. It could be thought of as a "machining complex" which allowed a series of NC single purpose machine tools to be linked by a computerized conveyor system. This conveyor allowed the work pieces to be palletized and then directed to as machine tool as necessary. This was an early, but admirable, attempt at a form of Flexible manufacturing System concept, but was unfortunately doomed to failure. Its principal weakness was that only a small proportion of component varieties could be machine at any instant and that even fewer work pieces required the same operations to be performed on them. These factors meant that the utilization level was low, coupled to the fact that the machine tools were expensive and allowed frequent production bottlenecks of work-in-progress to arise, which further slowed down the whole operation.The early to mid-1970s was a time of revolutionary in the area of machine tool controller development, when the term computerized numerical control (CNC) became a reality. This new breed of controllers gave a company the ability to change work piece geometries, together with programs, easily with the minimum of development and lead time, allowing it to be economically viable to machine small batches, or even one-off successfully. The dream of allowing a computerized numerical controller the flexibility and ease of program editing in a production environment became a reality when two ralated factors occurred.These were:the development of integrated circuits, which reduces electronics circuit size, giving better maintenance and allowing more standardization of desing; that general purpose computers were reduced in size coupled to the fact that their cost of production had fallen considerably.The multipie benefits of cheaper electorics with greater reliability have result in the CNC fitted to the machine tools today, with the power and sophistication progtessing considerably in the last few years, allowing an almost artificial intelligence(AI) to the latest systems. Over the years, the machine tools builders have produced a large diversity in the range of applications of CNC and just some of those development will be reviewed in V olume Ⅲ。

机械专业毕业设计英文文献翻译

英文原文Study of Inherent Safety Mine hoist based on modern designmethodsYang Lijie 1, Meng Xiangyun2,Wang Guimei1,Niu Qingna11 Hebei University of Engineering, Handan, Hebei, 056038, ChinaYanglijie255@2 China Telecom Handan Company, Handan, Hebei, 056038, China Abstract—As a modern security design, Inherent Safety means that equipment and facilities is able to contain the inherent fundamental features to prevent accidents. Mine hoist is the most important equipment in the coal production. How to achieve safe, reliable, efficient production has been the focus study at home and abroad. Inherent safety is reflected in hoist design, primarily through the design measures to improve the operation of hoist safety and reliability. In this paper, Inherent Safety theory is applied in the design of mine hoist, to proposed the design method by using the software of PRO/E PLC, Labview etc..Keywords-Mine hoist; Inherent Safety; PRO/E; PLC; LabviewI. INTRODUCTIONIn coal production, mine hoist is the equipment to carry coal, gangue, materials, workers and equipments along the rockshaft, the only way linked underground and aboveground, known as mine throat. Mine hoist is a large-scale reciprocating machinery which has the feature of own big inertia, load changes, running speed, and wide range et al.. The advantages and disadvantages of its operating performance, not only directly affect the normal production and coal production efficiency, but also relate to equipment and personal safety. In recent years, mine hoist failures and accidents have happened at home and abroad which have paid a heavy price to coal companies. Therefore, the production technology and safety of mine hoist are higher, and its mechanical manufacturing technology and electrical control technology has been an important research area to the international machine building industry and the electric control industry.Inherent Safety means that equipment and facilities is able to contain the inherent fundamental features to prevent accidents. Inherent Safety lies in design, through continuous improvement, to prevent accidents due to the equipment itself failures. Inherent safety is reflected in hoist design, primarily through the design measures to improve the operation of hoist safety and reliability. In this paper, Inherent Safety theory is applied in the design of mine hoist, to proposed the inherent safety design method by use the software of PRO/E PLC, Labview etc..II. INHERENT SAFETY THEORYThe term of inherent safety originates the development of world space technology in the 1950s. The concept is widely accepted closely linked with scientific technological progress and human understanding of safety culture. The concept of inherent safety produced after the World War II which became major safety concept in many industrialized countries since the mid 20th century.Inherent safety design as the basic method of hazard control, by selecting safe materials, process routes, mechanical equipment, devices, to eliminate or control hazards source rather than relying on "additional" security measures or management measures to control them. As inherent safety design, firstly analyze and identify hazards that may occur in system, and then choose the best methods to eliminate, control hazards, which reflected in project design.Ⅲ. THE DESIGN OF INHERENT SAFETY MINE HOISTMine hoist mainly includs the working device, control system, transmission system and drag, protection systems and other components. To the inherent safety mine hoist design, mainly the mechanical system, control system and monitor system is the major part to considered.A.In-depth investigations to find malfunctionThe concept of inherent safety is required safety all the time in the product design process. That is, the equipment has little malfunction as much as possible during the operation and has long normal operation cycle length. How can design inherent safety equipment, the most important thing is understanding enough to the equipment, especially in work. After in-depth research, fully understanding the situation, try the best to reduce or eliminate the fault in the design. After in-depth understanding of research, design product.B. Mechanical SystemThe traditional method of product has long design cycle, high costs. However, the virtual prototype technology has the advantage in saving the design cost, shortening the design circle, by using the method of modeling, simulation first and then builds the physical prototype. Therefore, the virtual design is the developing trends of mechanical design. In mechanical system design, the application of virtual prototype is used to design mine hoist, not only speeded up the design process, also simulated a variety of conditions to the virtual prototype to discover design faults, to improve the design, to improve mine hoist performance.Mine hoist mechanical system is composed of spindle, roller, reducer, motor, brakes and other components. In its design, virtual design software PRO / E is applied to establish hoist prototype, application of simulation software ADAMS is used to simulate and optimize the design. Specific process shown in Figure 1:Figure 1. Mechanical system designC. Control system designMine hoist control system includes start, run, brake, etc., the requirements in control system are:In normal hoist operation, participation in hoist speed control, brake the hoist when reaching the destination, known as the service braking;In case of emergency, can quickly slow down as required, brake hoist, to prevent the expansion of the accident, that is the safety braking; Participate in the hoist speed control when decelerati; To double-roller hoist, should brake the moving roller and fix roller respectively when regulating rope length, replacement level and changing rope, so that, moving roller would not move when spindle rotates with the fixed roller.Most of mine hoists in China (more than 70%) use the traditional electric control system (tkd-a as the representative). Tkd control system is composed of relay logic circuits, large air contactors, tachometer generator etc., which is a touch control system. After years of development, tkd-a series of electric control system has formed its own characteristics, but its shortcomings are obvious. Its electrical circuit is too complicated, multi-line, causing hoist parking and accidents occurred due to electrical fault. With the computer and digital technology, to form a digital hoist control systemof PLC has become possible. PLC control system has high control precision, parameter stability, simple hardware structure, self-diagnostic capability and communication networking function.Mine hoist control system based on PLC technology structure shown in Figure 2, mainly including the following components: the main plc control circuits, hoist route detection and display circuits, speed detection, and signal circuits. The PLC of the main control circuits uses Mitsubishi FX2N series in Japan which more domestic applications.Figure 2 PLC electric control systemD. Monitoring system designTo ensure safe operation of the hoist, except for selecting the reasonable operation design parameters, the use of advanced control system, should also monitor the technological parameters on regular, conscientiously do performance test work to master the hoist performance, discover the defects in time, eliminate hidden danger,avoid unnecessary losses. In addition, the hoist operation state can be improved to work in the best conditions based on test data. Therefore, the hoist could work safely, reliably, have high efficiency, and extend its work life.Virtual instrument technology is computer-based instrumentation and measurement technology, is loaded some software and hardware on the computer with similar appearance and performance of the actual independent instrument. The user operating the computer, like manipulating a especially conventional electronic devices designed theirs. The essence of virtual instrument technology is that hardware softwarized technology, take full advantage of the latest computer technology to implement and expand the functions of traditional instruments.LabVIEW (laboratory virtual instrument engineering workbench) is a graphical programming and development environment, also known as "G" language. It is widely used by industry, academia and research laboratories, accepted as the standard data acquisition and instrument control software. LabVIEW not only provides and complies with all the functions of hardware and data acquisition cards communications of GPIB, VXI, RS-232 and RS-485 protocol, and built-in library functions support for TCP / IP, ActiveX and other software standards. The software for scientists and engineers is a programming language, it provides a simple, intuitive graphical programming mode, saves a lot of development time, has complete function, best embodied style of virtual instrument.In response to these circumstances, developed a mine hoist Integrate Performance Monitoring System based on virtual instrument LabVIEW-based. Show in Figure 3. With signal conditioning and data acquisition card to receive signals from sensors, then sent the received signal to the virtual instrument software platform, enables the following features:（1）show speed, acceleration, braking time, displacement, oil pressure, delay time and other relevant parameters in digital, and display speed, acceleration, traction, displacement and hydraulic curves.（2）Dynamically monitor the hydraulic oil pressure and oil pump running station, based on these parameters to avoid important braking system failure.（3）Test brake air travel time, relay delay time and other time parameters.（4）inquiry to the measured curve and hoist parameters; print a test report.Figure 3. Diagram of test systemThe monitoring system has characteristics such as compact, light weight, high precision, testing convenient and flexible, feature-rich software etc.. the system can not only display automatically test results, but also finish multiple functions, for example , data transmission, analysis, processing, storage and report printing. The system is high precision, can easily monitor the hoist operation state, to ensure the reliability of hoist operation.Ⅳ. CONCLUSIONSIn this paper, used virtual design software to design the hoist mechanical system, PLC to design control system, applied virtual instrument software-LABVIEW to design monitor system. Therefore, the mine hoist designed has good mechanical properties and safe operation, monitoring easy.REFERENCES[1] Weng qishu. The inherent safety and checks of cabin[J]. navigationTechnology 2006 (3):50-52. (in Chinese)[2] Li jangbo. Study of Test System of Composite Characteristic of Devices Based onVirtual instrument[D]. A Dissertation Submitted to Hebei University ofEngineering For the Academic Degree of Master of Engineering, 2007. (inChinese)[3] Wang chengqin, Li wei , Meng baoxing et al... Random vibration testing system ofhoisting gear based on virtual instrument. Coal mine machinery, 2008(4) :118-120.(in Chinese)[4] Chen baozhi Wu min. concept and practices of inherent safety[J]. Journal ofSafety Science and Technology,2008(6):79-83. (in Chinese)[5] Xu chenyi, Wu yongdong, Huanghe et al.. A PLC-based mine hoist control systemdesign [J]. LC&FA, 2008(10):52-56 (in Chinese)中文译文基于现代设计方法的矿井提升机内在安全性的研究Yang Lijie 1, Meng Xiangyun2,Wang Guimei1,Niu Qingna11河北工程大学,河北邯郸,056038,中国Yanglijie255@2中国电信邯郸分公司,河北邯郸,056038,中国摘要：作为一个现代的安全设计，内在的安全性意味着设备和设施能够包含防止事故发生的固有基本特征。

机械毕业设计中英翻译

英语原文：CAD/CAM is the technical expression, indicates the computer-aided design and the computer aided manufacturing.This is one item in the design and the production, carries out certain function technology about the use computer data.This technology is completing the design and the production direction to the place develops.In these two traditions was considered is in the production process out of the ordinary, independent function.In brief, CAD/CAM will be able to provide the technology base for the future complete computer production.Looked from the computer science angle that, the design and the manufacture process is one has, processing, the exchange and the management process about the product information.The people use the computer to take the main technical method, from forms in one's mind to the product to put in the market in the entire process information to carry on the analysis and processing, produces and utilizes each kind of numerical information and the graph information, carries on the product the design and the manufacture.The CAD/CAM technology is not the traditional design, the manufacture flow method simple reflection, also is not limits in the partial use computer takes the tool in the individual step or the link, but is unifies the computer science and the project domain specialized technology as well as human's wisdom and the experience take the modern scientific method as the instruction, in the design, in the manufacture entire process each completely manager, as far as possible use computer system completes the work which these duplication high, the labor big, the computation complex as well as depends on purely artificially completes with difficulty, but assists must replaces the engineers and technicians to complete the entire process, obtains the desired effec The CAD/CAM system as well as plans the hardware, the software for supports the environment, (subsystem) realizes through each function module to the product description, the computation, the analysis, optimized, the cartography, the technological process design, the simulation as well as the NC processing.But the generalized CAD/CAM integrative system also should include aspects and so on production plan, management, quality control.Since 1946 first electronic accounting machine has been born in US, people on unceasing computer technology Introduces the machine design? Manufacture domain.As early as in the 50's, for the first time develops successfully the numerical control engine bed, may realize through the different numerical control procedure to the different components processing Afterwards, Massachusetts Institute of Technology's servo laboratory succeeds with the computer manufacture numerical control paper tape, has realized the NC programming automation.In this foundation, the people proposed the following tentative plan: The APT software is feeds the path method realization computer assistance programming through the description, that, can not describe feeds the path, but is direct description components itself? From this has had the CAD initial concept.The entire 50's, the electronic accounting machine also is in the electron tube time, uses the machine language programming, the computer mainly uses in thescience computation, also only has the output function for it disposition graph equipment.CADCAM system basic compositionCAD/CAM system hardware dispositionCAD/CAM system software compositionCAD/CAM system software dispositionComputer aided manufacturing (CAM) may define for uses the computer system to design, to manage and controls a productive plan the movement, through direct or indirect planned production resources computer contact surface.If defines states, the computer aided manufacturing application has 2 big aspects:1) computer supervisory control.This is the direct application, the computer with the production process connection, uses in supervising directly and the control production process2) produces the support application.This is the indirect application, middle the productive plan, the computer uses in supporting the production operation, but is not the computer and the production process links directly.Charting productive forces increaseThe CAD/CAM system may undertake the one whole set new charting theory to be able to strengthen the productivity.Again completes next step, keeps firmly in mind the entire design to be possible to store up the system.When the planner receives one with has saved the blueprint specification similar work piece, he only must recollect, and adjusts it the work storage place, revises in the original blueprint not to conform to a new work piece request part, productivity enhances.The original work piece efficiency enhances, but this can enhance the next step working efficiency.This is a complete at times renewal database support, can facilitate the user to use Improve mapping analysisThe charting analysis is another important work, it can by certain synthesize the CAD/CAM system automatic operation.This in pipeline design, in particular an important application.The pipeline design paper very is usually complex moreover must conform to the precise industry specification.The other giftedCAD/CAM also can affect a company in other aspects the project system.It can enhance the entire physical process the efficiency, the permission present project plan and the report procedure appraisal.CAD/CAM can improve improves the quality of the product the guarantee technology.It can automatic accurate and the integrity document material, the maintenance partial data accurate and bill of materials accurate.DeficiencyCAD/CAM insufficient spot not that obvious, but they can destroy even the most perfect design, the biggest shortcoming is only can directly skips from the manual charting and the recordpreservation to CAD/CAM, the elephant installs a set of jet engine in the populace automobile.The automobile possibly can run quick somewhat, but if the foundation enhancement has not coordinated the heavy pressure, the entire automobile can disperse the frame.CAD/CAM applicationSKETCHPAD, the CAD/CAM technology has passed through very long chi.It is already applied in the middle of each widespread industry.It uses in each aspect, controls from the airplane to the weapon research, manufactures from the map to the movement medical service, from circuit analysis to building steel analysis.CAD/CAM is being applied in each kind of charting and the production, installs the schematic diagram from the movie to the large-scale long-distance monitoring direct set battleship, its application to is developing variously.Now CAD/CAM market.Now in the market has four kind of different CAD/CAM sellers.First is some subordinate companies sells comes from a big enterprise part or the branch CAD/CAM technology.The IBM CAD/CAM branch is an example.If belongs to Mc-Donnell-Douglas McAuto; Belongs to General Electric Lalma, with belongs to Schlumberger Applican, if the multi-large number CAD/CAM subordinate company the main corporation has the massive service intercourse, not only sale supervisory system moreover when one's position is lowly one's words carry no weight service office.When they control the massive accounts also with provides the service, these companies on in optimum condition, because they may extract the massive profits.But they must undertake the complex administrative chain of command, this obstructs in them makes the fast response to the market tendency, or their itself studies and outside the development department, the merge improves on again their new production line the new technical developmentCAD/CAM technology and the product development road of futureAfter many year promotions, the CAD technology already widely applied in professions and so on machinery, electron, astronautics, chemical industry, building.Played using the CAD technology enhanced the enterprise the rated capacity, the optimization design proposal, reduces technical personnel's labor intensity, reduction design cycle, beefed-up design roles and so on standardization.In recent years, our country CAD technology development and the application have obtained the considerable development, besides has carried on sinicizing and the re-development to many overseas softwares, but also was born many had the independent copyright CAD system, If high Chinese CAD, opens item CAD and so on, because these software price is cheap, conforms to our country national condition and the standard, therefore has received widespread welcome, has won the more and more big market share. But, our country CAD/CAM software no matter is from the product development level from the commercialization, the marketability degree all has not the small disparity with the developed country.Because the overseas CAD/CAM software appears early, the development and the application time is also long,therefore they develop quite maturely, now basically already has seized the international market.These overseas software company uses its technical and the fund superiority, starts vigorously to our country market march At present, the overseas some outstanding softwares, like UG, SolidWorks, Pro/Engineer, CATIA and so on, already have seized part of domestic markets.Therefore, our country CAD/CAM software prospect is unoptimistic.But, we also should see clearly own superiority, for instance understood our country market, provides the technical support to be convenient, price small advantage and so on.Not only under these premises, we importantly with the trend of the times, the track international newest tendency, observe each international standard, in international domestic forms the oneself unique superiority, must base the home, the union national condition, face the domestic economic development need，develops has oneself characteristic, conforms to CAD/CAM software which the Chinese is familiar with.。

机械加工专业毕业设计外文翻译

附录ToolPurposeUpon completion of this unit, students will be able to:* Rough and explain the difference between finishing.* Choose the appropriate tool for roughing or finishing of special materials and processing.* Recognition Tool Cutting part of the standard elements and perspective.* The right to protect the cutter blade.* List of three most widely used tool material.* Description of each of the most widely used knives made of the material and its processing of Applications.* Space and inclination to understand the definition.* Grinding different tools, plus the principle of space and inclination.* To identify different forms of space and the inclination to choose the application of each form.The main points of knowledge:Rough-finished alloy steel casting materialScattered surplus carbide ceramic materials (junction of the oxide) ToolWith a chip breaking the surface roughness of the D-cutter knives diamondsAfter Kok flank behind the standard point of (former) angle off-chipSide front-side appearance and the outline of the former Kok (I. Kok)Grinding carbon tool steel front-fast finishing horn of rigid steelDouble or multiple-side flank before the dip angle oblique angleSurface-radius Slice root for curlingRough and finishing toolCutting speed only in the surface roughness not required when it is not important. Rough the most important thing is to remove the excess material scattered. Only in surface roughness of the finishing time is important. Unlike rough, finishing the slow processing speed. Chip off with the D-knives, better than the standard point of knives, in Figure 9-10 A, is designed for cutting depth and design, for example, a 5 / 16-inch box cutter blade of the maximum depth of cut 5 / 16 inches, and an 8 mm square block will be cutting knives Corner to 8 mm deep, this tool will be very fast Corner block removal of surplus metal. Slice merits of the deal with that, in a small blade was close thinning. This tool is also a very good finishing tool. But please do not confuse the thin band Tool and Tool-off crumbs. A chip-off is actually counter-productive tool to cut off the chip flakes.And the standard tool of the Corner, compared with chip breaking tool for the Corner is in its on and get grooving, Figure 9-10 B. This tool generally used to block the Corner of rough finishing. While this tool Corner blocks have sufficient strength to carry out deep cut, but the longer the chip will cut off the plane around after shedding a lot of accumulation. Chip is so because the tangles and sharp, and theoperator is a dangerous, so this is a chip from the need to address the problem. Double, or triple the speed of the feed will help to resolve, but this will require greater horsepower and still easily chip very long. Because of the slow processing, however, this action will be a good tool but also because of the small root radius of the processing will be a smooth surface. Especially when processing grey cast iron especially.Cutting Tools appearanceAppearance, sometimes called the contour of the floor plan is where you see the vision or the top down or look at the surface. Figure 9-11 illustrate some of the most common form, those who could be on the cutting tools and grinding out successfully be used. National Standards in its thread-cutting tool on a tiny plane can be as GB thread, the Anglo-American unity and international standards screw threads. A special tool to outline the thread of the plane is to be ground into the correct size.Tools Corner fixedCorner to a number of knives around the 15 degree angle while the other knives and cutting of the straight. When the mill in Figure 9-12 A and 9-12 B, for example by the space and the inclination, these must factor into consideration in the review. Figure 9-12 B Tool Corner block the angle is zero, compared with 9-12 A map is a heavier cutting tools, and the 9-12 A map will take more heat. The same amount of space in front of the two cases are the same.Tool Corner block component and the angleFigure 9-13 Tool Corner block an integral part of the name, and plans 9-14 point of the name, is the machinery industry standards.Grinding Wheel Tool Corner BlockWhen the cutter is fixed in the middle of Dao, Tool Corner block can not be the grinding. Can not do so for the reasons: because of the large number of Dao and extra weight, making Corner together with the grinding is a clumsy and inefficient way. Too much pressure could be added to round on the sand. This can cause the wheel Benglie wheel or because of overheating and the rift on the Corner Tool damage. There are grinding to the possibility of Dao.GrindingA craftsman in his toolbox, should always be a small pocket lining grinding tool. Alumina lining a grinding tool as carbon tool steel and high speed steel tool tool. The silicon carbide lining grinding tool grinding carbide cutting tools. Cutting Tools should always maintain smooth and sharp edge, so that the life expectancy of long knives and processing the surface smooth.Cutting tool materialsCarbon tool steel cutter Corner block usually contains 1.3 percent to 0.9 percent of carbon. These make use of the cutting tool in their tempering temperature higher than about 400 degrees Fahrenheit (205 degrees Celsius) to 500 degrees Fahrenheit (260 degrees Celsius) remained hardness, depending on the content of carbon. These temperature higher than that of carbon tool steel cutter will be changed soft, and it will be the cutting edge. Damaged. Grinding blades or cutting speed faster when using carbon tool steel cutter will be made of the blue, this will be in the imagination. Toolwill be re-hardening and tempering again. So in a modern processing almost no carbon as a tool steel blade.Low-alloy steel cutting tool in the carbon steel tools added tungsten, cobalt, vanadium alloying elements such as the consequences. These elements and the hardness of high-carbon carbide. Increased tool wear resistance. Alloy tool steel that is to say there will be no hard and fast with hot red when the knife's edge can still continue to use it. Low-alloy steel cutting tool is relatively small for a modern processing.High-speed steel with tungsten of 14 percent to 22 percent, or Containing 1.5% to 6% of the W-Mo (molybdenum which accounted for 6 percent to 91 percent). From high-speed steel tool made of a rigid heat, some high-speed steel also contains cobalt, which is formed of rigid factor. Cobalt containing high-speed steel tool can maintain hardness, more than 1,000 degrees Fahrenheit (or 540 degrees Celsius) blade will become soft and easily damaged. After cooling, the tool will harden. When grinding, you must be careful because of overheating and cold at first, so that profile Benglie Zhucheng a variety of metal alloy materials have a special name called Carbide, such as containing tungsten carbide cobalt chrome. In little or iron carbide. However, its high-speed steel cutting speed than the maximum cutting speed is higher 25 percent to 80 percent. Carbide Tool General for cutting force and the intermittent cutting processing, such as processing Chilled Iron.The past, Carbide Tool is mainly used for processing iron, but now carburizing tool for processing all the metal.Carbide Tool into the body than to the high-speed steel tool or casting - lighter alloy cutting tools, because tend to be used as a tool carbide cutting tools. Pure tungsten, carbon carburizing agent or as a dipping formation of the tungsten carbide, suitable for the cast iron, aluminum, non-iron alloy, plastic material and fiber of the machining. Add tantalum, titanium, molybdenum led to the carbon steel The hardness of higher tool, this tool suitable for processing all types of steel. In manufacturing, or tungsten steel alloy containing two or more of a bonding agent and the mixture is hard carbon steel tool, is now generally containing cobalt, cobalt was inquiry into powder and thoroughly mixed, under pressure Formation of Carbide.These cutting tools in the temperature is higher than 1,660 degrees F (870 degrees C) can also be efficiently used. Carbide Tool hardware than high-speed steel tool, used as a tool for better wear resistance. Carbide Tool in a high-speed Gangdao nearly three times the maximum cutting speed of the cutting rate cutting.Made from diamonds to the cutting tool on the surface finish and dimensional accuracy of the high demand and carbide cutting tools can be competitive, but these tools processing the material was more difficult, and difficult to control. Metal, hard rubber and plastic substances can be effective tool together with diamonds and annoyance to the final processing.Ceramic tool (or mixed oxide) is mixed oxide. With 0-30 grade alumina mixture to do, for example, contains about 89 percent to 90 percent of alumina and 10 percent to 11 percent of titanium dioxide. Other ceramic tool is used with the tiny amount of the second oxides Mixed together the cause of pure alumina.Ceramic tools in more than 2,000 degrees F (1095 degrees C) temperature of the work is to maintain strength and hardness. Cutting rates than high-carbon steel knives to 50 percent or even hundreds of percentage. In addition to diamonds and titanium carbide, ceramic tool in the industry is now all the materials of the most hard cutting tool, especially at high temperatures.Tao structure easily broken in a specific situation, broken only carbon intensity of the half to two-thirds. Therefore, in cut, according to the proportion of cutting and milling would normally not be recommended. Ceramics cutting machine breakdown of failure is not usually wear failure, as compared with other materials, their lack of ductility and lower tensile strength.In short, the most widely used by the cutting tool material is cut high-speed steel, low alloy materials and carbide.Gap and dipSpace and inclination of the principle is the most easily to the truck bed lathe tool bladed knives to illustrate. Shape, size of the gap, and dip the type and size will change because of machining. Similarly a grinding tool Corner block is just like brushing your teeth.Gap tool to stop the edge of friction with the workpiece. If there is no gap in Figure 9-15A in the small blades, knives and the side will wear will not be cutting. If there are gaps in Figure 9-15 B, will be a cutting tool. This basic fact apply to any type of tool.Clearance was cutting the size depends on material and the cutting of the material deformation. For example, aluminum is soft and easy to slightly deformed or uplift, when the cutter Corner into space within the perspective and the perspective of the space under, the equivalent in steel mill and will very quickly broken. Table 9-1 (No. 340) that different materials grinding space and perspective.The correct amount of space will be properly protected edge. Too much space will cause the blade vibration (fibrillation), and may edge of total collapse. Tool Corner for the slab block must have a backlash, behind (in front) gap, knife and cut-corner. The main cutting edge is almost as all the cutting work at the cutting edge of the cutting tool on the edge, on the left or right-lateral knives, or cutting tool in the end, cut off on a cutter.Backlash angle for example, the role of a lathe tool Corner to the left block when it mobile. If there is no backlash Kok, Fig 9-16 A, with the only tool will be part of friction rather than cutting. If a suitable backlash Kok, Fig 9-16 B, will be cutting edge and will be well supported. If I have too many gaps, Fig 9-16 C, the edge will not support leading tool vibration (fibrillation) and may be completely broken.Tool gap to the front or rear of the role when it fixed to zero, as shown in Figure 9-17. If not in front of the Gap. Figure 9-17 A, the tool will not only friction and cutting. If a suitable space in front, Fig 9-17 B, but also a good tool will be cutting edge will be well supported. If a big gap in front of Ms, Fig 9-17 C, the tool will lack support, will have a vibrate, and cutting edge may be pressure ulcer.Figure 9-18 illustrate the gap in front of a lathe tool, when it with a 15 degree angle when fixed. The same amount of space on the front fixed to zero, and around thecutter, but the tool is the relatively thin. So the heat away from the blade less. Typically, front-side or front-not too big in Figure 9-19. It is usually from zero degrees to 20 degrees change, an average of about 15 degrees. There are clear advantages, according to the following: good cutting angle so that the cutting edge of the work was well, but relatively thin chips. Cutting Tools is the weakest part. By the former angle, the blade In the form of points around the workpiece. Cutting Edge shock will cause the entire tool vibration. When cutting the work nearly completed, the final section of metal was to ring, packing iron sheet or tangles in the form of the metal ball away gradually replaced by direct removal. Pressure tends to stay away from the workpiece cutting tool rather than narrow the gap between its parts. 9-19 A in the plan was an example of the use of a 30-degree lateral Cutting Angle tool processing thin slice example. A mathematical proof of the plan 9-19 B in the right-angle triangle trip is to expand the use of a map 9-19 A right triangle in the same way, that is, in the direction of upward mobility to feed a 0.010 inch. Right triangle adjacent to the edge (b) and feed 0.010 feet equivalent.The following formula using triangulation to explain:Kok cosine A = right-angle-B / C XiebianOr cosine of 30 degrees = b / c0.886 = b/0.010b = 0.866 * 0.010b = 0.00866 (bladed too thin)When the mobile tool, the purpose of front-to be processed to eliminate from the surface of the cut-cutting tools. This angle is usually from 8 degrees to 15 degrees, but in exceptional circumstances it as much as 20 degrees to 30 degrees. If there is no gap in Figure 9-20 A, cutting tools will be tied up, sharp beep, and the rivets may be the first to die away. The appropriate space, in Figure 9-20 B, cutting tool will be cutting well.A manufacturing plant or cut off the fast-cutter blade with three space, in a root-surface or surface and the other in bilateral level, in Figure 9-21. If a tool Corner block from the date of the face, It can have up to five space, in Figure 9-22. Grooving tool sometimes known as area reduction tool used to cut a groove in the shallow end of the thread.Inclination is the top tool inclination or, in the Tool Corner block on the surface. Changes depending on the angle of the cutting material. Improvement of the cutting angle, the blade shape, and guidelines from the chip from the edge of the direction. Chip dip under the direction named. For example, if a chip from the edge cutter outflow, it is called anterior horn. If the chip to the back of the outflow, that is, to the Dao, which is known as the horn. Some mechanical error and the staff horn as a front-or knife corner.Single tool like Tool Corner block may be the only edge of the blade side oblique angle, or in the back, only to end on the edge of the horn, or they may have roots in the face or front surface of the main Cutting edge of the blade and cutting edge of the horn and a roll angle of the portfolio. In the latter case, cut off most of the surface with a cutter and a chip to the point of view in the tool horn and roll angle in bothdirections has been moved out.Two different roll angle in Figure 9-23 A and 9-23 B was an example. Angle depends on the size and type of material was processed.9-24 A map in Figure 9-24 B and gives examples of zero to a fixed cutter after the two different angle. In Figure 9-25 B and 9-25 A Tool to the regular 15-degree angle. Figure 9-26 tool to display a 15 degree angle fixed, but in this case a tool to roll angle after angle and the combination of form close to the workpiece. Double or multiple chips to lead the inclination angle of a mobile or two away from the edge of the back and side to stay away from the cutter.Comparison of various horn, shown in Figure 9-27, Corner of the horn of a negative point of view, and zero is the point of view. These dip in the Corner cutter on the manifestation of a decision in the hands of the processing needs of the pieces. After Kok was the size of the type of materials processing, and knives in Dao fixed on the way.The type of lateral oblique angleFigure 9-28 examples of tools Corner blocks and four different types of lateral oblique angle of the cross-sectional. Figure 9-28 A, is zero lateral oblique angle, like some of the brass materials, some bronze and some brittle plastic material is particularly necessary. Standard side oblique angle, in Figure 9-28 B, is the most common one of the bevel side. In the ductile material on the deep cut, easy to chip in the tool around the accumulation of many, and this will cause danger to the operator. The chip will become a deal with the problem. Such a tool to cut off the grey cast iron is the most appropriate.Chip laps volumes, Figure 9-28 C, is one of the best types of inclination, especially in the ductile material on the special deep cutting. Chip small crimp in close formation against the Dao of bladed knives against the will of the rupture. The chip rolled up to maintain a narrow trough of the chip will guarantee that the width of closely Lane V ol. The chip is very easy to handle. V olume circle with a chip is not a cut-chip.Chip cut off, in Figure 9-28 D, leading to chip in the corner was cut off, and then to small chips fell after the chip. The need to cut off a chip provides up to 25 percent of the force. This inclination of the stickiness of the steel is good.Gap KokWhen cutting any material time, the gap should always be the smallest size, but the gap should never angle than the required minimum angle small space. The gap is too small knives Kok will lead to friction with the workpiece. Choice of space at the corner to observe the following points:1. When processing hardness, stickiness of the material, the use of high-speed steel tool cutting angle should be in the space of 6 to 8 degrees, and the use of carbon tool steel cutter at the corner of the gap in size should be 5 degrees to 7 degrees.2. When the processing of carbon steel, low carbon steel, cast iron when the gap angle should be the size of high-speed steel tool 8 degrees to 12 degrees, and carbon tool steel cutter 5 degrees to 10 degrees.3. Scalability when processing materials such as copper, brass, bronze, aluminum,iron, etc. Zhanxing materials, space Kok should be the size of high-speed steel tool 12 degrees to 16 degrees, carbon steel knives 8 degrees to 14 , Mainly because of the plastic deformation of these metals. This means that, when the cutter and around them, the soft metal to some minor deformation or protruding, and this tool will be friction. At this time, we must have a tool on the additional space.刀具目的在完成这一个单元之后，学生将会能够:* 解释粗加工和精加工之间的差别。

机械类毕业设计外文翻译--龙门式起重机金属材料的疲劳强度预测

英文文章：Fatigue life prediction of the metalwork ofa travelling gantry craneV.A. KopnovAbstractIntrinsic fatigue curves are applied to a fatigue life prediction problem of the metalwork of a traveling gantry crane. A crane, used in the forest industry, was studied in working conditions at a log yard, an strain measurements were made. For the calculations of the number of loading cycles, the rain flow cycle counting technique is used. The operations of a sample of such cranes were observed for a year for the average number of operation cycles to be obtained. The fatigue failure analysis has shown that failures some elements are systematic in nature and cannot be explained by random causes.卯1999 Elsevier Science Ltd. All rights reserved.Key words: Cranes; Fatigue assessment; Strain gauging1. IntroductionFatigue failures of elements of the metalwork of traveling gantry cranes LT62B are observed frequently in operation. Failures as fatigue cracks initiate and propagate in welded joints of the crane bridge and supports in three-four years. Such cranes are used in the forest industry at log yards for transferring full-length and sawn logs to road trains, having a load-fitting capacity of 32 tons. More than 1000 cranes of this type work at the enterprises of the Russian forest industry. The problem was stated to find the weakest elements limiting the cranes' fives, predict their fatigue behavior, and give recommendations to the manufacturers for enhancing the fives of the cranes.2. Analysis of the crane operationFor the analysis, a traveling gantry crane LT62B installed at log yard in the Yekaterinburg region was chosen. The crane serves two saw mills, creates a log store, and transfers logs to or out of road trains. A road passes along the log store. The saw mills are installed so that the reception sites are under the crane span. A schematic view of the crane is shown in Fig. 1.1350-6307/99/$一see front matter 1999 Elsevier Science Ltd. All rights reserved.PII: S 1 3 5 0一6307(98) 00041一7A series of assumptions may be made after examining the work of cranes:·if the monthly removal of logs from the forest exceeds the processing rate, i.e. there is a creation of a logstore, the crane expects work, being above the centre of a formed pile with the grab lowered on the pile stack;·when processing exceeds the log removal from the forest, the crane expects work above an operational pile close to the saw mill with the grab lowered on the pile;·the store of logs varies; the height of the piles is considered to be a maximum;·the store variation takes place from the side opposite to the saw mill;·the total volume of a processed load is on the average k=1.4 times more than the total volume of removal because of additional transfers.2.1. Removal intensityIt is known that the removal intensity for one year is irregular and cannot be considered as a stationary process. The study of the character of non-stationary flow of road trains at 23 enterprises Sverdlesprom for five years has shown that the monthly removal intensity even for one enterprise essentially varies from year to year. This is explained by the complex of various systematic and random effects which exert an influence on removal: weather conditions, conditions of roads and lorry fleet, etc. All wood brought to the log store should, however, be processed within one year.Therefore, the less possibility of removing wood in the season between spring and autumn, the more intensively the wood removal should be performed in winter. While in winter the removal intensity exceeds the processing considerably, in summer, in most cases, the more full-length logs are processedthan are taken out.From the analysis of 118 realizations of removal values observed for one year, it is possible to evaluate the relative removal intensity g(t) as percentages of the annual load turnover. The removal data fisted in Table 1 is considered as expected values for any crane, which can be applied to the estimation of fatigue life, and, particularly, for an inspected crane with which strain measurement was carried out (see later). It would be possible for each crane to take advantage of its load turnover per one month, but to establish these data without special statistical investigation is difficult. Besides, to solve the problem of life prediction a knowledge of future loads is required, which we take as expected values on cranes with similar operation conditions.The distribution of removal value Q(t) per month performed by the relative intensity q(t) is written aswhere Q is the annual load turnover of a log store, A is the maximal designed store of logs in percent of Q. Substituting the value Q, which for the inspected crane equals 400,000 m3 per year, and A=10%, the volumes of loads transferred by the crane are obtained, which are listed in Table 2, with the total volume being 560,000 m3 for one year using K,.2.2. Number of loading blocksThe set of operations such as clamping, hoisting, transferring, lowering, and getting rid of a load can be considered as one operation cycle (loading block) of the crane. As a result to investigations, the operation time of a cycle can be modeled by the normal variable with mean equal to 11.5 min and standard deviation to 1.5 min. unfortunately, this characteristic cannot be simply used for the definition of the number of operation cycles for any work period as the local processing is extremely irregular. Using a total operationtime of the crane and evaluations of cycle durations, it is easy to make large errors and increase the number of cycles compared with the real one. Therefore, it is preferred to act as follows.The volume of a unit load can be modeled by a random variable with a distribution function(t) having mean22 m3 and standard deviation 6;一3 m3, with the nominal volume of one pack being 25 m3. Then, knowing the total volume of a processed load for a month or year, it is possible to determine distribution parameters of the number of operation cycles for these periods to take advantage of the methods of renewal theory [1].According to these methods, a random renewal process as shown in Fig. 2 is considered, where the random volume of loads forms a flow of renewals:In renewal theory, realizations of random:，，，having a distribution function F-(t), are understoodas moments of recovery of failed units or request receipts. The value of a processed load:，，after}th operation is adopted here as the renewal moment.＜t﹜. The function F-(t) is defined recurrently,Let F(t)=P﹛nLet v(t) be the number of operation cycles for a transferred volume t. In practice, the total volume of a transferred load is essentially greater than a unit load, and it is useful therefore totake advantage of asymptotic properties of the renewal process. As follows from an appropriatelimit renewal theorem, the random number of cycles v required to transfer the large volume t hasthe normal distribution asymptotically with mean and variance.without dependence on the form of the distribution function月t) of a unit load (the restriction is imposed only on nonlattice of the distribution).Equation (4) using Table 2 for each averaged operation month,function of number of load cycles with parameters m,. and 6,., which normal distribution in Table 3. Figure 3 shows the average numbers of cycles with 95 % confidence intervals. The values of these parametersfor a year are accordingly 12,719 and 420 cycles.3. Strain measurementsIn order to reveal the most loaded elements of the metalwork and to determine a range of stresses, static strain measurements were carried out beforehand. Vertical loading was applied by hoisting measured loads, and skew loading was formed with a tractor winch equipped with a dynamometer. The allocation schemes of the bonded strain gauges are shown in Figs 4 and 5. As was expected, the largest tension stresses in the bridge take place in the bottom chord of the truss (gauge 11-45 MPa). The top chord of the truss is subjected to the largest compression stresses.The local bending stresses caused by the pressure of wheels of the crane trolleys are added to the stresses of the bridge and the load weights. These stresses result in the bottom chord of the I一beambeing less compressed than the top one (gauge 17-75 and 10-20 MPa). The other elements of the bridge are less loaded with stresses not exceeding the absolute value 45 MPa. The elements connecting the support with the bridge of the crane are loaded also irregularly. The largest compression stresses take place in the carrying angles of the interior panel; the maximum stresses reach h0 MPa (gauges 8 and 9). The largest tension stresses in the diaphragms and angles of the exterior panel reach 45 MPa (causes 1 and hl.The elements of the crane bridge are subjected, in genera maximum stresses and respond weakly to skew loads. The suhand, are subjected mainly to skew loads.1, to vertical loads pports of the crane gmmg rise to on the otherThe loading of the metalwork of such a crane, transferring full-length logs, differs from that of a crane used for general purposes. At first, it involves the load compliance of log packs because of progressive detachment from the base. Therefore, the loading increases rather slowly and smoothly.The second characteristic property is the low probability of hoisting with picking up. This is conditioned by the presence of the grab, which means that the fall of the rope from the spreader block is not permitted; the load should always be balanced. The possibility of slack being sufficient to accelerate an electric drive to nominal revolutions is therefore minimal. Thus, the forest traveling gantry cranes are subjected to smaller dynamic stresses than in analogous cranes for general purposes with the same hoisting speed. Usually, when acceleration is smooth, the detachment of a load from the base occurs in 3.5-4.5 s after switching on an electric drive. Significant oscillations of the metalwork are not observed in this case, and stresses smoothly reach maximum values.When a high acceleration with the greatest possible clearance in the joint between spreader andgrab takes place, the tension of the ropes happens 1 s after switching the electric drive on, the clearance in the joint taking up. The revolutions of the electric motors reach the nominal value in O.}r0.7 s. The detachment of a load from the base, from the moment of switching electric motors on to the moment of full pull in the ropes takes 3-3.5 s, the tensions in ropes increasing smoothly to maximum. The stresses inthe metalwork of the bridge and supports grow up to maximum values in 1-2 s and oscillate about an average within 3.5%.When a rigid load is lifted, the accelerated velocity of loading in the rope hanger and metalwork is practically the same as in case of fast hoisting of a log pack. The metalwork oscillations are characterized by two harmonic processes with periods 0.6 and 2 s, which have been obtained from spectral analysis. The worst case of loading ensues from summation of loading amplitudes so that the maximum excess of dynamic loading above static can be 13-14%.Braking a load, when it is lowered, induces significant oscillation of stress in the metalwork, which can be }r7% of static loading. Moving over rail joints of 3} mm height misalignment induces only insignificant stresses. In operation, there are possible cases when loads originating from various types of loading combine. The greatest load is the case when the maximum loads from braking of a load when lowering coincide with braking of the trolley with poorly adjusted brakes.4. Fatigue loading analysisStrain measurement at test points, disposed as shown in Figs 4 and 5, was carried out during the work of the crane and a representative number of stress oscillograms was obtained. Since a common operation cycle duration of the crane has a sufficient scatter with average value } 11.5min, to reduce these oscillograms uniformly a filtration was implemented to these signals, and all repeated values, i.e. while the construction was not subjected to dynamic loading and only static loading occurred, were rejected. Three characteristic stress oscillograms (gauge 11) are shown inFig. 6 where the interior sequence of loading for an operation cycle is visible. At first, stressesincrease to maximum values when a load is hoisted. After that a load is transferred to the necessary location and stresses oscillate due to the irregular crane movement on rails and over rail joints resulting mostly in skew loads. The lowering of the load causes the decrease of loading and forms half of a basic loading cycle.4.1. Analysis of loading process amplitudesTwo terms now should be separated: loading cycle and loading block. The first denotes one distinct oscillation of stresses (closed loop), and the second is for the set of loading cycles during an operation cycle. The rain flow cycle counting method given in Ref. [2] was taken advantage of to carry out the fatigue hysteretic loop analysis for the three weakest elements: (1) angle of the bottom chord(gauge 11), (2) I-beam of the top chord (gauge 17), (3) angle of the support (gauge 8). Statistical evaluation of sample cycle amplitudes by means of the Waybill distribution for these elements has given estimated parameters fisted in Table 4. It should be noted that the histograms of cycle amplitude with nonzero averages were reduced afterwards to equivalent histograms with zero averages.4.2. Numbers of loading cyclesDuring the rain flow cycle counting procedure, the calculation of number of loading cycles for the loading block was also carried out. While processing the oscillograms of one type, a sample number of loading cycles for one block is obtained consisting of integers with minimum and maximum observed values: 24 and 46. The random number of loading cycles vibe can be describedby the Poisson distribution with parameter =34.Average numbers of loading blocks via months were obtained earlier, so it is possible to find the appropriate characteristics not only for loading blocks per month, but also for the total number of loading cycles per month or year if the central limit theorem is taken advantage of. Firstly, it is known from probability theory that the addition of k independent Poisson variables gives also a random variable with the Poisson distribution with parameter k},. On the other hand, the Poisson distribution can be well approximated by the normal distribution with average}, and variation },. Secondly, the central limit theorem, roughly speaking, states that the distribution of a large number of terms, independent of the initial distribution asymptotically tends to normal. If the initial distribution of each independent term has a normal distribution, then the average and standard deviation of the total number of loading cycles for one year are equal to 423,096 and 650 accordingly. The values of k are taken as constant averages from Table 3.5. Stress concentration factors and element enduranceThe elements of the crane are jointed by semi-automatic gas welding without preliminary edge preparation and consequent machining. For the inspected elements 1 and 3 having circumferential and edge welds of angles with gusset plates, the effective stress concentration factor for fatigue is given by calculation methods [3], kf=2.}r2.9, coinciding with estimates given in the current Russian norm for fatigue of welded elements [4], kf=2.9.The elements of the crane metalwork are made of alloyed steel 09G2S having an endurance limit of 120 MPa and a yield strength of 350 MPa. Then the average values of the endurance limits of the inspected elements 1 and 3 are ES一l=41 MPa. The variation coefficient is taken as 0.1, and the corresponding standard deviation is 6S-、一4.1 MPa.The inspected element 2 is an I-beam pierced by holes for attaching rails to the top flange. The rather large local stresses caused by local bending also promote fatigue damage accumulation. According to tablesfrom [4], the effective stress concentration factor is accepted as kf=1.8, which gives an average value of the endurance limit as ES 一l=h7 Map. Using the same variation coiffing dent th e stand arid d emit ion is 1s σ-=6.7 MPa.An average S-N curve, recommended in [4], has the form:with the inflexion point No=5·106 and the slope m=4.5 for elements 1 and 3 and m=5.5 for element 2.The possible values of the element endurance limits presented above overlap the ranges of load amplitude with nonzero probability, which means that these elements are subjected to fatigue damage accumulation. Then it is possible to conclude that fatigue calculations for the elements are necessary as well as fatigue fife prediction.6. Life predictionThe study has that some elements of the metalwork are subject to fatigue damage accumulation.To predict fives we shall take advantage of intrinsic fatigue curves, which are detailed in [5]and [6].Following the theory of intrinsic fatigue curves, we get lognormal life distribution densities for the inspected elements. The fife averages and standard deviations are fisted in Table 5. The lognormal fife distribution densities are shown in Fig. 7. It is seen from this table that the least fife is for element 3. Recollecting that an average number of load blocks for a year is equal to 12,719, it is clear that the average service fife of the crane before fatigue cracks appear in the welded elements is sufficient: the fife is 8.5 years for element 1, 11.5 years for element 2, and h years for element 3. However, the probability of failure of these elements within three-four years is not small and is in the range 0.09-0.22. These probabilities cannot be neglected, and services of design and maintenance should make efforts to extend the fife of the metalwork without permitting crack initiation and propagation.7. ConclusionsThe analysis of the crane loading has shown that some elements of the metalwork are subjectedto large dynamic loads, which causes fatigue damage accumulation followed by fatigue failures.The procedure of fatigue hfe prediction proposed in this paper involves tour parts:(1) Analysis of the operation in practice and determination of the loading blocks for some period.(2) Rainflow cycle counting techniques for the calculation of loading cycles for a period of standard operation.(3) Selection of appropriate fatigue data for material.(4) Fatigue fife calculations using the intrinsic fatigue curves approach.The results of this investigation have been confirmed by the cases observed in practice, and the manufacturers have taken a decision about strengthening the fixed elements to extend their fatigue lives.中文翻译龙门式起重机金属材料的疲劳强度预测v.a.科普诺夫摘要内在的疲劳曲线应用到龙门式起重机金属材料的疲劳寿命预测问题。

机械毕业设计英文外文翻译255计算机与制造业

附录2英语原文The Computer and ManufacturingComputer Aided DesignThe computer is bringing manufacturing into the Information Age. This new tool, a long familiar one in business and management operations, is moving into the factory, and its advent is changing manufacturing as certainly as the steam engine changed it 100 years ago.The basic metal working processes are not likely to change fundamentally, but their organization and control definitely will.IN one respect, manufacturing could be said to be coming full circle. The first manufacturing could was a cottage industry: the designer was also the manufacturer, conceiving and fabricating products one at a time. Eventually, the concept of the interchangeability of parts was developed, production was separated into specialized functions, and identical parts were produced thousands at a time.Today, although the designer and manufacturer may not become one again, the functions are being drawn close in the movement toward an integrated manufacturing system,It is perhaps ironic that, at a time when the market demand a high degreed of product diversification, the necessity for increasing productivity and reducing costs is driving manufacturing toward integration into a coherent system, a continuous process in which parts do not spend as much as 95% of production time being moved around or waiting to be worked on.The computer is the key to each of these twin requirements. It is the only tool that can provide the quick reflexes, the flexibility and speed, to meet a diversified market. And it is the only tool that enables the detailed analysis and the accessibility of accurate data necessary for the integration of the manufacturing system.It may well be that, in the future, the computer may be essential to a company’s survival. Many of today’s businesses will fade away to be replaced by more-productive combinations. Such more-productive combinations aresuper-quality, super-productivity plants. The goal is to design and operate a plant that would produce 100% satisfactory parts with good productivity.A sophisticated, competitive world is requiring that manufacturing begin to settle for more, to become itself sophisticated, To meet competition, for example, a company will have to meet the somewhat conflicting demands for greater product diversification, higher quality, improved productivity, and low prices.The company that seeks to meet these demands will need a sophisticated tool, one that will allow it to respond quickly to customer needs while getting the most out of its manufacturing resources.The computer is that tool.Becoming a “super-quality, super-productivity” plant requires the integration of an extremely complex system. This can be accomplished only when all elements of manufacturing—design, fabrication and assembly, quality assurance, management, materials handling—are computer integrated.In product design, for example, interactive computer-aided-design (CAD) systems allow the drawing and analysis tasks to be performed in a fraction of the time previously required and with greater accuracy. And programs for prototype testing and evaluation further speed the design process.In manufacturing planning, computer-aided process planning permits the selection, from thousands of possible sequences schedules, of the optimum process.On the shop floor, distributed intelligence in the form of microprocessors controls machines, runs automated loading and unloading equipment, and collects data on current shop conditions.But such isolated revolutions are not enough. What is needed is a totally automated system, linked by common software from front door to back.The benefits range throughout the system. Essentially, computer integration provides widely and instantaneously available, accurate information, improving communication between departments, permitting tighter control, and generally enhancing the overall quality and efficiency of the entire system.Improved communication can mean, for example, designs that are more producible. The NC programmer and the tool designer have a chance to influence the product designer, and vice versa.Engineering changes, thus, can be reduced, and those that are required can be handled more efficiently. Not only does the computer permit them to be specifiedmore quickly, but it also alerts subsequent users of the data to the fact that a change has been made.The instantaneous updating of production-control data permits better planning and more0effective scheduling. Expensive equipment, therefore, is used more productively, and parts move more efficiently through production, reducing work-in-process costs.Product quality, too, can be improved. Not only are more-accurate designs produced, for example, but the use of design data by the quality-assurance department helps eliminate errors due to misunderstandings.People are enabled to do their jobs better. By eliminating tedious calculations and paperwork—not to mention time wasted searching for information—the computer not only allows workers to be more productive but also frees them to do what only human beings can do: think creatively.Computer integration may also lure new people into manufacturing. People are attracted because they want to work in a modern, technologically sophisticated environment.In manufacturing engineering, CAD/CAM decreases tool-design. NC-programming, and planning times while speeding the response rate, which will eventually permit in-house staff to perform work that is currently being contracted out.According to the Tool & Manufacturing Engineers Handbook, process planning is the systematic determination of the methods by which a product is to be manufactured economically and competitively. It essentially involves selection, calculation, and documentation. Processes, machines, tools, and sequences must be selected. Such factors as feeds, speeds, tolerances, dimensions, and costs must be calculated. Finally, documents in the form of setup instructions, work instructions, illustrated process sheets, and routings must be prepared. Process planning is an intermediate stage between designing and manufacturing the product. But how well does it bridge design and manufacturing?Most manufacturing engineers would agree that, if ten different planners were asked to develop a process plan for the same part, they would probably come up with ten different plans. Obviously, all these plans cannot reflect the most efficient manufacturing methods, and, in fact, there is no guarantee that any one of them will constitute the optimum methods for manufacturing the part.What may be even more disturbing is that a process plan developed for a part during a current manufacturing program may be quite different manufacturing program and it may never be used again for the same or similar part during a previous similar part. That represents a lot of wasted effort and produces a great many inconsistencies in routing, tooling, labor requirements, costing, and possibly even purchase requirements.Of course, process plans should not necessarily remain static. As lot sizes change and new technology, equipment, and processes become available, the most effective way to manufacture a particular part also changes, and those changes should be reflected in current process plans released to the shop.A planner must manage and retrieve a great deal of data and many documents, including established standards, machine ability data, machine specifications, tooling inventories, stock availability, and existing process plans. This is primarily an information-handling job, and the computer is an ideal companion.There is another advantage to using computers to help with process planning. Because the task involves many interrelated activities, determining the optimum plan requires many iterations. Since computers can readily perform vast numbers of comparisons, many more alternative plans can be explored than would be possible manually.A third advantage in the use of computer-aided process planning is uniformity.Several specific benefits can be expected from the adoption of computer-aided process-planning techniques:● Reduced clerical effort in preparation of instructions.● Fewer calculation errors due to human error.● Fewer oversights in logic or instructions because of the prompting capability available with interactive computer programs.● Immediate access to up-to-date information from a central database.● Consistent information, because every planner accesses the same database.● Faster response to changes requested by engineering of other operating departments.● Automatic use of the latest revision of a part drawing.● More-detailed, more-uniform process-plan statements produced by word processing techniques.● More-effective use of inventories of tools, gages, and fixtures and aconcomitant reduction in the variety of those items.● Better communication with shop personnel because plans can be more specifically tailored to a particular task and presented in unambiguous, proven language.● Better information for production planning, including cutter-life, forecasting, materials-requirements planning, scheduling, and inventory control.Most important for CIM, computer-aided process planning produces machine-readable data instead of hand written plans. Such data can readily be transferred to other systems within the CIM hierarchy for use in planning.There are basically two approaches to computer-aided process planning: variant and generative.In the variant approach, a set of standard process plans is established for all the parts families that have been identified through group technology. The standard plans are stored in computer memory and retrieved for new parts according to their family identification. Again, GT helps to place the new part in an appropriate family. The standard plan is then edited to suit the specific requirements of a particular job.In the generative approach, an attempt is made to synthesize each individual plan using appropriate algorithms that define the various technological decisions that must be made in the course of manufacturing. In a truly generative process-planning system, the sequence of operations, as well as all the manufacturing-process parameters, would be automatically established without reference to prior plans. In its ultimate realization, such an approach would be universally applicable: present any plan to the system, and the computer produces the optimum process plan.No such system exists, however. So called generative process-planning system—and probably for the foreseeable future—are still specialized systems developed for a specific operation or a particular type of manufacturing process. The logic is based on a combination of past practice and basic technology.Computer Aided ManufacturingNumerical ControlNumerical control can be defined as a form of programmable automation in which the process is controlled by numbers,letters,and symbols.In NC, thenumbersform a program of instructions designed for a particular workpart or job. When the job changes, the program of instructions is changed .This capability to change the program for each new job is what gives NC its flexibility, It is much easier to write new programs than to make major change in the production equipment.NC equipment is used in all areas of metal parts fabrication and comprises roughly 15% of the modern machine tools in industry today. Since numerically controlled machines are considerably more expensive than their conventional counterparts, the asset value of industrial NC machine tools is proportionally much larger than their numbers. Equipment utilizing numerical control has been designed to perform such diverse operations as drilling, milllng~; ~r~j, gtindlng, :sheetmetal pres~orkingi spot welding, arc welding, riveting, assembly, drafting, inspection, and parts handling. And this is by no means a complete list. Numerical control should be considered as a possible mode of controlling the operation for any production situation possessing the following characteristics:I, .Similar workparts in terms of raw material(e. g., metal stock for machining)2. The workparts are produced in various sizes and geometries.3. The workparts are produced in batches of small to medium-sized quantities.4. A sequence of similar processing steps is required to complete the operation oneach workpiece.Many machining jobs meet these conditions. The machined workparts are metal,they are specified in many differentsizes and shapes, and most machined parts produced in industry today are made in small to medium-size lot sizes.To produce each part,a sequence of drilling operations may be required, or a series of turning or milling operations. The suitability of NC for these kinds of jobs is the reason for the tremendous growth of numerical control in the metalworking industry over the last 25 years.Basic Components of an NC systemAn operational numerical control system consists of the following three basic components:1.Program of instructions.2.Controller unit, also called machine control unit (MCU)3.Machine tool or other controlled processThe program of instructions serves as the input to the controller unit , which inturn commands the machine tool or other process to be controlled.Program of instructionsThe program of instructions is the detailed step-by-step set of directions which tell the machine tool what to do. It is coded in numerical or symbolic form on some type of input medium that can be interpreted by the controller unit. The most common input medium is 1-inch-wide punched cards, magnetic tape,and even 35-mm motion picture film.There are two other methods of input to the NC system which should be mentioned. The first is by manual entry of instructional data to the controller unit .This is time-consuming and is rarely used except as an auxiliary means of control or when only one or a very limited number of parts are to be made. The second method of input is by means of a direct link with a computer .This is called direct numerical control, or DNC.The program of instructions is prepared by someone called a part programmer. Theprogramm er’s job is to provide a set of detailed instructions by which the sequence of processing steps is to be performed. For a machining operation, the processing steps involve the relative movement of the machine tool table and the cutting tool.Controller unitThe second basic component of the NC system is the controller unit . This consists of the electronics and hardware that read and interpret the program of instructions and convert it into mechanical actions of the machine tool . The typical elements of the controller unit include the tape reader , a data buffer, signal output channels to the machine tool, feedback channels from the machine tool, and the sequence controls to coordinate the overall operation of the foregoing elements.The type reader is an electrical-mechanical device for winding and reading the punched tape containing the program of instructions . The data contained on the tape are read into the data buffer , The purpose of this device is to store the input instructions in logical blocks of information. A block of information usually represents one complete step in the sequence of processing elements. For example, one block may be the data required to move the machine table to a certain position and drill a hole at that location .The signal output channels are connected to the servomotors and other controls in the machine tool. Through these channels, the instructions are sent to themachine tool from the controller unit. To make certain that the instruction have been properly executed by the machine, feedback data are sent back to the controller via the feedback channels. The most important function of this return loop is to assure that table and workpart have been properly located with respect to the tool. Most NC machine tools in use today are provided with position feedback controls for this purpose and are referred to ae closed-loop systems. However, in recent years there has been a growth in the use of open-loop systems, which do not make use of feedback signals to the controller unit. The advocates of the open-loop concept claim that the reliability of the system is great enough that feedback controls are not needed and are an unnecessary extra cost.Sequence controls coordinate the activities of the other elements of the controller unit. The tape reader is actuated to read data into the buffer from the tape, signals are sent to，and so on. These types of operations must be synchronized and this is the function of the sequence controls.Another element of the NC system, which may be physically part of the controller unit or part of the machine tool, is the control panel. The control panel or control consolecontains the dials and switches by which the machine operator runs the NC system. It may also contain data displays to provide information to the operator. Although the NC system is an automatic system, the human operator is still needed to turn the machine on and off, to change tools (some NC systems have automatic tool changers), to load and unload the machine, and to perform various other duties. To be able to discharge these duties, the operator must be able to control the system, and this is done through the control panel.The third basic component of an NC system is the machine tool or other controlled process. It is the part of the NC system which performs useful work. In the most common example of an NC system, one designed to perform machining operations, the machine tool consists of the worktable and spindle as well as the motors and controls necessary to drive them. It also includes the cutting tools, work fixtures, and other auxiliary equipment needed in the machining operation. Programmable Logic ControllersA programmable logic controller (PLC) is a solid-state device used to control machine motion or process operation by means of a stored program. The PLC sends output control signals and receives input signals through input/output (I/O) devices.A PLC controls outputs in response to stimuli at the inputs according to the logic prescribed by the stored program The inputs are made up of limit switches, ,pushbuttons, thumbwheels, switches, pulses, analog signals, ASCII serial data, and binary or BCD data from absolute position encoders. The outputs are voltage or current levels to drive end devices such as solenoids, motor starters, relays, lights, and so on. Other output devices include analog devices, digital BCD displays, ASCII compatible devices servo variable-speed drives, and even computers.Programmable controllers were developed (circa in 1968) when General Motors Corp, and other automobile manufacturers were experimenting to see if there might be an alternative to scrapping all their hardwired control panels of machine tools and other production equipment during a model changeover. This annual tradition was necessary because rewiring of the panels was more expensive than buying new ones. The automotive companies approached a number of control equipment manufacturers and asked them to develop a control system that would have a longer productive life without major rewiring, but would still be understandable to and repairable by plant personnel. The new product was named a "programmable controller".The processor part of the PLC contains a central processing unit and memory. The central processing unit (CPU) is the "traffic director" of the processor, the memory stores information. Coming into the processor are the electrical signals from the input devices, as conditioned by the input module to voltage levels acceptable to processor logic. The processor scans the state of I / O and updates outputs based on instructions stored in the memory of the PLC. For example, the processor may be programmed so that if an input connected to a limit switch is true (limit switch closed), then a corresponding output wired to an output module is to be energized. This output might be a solenoid, for example. The processor remembers this command through its memory and compares on each scan to see if that limit switch is, in fact, closed. If it is closed, the processor energizes the solenoid by turning on the output module.The output device, such as a solenoid or motor starter, is wired to an output module's terminal, and it receives its shift signal from the processor, in effect, the processor is performing a long and complicated series of logic decisions. The PLC performs such decisions sequentially and in accordance with the stored program. Similarly, analog I / O allows the processor to make decisions based on themagnitude of a signal, rather than just if it is on or off. For example, the processor may be programmed to increase or decrease the steam flow to a boiler (analog output) based on a comparison of the actual temperature in the boiler {analog input) to the desired temperature. This is often performed by utilizing the built-in PID (proportional, integral, derivative) capabilities of the processor.Because a PLC is "software based", its control logic functions can be changed by reprogramming its memory. Keyboard programming devices facilitate entry of the revised program, which can be designed to cause an existing machine or process to operate in a different sequence or to respond to different levels of, or combinations of stimuli. Hardware modifications are needed only if additional, changed, or relocated input/output devices are involved.Transfer MachinesThe highest degree of automation obtainable with special-purpose, multifunction machines is achieved by using transfer machines. Transfer machines are essentially acombination of individual workstations arranged in the required sequence, connected by work transfer devices, and integrated with interlocked controls. Workpieces are automatically transferred between the. stations, which are equipped with horizontal vertical, or angular units to perform machining, gaging, workpiece repositioning, assembling, washing, or other operations. The two major classes of transfer machines are rotary and in-line types.An important advantage of transfer machines is that they permit the maximum number of operations to be performed simultaneously There is relatively no limitation on the number of workpiece surfaces or planes that can be machined, since devices can be interposed in transfer machines at practically any point for inverting, rotating, or orienting the workpiece, so as to complete the machining operations. Work repositioning also minimizes the need for angular machining heads and allows operations to be performed in optimum time. Complete processing, from rough, casting or forgings to finished parts is often possible.One or more finished parts are produced on a transfer machine with each index of thetransfer system that moves the parts from station to station. Production efficiencies of such machines generally range from 50% for a machine producing a variety of different parts to 85% for a machine producing one part, in. highproduction, depending upon the workpiece and how the machine is operated (materials handling method, maintenance procedures, etc. )All types of machining operations, such as drilling, tapping, reaming, boring, and milling, are economically combined on transfer machines. Lathe-type operations such as turning and facing are also being performed on in-line transfer machine, with the workpieces being rotated in selected machining stations. Turning operations are performed in lathe-type segments in which multiple toolholders are fed on slides mounted on tunnel-type bridge units. Workpieces are located on centers and rotated by chucks at each turning station. Turning stations with CNC are available for use on in-line transfer machines. The CNC units allow the machine cycles to be easily altered to accommodate changes in workpiece design and can also be used for automatic tool adjustments.Maximum production economy on transfer lines is often achieved by assembling partsto the workpieces during their movement through the machine. Such items as bushings, seals, welch plugs, and heat tubes can be assembled and then machined or tested during the transfer machining sequence. Automatic nut torquing following the application of part subassemblies can also be carried out.Gundrillinq or reaming on transfer machines is an ideal applicat!on provided that proper machining units are employed and good bushing practices are followed. Contour boring and turning of spherical seats and other surfaces can be done with tracer-controlled single-point inserts, thus eliminating the need for costly special form tools. In-process gaging of reamed or bored holes and automatic tool setting are done on transfer machines to maintain close tolerances.Less conventional operations sometimes performed on transfer machines include grinding, induction heating of ring gears for shrink-fit pressing on flywheels, induction hardening of valve seats, deep rolling to apply compressive preloads, and burnishinq.Transfer machines have long been used in the automotive industry for producing identical components at high production rates with a minimum of manual part handling. In addition to decreasing labor requirements, such machines ensure consistently uniform, high-quality parts at lower cost. They are no longer confined just to rough machining and now often eliminate the need for subsequent operations such as grinding and honing.More recently, there has been an increasing demand for transfer machines to handle lower volumes of similar or even different parts in smaller sizes, with means for quick changeover between production runs. Built-in flexibility, the ability to rearrange andinterchange machining units, and the provision of idle stations increases the cost of any transfer machine, but such features are economically feasible when product redesigns are common. Many such machines are now being used in nonautomotive applications for lower production requirements.Special features now available to reduce the time required for part changeover include standardized dimensions, modular construction, interchangeable fixtures mounted on master pallets that remain on the machine, interchangeable fixture components, the ability to lock out certain stations for different parts by means of selector switches, and programmable controllers. Product design is also important, and common transfer and clamping surfaces should be provided on different parts whenever possible.中文翻译计算机与制造业计算机辅助设计计算机正在将制造业带入信息时代。

机械类毕业设计外文及其翻译

译文原文题目：State of the art in robotic assembly 译文题目：用机械手装配的发展水平学院：机电工程学院专业班级：09级机械工程及自动化01班学生姓名：学号：From:/kns/brief/default_result.aspxState of the art in robotic assemblyRobotic assembly systems offer good perspectives for the rationalization of assembly activities. Various bottlenecks are still encountered, however, in the widespread application of robotic assembly systems. This article focuses on the external developments, bottlenecks and development tendencies in robotic assembly.External developmentsThe current market trends are:Increasing international competition, shorter product life cycle, increasing product diversity, decreasing product quantity, shorter delivery times, higher delivery reliability, higher quality requirements and increasing labour costs. Next to these market developments, technological developments also play a role, offering new opportunities to optimize price, quality and delivery time in their mutual relationships. The technological developments are among other things: information technology, new design strategies, new processing techniques, and the availability of flexible production systems, such as industrial robots. Companies will have to adjust their policy to these market and technology developments (market pull and technology push, respectively). This policy is determined by the company objectives and the company strategy which lie at its basis. Under the influence of the external developments mentioned, the company objectives can, in general, be divided into: high flexibility, high productivity, constant and high product quality, short throughput times, and low production costs. Optimizing these competition factors normally results in the generation of more money, and thus (greater) profits. To realize this objective, most companies choose the following strategies: reduction of complexity, application of advanced production technologies, integral approach, quality control, and improvement of the working conditions. Figure 1 shows the company policy in relation to the external developments to which the company policy should be adjusted.Figure 1. External developments and company policyWith regard to the product and production development, a subdivision can be made intothe following strategies which involve[1]:The product: design for manufacturing/assembly, a short development time, a more frequent development of new products, function integration to minimize the number of parts, miniaturization and standardization.The process: improved controllability, shorter cycle times and minimal stocks. There is a trend increasingly to carry out processes in discrete production in flow form.The production system: the use of universal, modular, and reliable system components, high system flexibility (in relation to decreasing batch sizes, and increasing product variants), and the integration of product systemsin the entire production.State of the artParts manufacturing and assembly together form coherent sub-processes within the production process. In parts manufacturing, the raw material is processed or transformed into product parts in the course of which the form, sizes and/or properties of the material are changed. In assembly the product parts are put together into subassemblies or into final products. Figure 2 shows the relationships between these functional processes and the most important control processes within an industrial enterprise. This shows that assembly by means of material or product flows is linked to parts manufacturing, and that by means of information flows it is integrated with marketing, product planning, product development, process planning and production control.Figure 2. Assembly as part of the production processAssembly forms an important link in the whole manufacturing process, because this operational activity is responsible for an important part of the total production costs and the throughput time. It is one of the most labour-intensive sectors in which the share of the costs of the assembly can amount from 25 to 75 per cent of the total production costs[1]. Research shows that the share of the labour costs in the assembly in relation to the total manufacturing costs is approximately 45 per cent for lorry engines, approximately 55 per cent for machine tools, and approximately 65 per cent for electrical apparatus[1]. The centre of the cost items。

机械毕业设计英文外文翻译97带式运输机

附录二：外文技术资料及中文翻译1、英文技术资料Belt ConveyorFIELD OF THE INVENTIONThe present invention relates to a belt conveyor having a circulating conveying belt, having carrying rollers, which are arranged between the top strand and the bottom strand of the conveying belt, and having a drive device and a force-transmission device for moving the conveying belt.BACKGROUND OF THE INVENTIONIt is known from practice for force to be transmitted from the drive device to the conveying belt of a belt conveyor via friction fitting. The friction between a driven carrying roller and the conveying belt, for example, may even be sufficient for this purpose. The rest of the carrying rollers are mounted in a movable manner and rotate along.DE 42 44 170 C2 discloses a belt conveyor having an endless conveying belt, the latter being driven by means of a force-transmission device which is present in the form of a friction wheel. A drive shaft extends beneath the bottom strand of the conveying belt. On the inner radius of the belt curve, a motor is connected as a drive device to the drive shaft and, in the region of the outer radius, a friction wheel is seated on the drive shaft and is in contact with the outer surface of the conveying belt. In this case, the friction wheel interacts with a carrying roller functioning as counterpressure roller. The drive shaft is mounted such that it can be moved at an angle both in the region of the outer radius and in the region of the inner radius of the belt curve. The movable-angle mounting of the drive shaft allows adaptation of the extent to which the friction wheel is pressed against the conveying belt in proportion to the actual load. In this way, the wear is reduced if, in part-load operation, the conveying belt is only subjected to the contact-pressure force which is necessary for this purpose.Although the belt conveyor known from DE 42 44 170 C2 reduces the wear of the conveying belt, it cannot rule it out altogether. The task of conveying foodstuffs or other goods which are to be kept clean involves, in addition to the mechanical damage to the conveying belt, the aspect of hygiene and of keeping goods clean. The abraded surface particles of the conveying belt could have a considerable adverse effect on the quality of the goods which are to be conveyed. Moreover, the known belt conveyor requires an extremely high level of structural outlay as far as the movable mounting of the separate drive shaft is concerned. SUMMARY OF THE INVENTIONTaking as departure point the belt conveyor known from DE 42 44 170 C2, the object of the invention is to specify a belt conveyor of the type in question which largely rules out any adverse effect to the surface of the conveying belt of the belt conveyor by the force-transmission device. According to a particularly preferred configuration, the belt conveyor is intended to require just a low level of structural outlay.The above object is achieved by the features of Patent claim 1. According to the latter, a belt conveyor of the type in question is configured such that a pair of elements which interact with one another with a form fit is provided for force-transmission purposes, and that one element is assigned to the force-transmission device and the other element is assigned to the conveying belt.According to the invention, it has been found that the surface of the conveying belt is not adversely affected as a result of the action of the force-transmission device if a separate pair of elements is providedin order to realize force transmission. It has also been found that the use of a pair of movement-converting elements which are known per se and interact with one another with a form fit largely eliminates the disadvantages which are known in the case of friction-fitting movement conversion, in particular wear and abrasion.According to a preferred exemplary embodiment of the belt conveyor according to the invention, the pair of elements could be present as toothed ring and toothed belt, the tooth flanks of the toothed ring and of the toothed belt interacting with one another. It would be possible for the toothed ring to be assigned to the force-transmission device and for the toothed belt to be assigned to the conveying belt.As far as a particularly low level of structural outlay is concerned, a preferred configuration of the abovementioned exemplary embodiment provides that the toothed ring is assigned to a carrying roller, and the latter thus simultaneously assumes the role of the force-transmission device. Via a journal projecting from the carrying roller, the drive takes place by means of a motor. The toothed ring could be plugged onto the carrying roller and fixed releasably—for example via a shaft/hub connection or a feather key—to the same. In the case of a plugged-on toothed ring, it is advantageous that it is possible to use carrying rollers which are already present. It is particularly advantageous for each carrying roller to be assigned at least one toothed ring. Over the entire running path of the conveying belt, it would then be the case that the toothed belt and the toothed rings interengage and move the conveying belt in a dimensionally stable manner. Corresponding to the toothed ring or rings which is/are arranged between the top and bottom strands and belongs/belong to the preferred configuration mentioned above, the toothed belt is arranged on the underside of the conveying belt, and extends in the running direction of the same. Arranging the toothed belt on the underside of the conveying belt once again ensures that the top side of the conveying belt, which is charged if appropriate with goods which are to be kept clean, is not subject to any force transmission, mechanical damage or production of abrasion particles or other contaminants.An expedient development of the preferred configuration of the belt conveyor according to the invention makes provision for the toothed ring to be arranged at the end of the carrying roller. As a result, on the one hand, straightforward maintenance of the force-transmission device is made possible and, on the other hand, this arrangement is also more cost-effective than a, for example, central arrangement. Direct force transmission over a short distance is achieved by a journal for the connection of the drive device projecting from that end of the carrying roller which is provided with the toothed ring.It is particularly advantageous if the toothed belt extends in the region of the side border of the conveying belt. As a result, on the one hand, straightforward production of the conveying belt with the toothed belt is made possible by the direct relationship to the border region and, on the other hand, a role is also played here by the accessibility to the pair of elements for maintenance purposes and, of course, by the coordination between the toothed belt and the arrangement of the toothed ring.In addition to toothed belts and toothed rings with normal toothing, it would also be possible to realize multisplining. This further reduces undesired sliding and thus wear, heating and noise development. In order to absorb high tensile forces, it would be possible for Kevlar filaments to be incorporated in the toothed belt, which usually consists of plastic. It would be possible for the conveying belt to be produced with the toothed belt by welding, vulcanizing or adhesive bonding.According to a particularly preferred configuration, it would be possible for the toothed belt to be a constituent part of a toothed- belt component which is of essentially U-shaped design in the transverse direction of the toothed belt. The U-shape makes it possible for the toothed- belt component simply to be plugged onto the border of the conveying belt until the border region has come into contact with the base part between the U-legs. The inner surface of the toothed- belt component may have been provided with adhesive beforehand. As a result of its shaping and of being produced in this way, the toothed- beltcomponent engages around the side-border region of the conveying belt.While the toothed belt of the conveying belt is subjected to compressive force by the toothed ring, and this largely rules out detachment of the toothed- belt component on the underside of the conveying belt, a counterpressure device could be provided in order to secure that region of the toothed- belt component which extends on the top side of the conveying belt. In design terms, the counterpressure device could be present in the form of an arm which acts on the U-leg of the toothed- belt component on the top side and thus constantly presses the same onto the top side of the conveying belt.As far as reliable guidance is concerned, it would be possible for the toothed belt or the toothed- belt component containing the toothed belt to form a bead. A bead ridge is thus produced over the length of the conveying belt. In the case of a U-shaped toothed- belt component, the bead ridge extends in each case at the free ends of the U-legs, at a distance from the border of the conveying belt, the distance depending essentially on the width of the toothed belt. As an alternative to a bead ridge, it would be possible for the toothed- belt component or for the straightforward toothed belt also to have at least one beveled free end. The guidance measure taken on the toothed belt or on the specific toothed- belt component is provided in order that a guide roller or a pair of guide rollers acts on the beveled surface or on the bead or bead ridge. The guidance measure explained above could be taken equally well in the case of belt curves and straight belt lines and of belt S-shapes bridging different heights.In the case of belt curves, the force acting on the conveying belt is directed toward the inner radius of the belt curve, with the result that the guide rollers, in an advantageous manner which is known per se, could have inclined running surfaces. Correspondingly angled retaining arms as a constituent part of retaining structures for the guide rollers could be arranged in each case in the region of a carrying roller. The guide rollers could be arranged in pairs on the top strand and on the bottom strand of the conveying belt.It should be emphasized at this point that, with the abovementioned configuration of the belt conveyor according to the invention having the bead or beveled free ends, two functions are combined in the pair of form-fitting elements. Not only the force transmission, but also the guidance of the conveying belt, takes place. The dimensional stability of the conveying belt is advantageously increased by the pair of form-fitting elements with the specific configuration of the toothed belt or of the toothed- belt component for action of the guide rollers thereon.In the case of the already cited design of the belt conveyor in the form of a belt curve, the carrying rollers are of conical design and the toothed ring is arranged at the larger-diameter end of the respective carrying roller, that is to say on the outer radius of the belt curve. The drive device is present as a motor and is assigned to the first carrying roller of the belt curve. The form-fitting interengagement of the toothed wheel and toothed belt takes place in the region of each carrying roller, the form fit, in relation to the first, motor-driven carrying roller, serving for force-transmission purposes and, in relation to the rest of the rollers, serving for guiding the conveying belt.The previously explained principle of force transmission via a pair of elements which interact with one another with a form fit could also be used in the case of a straight belt line or in the case of a height-changing belt S-shape. Here, the carrying rollers are of a cylindrical design and the force transmission takes place—as with the belt curve—at a first carrying roller, while the following carrying rollers, likewise equipped with the pair of form-fitting elements, serve for guiding the conveying belt. In contrast to the belt curve, however, it would be possible, in the case of the straight belt line or in the case of the belt S-shape, for the pair of elements to be arranged at the two free ends of the respective carrying roller and on the two border regions of the conveying belt. It would thus be possible specifically for the two border regions of the conveying belt to have a toothed belt or a toothed- belt component which interacts with the toothed rings at the two free ends of each carrying roller. Furthermore, it would also be possible, with these types of construction of the belt conveyor according to the invention, to provideguide rollers.A further advantage of the preferred embodiment of the belt conveyor according to the invention, the toothed ring and toothed belt interacting, consists in the improved capacity for controlling the belt speed in accordance with the current loading. It would be possible to provide a control device which senses a change in the speed by corresponding measuring sensors and adjusts the power of the drive device in line with the safety regulations.In comparison with the force transmission realized by friction fitting, the belt conveyor according to the invention not only has the advantage of better capacity for control, but also has the advantage that the conveying belt has a high level of dimensional stability as a result of the guidance by means of the pair of form-fitting elements and by means of the pairs of guide rollers and can be subjected to higher torques. Overall, it is possible to achieve an increased level of drive power during start-up. In the case of the belt conveyor according to the invention being designed in the form of a belt curve with an inner radius of 400 mm, the carrying rollers rotate at 230 rpm at a maximum speed of 1.5 m/sec.2、中文翻译带式运输机一、领域的发明本发明涉及一种具有循环带式输送机输送带，有托辊，这是链之间的顶部和底部的传送带链排列，有一个传动装置和一个移动传送带力传动装置。

机械专业毕业设计外语翻译

本科毕业设计（论文）外文译文院（系）：机电工程学院专业：机械设计制造及其自动化姓名：学号：外语文献翻译原文：3.4.1CAD HARDWAREComputersThere are two major types of hardware used in a CAD system. Computer and input/output (I/O) devices. In the early days of CAD. Some commercial CAD systems used proprietary computers. Today, nearly all CAD software runs on a general-purpose computer.Depending on the complexity of the CAD package, it may require a mainframe computer, a minicomputer, or simply a microcomputer. In general, the more functionalities a CAD system provides, the more powerful the computer needed. Three dimensional solid modelers require much more computing than do two-dimensional drafting systems; thus, they need more powerful computers. Systems that integrate engineering analysis or simulation packages generally are more computation-intensive. A powerful computer not only speeds up the response of a CAD system, but also can support multiple users without significant performance degradation.Several other parameters and components concerning the computer also have to be considered.CAD HARDWARErandom-access memory (RAM)capacitypermanent disk-storage capacityspecial graphics acceleratortape backupsRAM is the actual physical memory (vs. virtual memory)of a computer. A small memory capacity means slow processing due to frequent swapping between the physical memory and the virtual memory on disk. Because CAD is extremely storage demanding, disk capacity is important. Small disk capacity limits the system to the storage of only a few drawings. CAD is graphics-based and requires tremendous data processing. A graphics accelerator can drastically increase the performance of the system. Another component, the hard disk, is typically the major cost of a computer system. Therefore, it is not cost-justifiable to store all drawings on line on disk. Magnetic tape is still the most economical medium to use for off-line data storage. It is necessary for a CAD system to have a tape backup subsystem.Currently, all levels of computers are used in CAD systems. Personal computers are used in low-cost,2-D drafting applications, and with the new power of these computers, hey are also being used for some 3-D solid modeling applications. Engineering workstations have been the mainstay in CAD, and are usually a single-user CAD workstation in a network. Minicomputers are used in multiuser CAD systems. Mainframes are used for large multiuser CAD systems to support real time simulation and engineering analysis. Sometimes, in a large corporation, all levelsof CAD systems are implemented. All these systems are linked together through a hierarchical computer network.3.4.2 Input. Output (I/O)DevicesFigure 3.7 shows the typical I/O devices used in a CAD system. Input devices are generally used to transfer information from a human or storage medium to a computer where ”CAD functions” are carried out. A keyboard is the standard input device used to transmit alphanumeric data to the system. Function keypads are also used to make input easier. Joysticks, track balls, and mousse are also used to manipulate a cursor. They can be used to position the graphic cursor(e.g. cross hair)on a monitor and feed back the location of an object on the monitor to the computer. Using these devices allows an operator to address terminal locations to interactively in reaching an accurate position. Mouses have been used extensively with windows and pull-down menus. They are easy to use for pointing; However, using a mouse to trace a curve is not an easy task.There are three basic approaches to input an existing drawing;(1)model the object on a drawing,(2)digitize the drawing, or (3)scan the object. Digitizing is usually much easier than modeling. A digitizer is a device that translates the X-Y locations on a drawing than modeling. A digitizer is a device that translates the X-Y locations on a drawing into a digital and feeds that signal to a computer. Graphics scanners scan a drawing and convert it to a CAD-system-readable format. Some scanners have built-in character-recognition software that can convert characters on paper into ASCII codes. Another input device is a sketch pad called a graphics tablet. A graphics tablet is a special flat surface on which a user draws with a stylus. The location of the stylus is sent to the computer. The tablet is an absolute coordinate device. It is easy to implement overlay menus on the tablet and pull down menus on the screen to improve the operation. Currently. the tablet is the most popular input device used in CAD other than the keyboard.The standard output device for CAD is a monitor display. Modern monitor displays are raster-scan display monitors. Similar to a TV monitor, an electron gun(Sony Trinitron uses three guns for three basic colors)sends an electronic beam to the front of the monitor. Easy display dot is called a pixel(picture element).For color displays, each pixel is represented by three closely located dots with red, green , and blue colors. The electronic beam selects the color elements and the intensity of each color element. The resolution of the monitor is determined by the number of different colors or gray scales displayable at each pixel, usually measured in bits, A 1-bit display can turn each pixel either ON or OFF.A gray scale has at least v2 bits. A 1-bit display can turn each pixel either ON or OFF.A gray scale has at least 2 bits which allow three light intensities plus an OFF (2*2).Usually, displays are 4 bits(16 colors),8 bits(256 colors),16 bits(thousands of colors),and 24bits (millions of colors).The electronic beam sweeps the screen from the top to the bottom line by line. Because the dot is lit for only a very short period of time, the sweep must be done very quickly in order not to have a flickering image. The refresh rate is a measure of how many times the monitor is redrawn in one second.The computer does not draw directly on the monitor. Connecting the computer to the monitor is u-sually a RGB(red, green, blue)cable. Three separate signal lines are connected. On the graphics board in the computer are circuits to generate the analog signals required to drive the monitor. There is also a frame buffer that serves as memory to store the image. Each pixel on the screen has a corresponding address in the frame buffer. The data in the frame buffer are converted into the appropriate analog signal and sent to the monitor at the refresh rate. Separately, the computer writes directly to the frame buffer the image it intends to draw. The greater the display size and number of colors, the more frame buffer is needed. The frame buffer on the graphics board is made of random-access memory(RAM).The calculator lend support toes to paint the software AutoCAD to make us can be with the sketch that the astonishing speed draw the engineering sketch or machine sketch and other with accuracy to sophisticate. The calculator paints to paint the different place, one of them with handicraft the paintings with out the diagram divide a step proceed of, because of but would sometimes appear the traditional handicraft the painting hour the problem of the impossible emergence. General circumstance bottom, usage the AutoCAD proceeds painting, control the precision painting and not that difficult, but want accurate then need the certain technique out the diagram. Us- ually paint or outsing diagram to have no to need to change to measure to AutoCAD system worth make the modification with establish, take its the province worth can normal work, but have the special request, must modify the related system to change measure; Too sometimes the request of the diagram paper with make the diagram's way of doing the antinomy, and be to adopt the to make the diagram method to can't attain the request of the diagram paper, will adopt some techniqueiques to modify the related system to change to measure, and can make the calculator draw to attain the request of the diagram paper with output's sketch.AutoCAD line type establishing of comparison At teaching of process inside would usually run into what this kind of circumstance, while establishing diagram layer, clearly established the point lin eationed, and consequently output to however investigate its reason for the solid lined, and is usually because of the line typed the establishing of comparison is not appropriate and cau-sable. Should you so establish the comparison of what kind of line type? How to use the line type the comparison in the painting?Usage AutoCAD painting, besides continuous line type( Continuous), the other line type is all from the solid line segment, blank segment, point series for or text this constituting. On-line type definition document the inside have already defined these line types the segment's standard length, and show on held the act or at print the machine\ painting output, each length and ex-portation comparison with line type comparison direct proportion. When show or print, the painting boundary that customer that request, this hour establish is out of accordance with the painting boundary of the province difference big, on held the act show or paint output's line type would match the engineering graphics to will pass the changes line type comparison the system the method that change the deal, enlarge orcontract all line types each a small segment of length, make the sketch made meet the request. In the Auto CAD, imply the adjustment line type the comparison's order: Overall situation line type comparison factor tie department exportation ratio for line type ratio factor, used foring the control not continuous line type. The Ltscale is right to have the object validity, Celtscale the province for to new object validating, twoly changing the deal w-orth all for 1.For use the line type that Auto CAD2002 painting, big part contain three kinds of forms,( such as: Comparison that Center, Center2, Center*2, Dashed, Dashed2, Dashed*2) the first is a half, the third line type for the standard form, the second line type that comparison that the first line type is the first line type of two times, if line type the comparison establish to is not suitable for, and would then make some exportation diagrams the line( such as the point lineation, dotted line...etc.) change into a solid line.Two, line breadth the count of establishPass by what handicraft painting, its painting with outs the diagram is a synchronous proceeding of, now calculator painting, its painting with outs the diagram divide a step proceeds. Wether draw the construction engineering diagram or machine spare parts diagram, at print control that a work that exportation engineering drawing, the most is a line to print the drawing the breadth, line the type, color, seal a line breadth for, and eachly growing to line type all contain its cowgirl, in the AutoCAD painting process of the old edition, even defined the line type the width, its at see the diagram area can't also display the line type the width's differentiation.( not contain many righteousness lines the Pline)Width for color for can passing the diagram layer or set upping the line coming distinguish analysing the line.What research of current painting tries a, adopt of is this kind of method.But in the AutoCAD2002, add entity that" Lweight"( line type the width establish) order, provided the new function for customer, then make use of the entity characteristic to proceed the control, and establish the line breadth for the sketch, and make use of it can at hold the act to up show with print to output, control the entity's line breadth.2002 versions inside print to establish and can is divided into three part, and for printing machine belong to the sex to establish, print the style to establish respectively and the page establish.Because of the model of breadth line the space is different from diagram manifestation of space paper result, in the model space therefore the elephant vegetable show, but in the diagram paper the space is then then to print the width to proceed to show, because of but we while drawing ske tch should know at the diagram line that true width established by line breadth of model space, and is not equal with object. When the line breadth is worth to establish to"0", it show with the minimum width( plain breadth of an elephant) on held the act, and the line breadth settle to other worth, then come showing with the worth specific value of plain width and true unit of elephant.Three, the sketch output the establishing of comparison When we draw sketch that comparison that comparison output the sketch with us hour use different, canmake originally text in the sketch that draw word exportation comparison for marking noting waiting in the output's sketch take placing changing, therefore at drawing the sketch before returning the beard make suring the sketch.For guaranteeing the sketch to output our want the literalness size, should when the text word establish usage following formula: The text word draws the high degree the = the text word output high degree* the sketch to output the comparison; The sketch outputs the comparison= output the diagram the length for of length( width)/ diagram.( width) draw the width of the diagram line to also should consider this point, its to settle the width same as output the width to multiply by with its comparison worth.From above practice with analyze to can see out, calculator painting and incompletelyresemble handicraft painting so synchronously paint with out diagram, therefore sometimes make with the diagram method can't attain the request of the diagram paper. Some in common use system that this demand we are deep into control the calculator to paint the theories, and can expertly control the operation method to change the deal with establish the technique, and can make the work of our painting more convenient, smooth, consumedly increase to paint the level with paint the efficiency.译文：3.4.1CAD硬件计算机两大主要类型的硬件使用于CAD系统，计算机和输入/输出设备。

机械毕业设计英文外文翻译605自卸车概述

附录附录A 英文文献Dump Truck OverviewCompartment is equipped with automatic devices for dumping cars. Also known as dump trucks, construction vehicles, from motor vehicle chassis, hydraulic lifting mechanism, taking the composition of power devices andFreight platform.In civil engineering, often with the excavators, loaders, belt conveyors, such as joint operations, constitute a loading, transportation and unloading production lines, to carry out earthworks, gravel, loading and unloading loose materials transport. Compartment can be loaded automatically as a result of a certain tipping point of discharge, discharge significant savings of time and labor, reduce the transport cycle, increase productivity, reduce transportation costs, and to identify the loading capacity. Transport machinery is commonly used.Engine, chassis and cab of the truck the same structure and general. Can train to the tipping or lateral tipping, through manipulation of the system control rod movement, tipping beyond the more common to promote the piston rod so that tipping inside. A small number of two-way tipping. The allocation of oil by high-pressure valves, tubing into the lifting hydraulic cylinder, inside the front fenders have a driver's safety. Engine through the transmission, hydraulic pump driven from power devices, hydraulic tipping body inside fuel tanks, hydraulic pumps, distribution valves, hydraulic lifting cylinder, control valves and tubing and other components. Hydraulic tipping body inside the tank, pump, distribution valves, hydraulic lifting cylinder, control valves and tubing and other components. Engine through the transmission, hydraulic pump driven from power plant, high pressure oil through the distribution valve, hydraulic cylinder tubing into the lift, push rod so that tipping inside. After tipping more to the common piston rod through the control system to control movement, will enable the train to stop at any position on the need for the tilt. Compartments use of its own gravity and hydraulic control reset.Dump Truck of the main technical parameters are loaded with weight, and marked volume loading. New car or car repair factory commissioning must be carried out so thatthe process inside a smooth lifting action without strings. Use of the site shall be the right choice of lubricating oil, saving unloading time and labor, the attention of lubrication cycle, lifting oil change schedule strictly. Shipment according to nominal load, overloading is strictly prohibited.Dump truck classification:1. In accordance with the carrying capacity of the chassis can be divided into series dump truck, dump in tons of series and series of large-tonnage Dump;2. By the driver dump the form of the bridge can be divided into single-, double-bridge dump, dump eight after the first four, the first four series of ten different models;3. By unloading the hydraulic lifting mechanism can be divided into different Monacrosporium biparietal dump and dump.Structural analysis of the dump truck:Mainly by the hydraulic dump truck dump bodies, cars, and its annexes constitute the frame. Hydraulic dump them inside the structure of institutions and manufacturers in various different modifications, the following compartments and the lifting mechanism in accordance with the pattern of the two aspects of the structure of that dump truck.1、compartment typeNode compartments by use of different body types can be broadly divided into: general rectangular bucket compartment and inside mine.Ordinary rectangular compartments for the carriage of goods in bulk. Plate with subsequent automatic opening and closing of institutions, to ensure smooth unloading of goods. Ordinary rectangular compartment thickness as follows: pre-board 4 to 6mm, side panels 4 to 8 mm, after the board 5 to 8 mm, bottom 6 to 12 mm. For example: dump truck license ChengLi common standard rectangular compartment thickness as follows: 4 at the end of the first 4 side 8 5.Inside bucket mining is applicable to a larger particle size, such as large stones of goods in transit. Taking into account the impact of goods and touch buildings, mining bucket inside the design of more complex shape, with thicker material. For example:-way power bucket mining dump truck license compartment standard thickness as follows: 6 at the end of the first 6 edges 10, and some models in the floor on some angle iron welded to increase the train capacity of stiffness and impact resistance.2 、lifting body typeDump truck lifting mechanism is the core of the primary advantages and disadvantages of discriminant indicators truck.Type lifting mechanism common current: F-type lifting mechanism to enlarge tripod, T-style tripod lifting mechanism to enlarge, double lift, the former top-lift and double rollover.Enlarge tripod-type lifting mechanism is currently the most frequently used means of a lift for 8 to 40 tons of dead weight, train length of 4.4 ~ 6 meters. Advantage of the structure of mature, stable lifting and cheap; disadvantages inside the frame on the main floor of the closed height of the larger plane.Most forms of double lift truck in 6X4, it is in the second on both sides of the bridge in front of more than one level of the tank is installed (usually 3 ~ 4), the hydraulic cylinder on the fulcrum of a direct role in the compartment floor. Double advantage of lifting the main floor for the inside frame of the closing high on a smaller plane; the shortcomings of the hydraulic system is very difficult to ensure synchronization of two hydraulic cylinders, give less smooth Health on the inside bottom of the overall stiffness higher.Lift the top way before the simple structure, inside the frame on the main floor of the closed high plane can be very small, vehicle stability, the smaller the hydraulic system pressure, but the first trip at the most larger-cylinder class, the high cost .Double-sided cylinder roll force is better, less travel to achieve double-rollover; but more complex hydraulic piping, Health cited a higher rate of roll-over accident.Dump Truck Selection:Dump Truck with the development and improvement of domestic purchasing power, dump truck is not in the traditional sense, what the living can do everything dump truck, from the design point of view is different goods, different working conditions, the development of different regions of different products. This requires users to buy vehicles specific to the use of manufacturers.1、chassisIn the selection of the chassis, the economic benefits that are to be considered, such as: the price of the chassis, loading quality, overloading the capacity of 100 kilometers fuel consumption, maintenance fee, etc.. In addition, users should also consider the following chassis parameters:① plane height on the chassis frame. General 6x4 chassis frame height on the planefor the 1050 ~ 1200. The higher the value the greater the vehicle center of gravity, the more easily overturned. Factors affecting the value is the tire diameter, suspension of the layout and height of the main frame section.②chassis rear overhang. The numerical impact of the General Assembly of Health cited the stability of dump truck, resulting in roll-over accident of Health cited. This value is normally between 500-1100 (except truck rollover).③ vehicle reasonable match, use and reliable.2、uploadDump Truck manufacturer modified the current cohabitation, choose the selection of dump truck manufacturers is equally important than the choice of products. In addition to look at products, but also the ability of equipment manufacturers, dump truck load of design, whether it is a mature technology and equipment, after-sales service commitment, whether or not to buy such accessories.附录B 英文文献翻译自卸车概述车厢配有自动倾卸装置的汽车。

机械设计制造及其自动化毕业论文中英文资料外文翻译

机械设计创造及其自动化毕业论文外文文献翻译INTEGRATION OF MACHINERY译文题目专业机械设计创造及其自动化外文资料翻译INTEGRATION OF MACHINERY（From ELECTRICAL AND MACHINERY INDUSTRY）ABSTRACTMachinery was the modern science and technology development inevitable result, this article has summarized the integration of machinery technology basic outline and the development background .Summarized the domestic and foreign integration of machinery technology present situation, has analyzed the integration of machinery technology trend of development.Key word： integration of machinery ，technology， present situation ，product t，echnique of manufacture ，trend of development0. Introduction modern science and technology unceasing development, impelled different discipline intersecting enormously with the seepage, has caused the project domain technological revolution and the transformation .In mechanical engineering domain, because the microelectronic technology and the computer technology rapid development and forms to the mechanical industry seepage the integration of machinery, caused the mechanical industry the technical structure, the product organization, the function and the constitution, the production method and the management systemof by machinery for the characteristic integration ofdevelopment phase.1. Integration of machinery outline integration of machinery is refers in the organization new owner function, the power function, in the information processing function and the control function introduces the electronic technology, unifies the system the mechanism and the computerization design and the software which constitutes always to call. The integration of machinery development also has become one to have until now own system new discipline, not only develops along with the science and technology, but also entrusts with the new content .But its basic characteristic may summarize is: The integration of machinery is embarks from the system viewpoint, synthesis community technologies and so on utilization mechanical technology, microelectronic technology, automatic control technology, computer technology, information technology, sensing observation and control technology, electric power electronic technology, connection technology, information conversion technology as well as software programming technology, according to the system function goal and the optimized organization goal, reasonable disposition and the layout various functions unit, in multi-purpose, high grade, redundant reliable, in the low energy consumption significance realize the specific function value, and causes the overall system optimization the systems engineering technology .From this produces functional system, then becomes an integration of machinery systematic or the integration of machinery product. Therefore, of coveringtechnology is based on the above community technology organic fusion one kind of comprehensive technology, but is not mechanical technical, the microelectronic technology as well as other new technical simple combination, pieces together .This is the integration of machinery and the machinery adds the machinery electrification which the electricity forms in the concept basic difference .The mechanical engineering technology has the merely technical to develop the machinery electrification, still was the traditional machinery, its main function still was replaces with the enlargement physical strength .But after develops the integration of machinery, micro electron installment besides may substitute for certain mechanical parts the original function, but also can entrust with many new functions,like the automatic detection, the automatic reduction information, demonstrate the record, the automatic control and the control automatic diagnosis and the protection automatically and so on .Not only namely the integration of machinery product is human's hand and body extending, human's sense organ and the brains look, has the intellectualized characteristic is the integration of machinery and the machinery electrification distinguishes in the function essence.2. Integration of machinery development condition integration of machinery development may divide into 3 stages roughly.20th century 60's before for the first stage, this stage is called the initial stage .In this time, the people determination not on own initiative uses the electronic technology the preliminary achievement to consummate the mechanical product the performance .Specially in Second World War period, the war has stimulated the mechanical product and the electronic technology union, these mechanical and electrical union military technology, postwar transfers civilly, to postwar economical restoration positive function .Developed and the development at that time generally speaking also is at the spontaneouscondition .Because at that time the electronic technology development not yet achieved certain level, mechanical technical and electronic technology union also not impossible widespread and thorough development, already developed the product was also unable to promote massively. The 20th century 70~80 ages for the second stage, may be called the vigorous development stage .This time, the computer technology, the control technology, the communication development, has laid the technology base for the integration of machinery development . Large-scale, ultra large scale integrated circuit and microcomputer swift and violent development, has provided the full material base for the integration of machinery development .This time characteristic is :①A mechatronics word first generally is accepted in Japan, probably obtains the quite widespread acknowledgment to 1980s last stages in the worldwide scale ;②The integration of machinery technology and the product obtained the enormous development ;③The various countries start to the integration of machinery technology and the product give the very big attention and the support. 1990s later periods, started the integration of machinery technology the new stagewhich makes great strides forward to the intellectualized direction, the integration of machinery enters the thorough development time .At the same time, optics, the communication and so on entered the integration of machinery, processes the technology also zhan to appear tiny in the integration of machinery the foot, appeared the light integration of machinery and the micro integration of machinery and so on the new branch; On the other hand to the integration of machinery system modeling design, the analysis and the integrated method, the integration of machinery discipline system and the trend of development has all conducted the thorough research .At the same time, because the hugeprogress which domains and so on artificial intelligence technology, neural network technology and optical fiber technology obtain, opened the development vast world for the integration of machinery technology .These research, will urge the integration of machinery further to establish the integrity the foundation and forms the integrity gradually the scientific system. Our country is only then starts from the beginning of 1980s in this aspect to study with the application .The State Councilsummary had considered fully on international the influence which and possibly brought from this about the integration of machinery technology developmenttrend .Many universities, colleges and institutes, the development facility and some large and middle scale enterprises have done the massive work to this technical development and the application, does not yield certain result, but and so on the advanced countries compared with Japan still has the suitable disparity.3. Integration of machinery trend of development integrations of machinery are the collection machinery, the electron, optics, the control, the computer, the information and so on the multi-disciplinary overlapping syntheses, its development and the progress rely on and promote the correlation technology development and the progress .Therefore, the integration of machinery main development direction is as follows:3.1 Intellectualized intellectualizations are 21st century integration of machinery technological development important development directions .Theartificial intelligence obtains day by day in the integration of machinery constructor's research takes, the robot and the numerical control engine bedis to the machine behavior description, is in the control theory foundation, the absorption artificial intelligence, the operations research, the computer science, the fuzzy mathematics, the psychology, the physiology and the chaos dynamics and so on the new thought, the new method, simulate the human intelligence, enable it to have abilities and so on judgment inference, logical thinking, independent decision-making, obtains the higher control goal in order to .Indeed, enable the integration of machinery product to have with the human identical intelligence, is not impossible, also is nonessential .But, the high performance, the high speed microprocessor enable the integration of machinery product to have preliminary intelligent or human's partial intelligences, then is completely possible and essential.In the modern manufacture process, the information has become the control manufacture industry the determining factor, moreover is the most active actuation factor .Enhances the manufacture system information-handling capacity to become the modern manufacture science development a key point .As a result of the manufacture system information organization and structure multi-level, makes the information the gain, the integration and the fusion presents draws up the character, information measure multi-dimensional, as well as information organization's multi-level .In the manufacture information structural model, manufacture information uniform restraint, dissemination processing and magnanimous data aspects and so on manufacture knowledge library management, all also wait for further break through.Each kind of artificial intelligence tool and the computation intelligence method promoted the manufacture intelligence development in the manufacture widespread application .A kind based on the biological evolution algorithm computation intelligent agent, in includes thescheduling problem in the combination optimization solution area of technology, receives the more and more universal attention, hopefully completes the combination optimization question when the manufacture the solution speed and the solution precision aspect breaks through the question scale in pairs the restriction .The manufacture intelligence also displays in: The intelligent dispatch, the intelligent design, the intelligent processing, the robot study, the intelligent control, the intelligent craft plan, the intelligent diagnosis and so on are various These question key breakthrough, may form the product innovation the basic research system. Between 2 modern mechanical engineering front science different science overlapping fusion will have the new science accumulation, the economical development and society's progress has had the new request and the expectation to the science and technology, thus will form the front science .The front science also has solved and between the solution scientific question border area .The front science has the obvious time domain, the domain and the dynamic characteristic .The project front science distinguished in the general basic science important characteristic is it has covered the key science and technology question which the project actual appeared.Manufacture system is a complex large-scale system, for satisfies the manufacture system agility, the fast response and fast reorganization ability, must profit from the information science, the life sciences and the social sciences and so on the multi-disciplinary research results, the exploration manufacture system new architecture, the manufacture pattern and the manufacture system effective operational mechanism .Makes the system optimization the organizational structure and the good movement condition is makes the system modeling , the simulation and the optimized essential target .Not only the manufacture system new architecture to makes the enterprise the agility and may reorganize ability to the demand response ability to have the vital significance, moreover to made the enterprise first floor production equipment the flexibility and may dynamic reorganization ability set a higher request .The biological manufacture view more and more many is introduced the manufacture system, satisfies the manufacture system new request.The study organizes and circulates method and technique of complicated system from the biological phenomenon, is a valid exit which will solve many hard nut to cracks that manufacturing industry face from now on currently .Imitating to living what manufacturing point is mimicry living creature organ of from the organization, from match more, from growth with from evolution etc. function structure and circulate mode of a kind of manufacturing system and manufacturing process.The manufacturing drives in the mechanism under, continuously by one's own perfect raise on organizing structure and circulating mode and thus to adapt the process of[with] ability for the environment .For from descend but the last product proceed together a design and make a craft rules the auto of the distance born, produce system of dynamic state reorganization and product and manufacturing the system tend automatically excellent provided theories foundation and carry out acondition .Imitate to living a manufacturing to belong to manufacturing science and life science of"the far good luck is miscellaneous to hand over", it will produce to the manufacturing industry for 21 centuries huge of influence .机电一体化摘要机电一体化是现代科学技术发展的必然结果,本文简述了机电一体化技术的基本概要和发展背景。

机械专业毕业设计外文翻译--振动的定义和术语

翻译：英文原文Definitions and Terminology of VibrationvibrationAll matter-solid, liquid and gaseous-is capable of vibration, e.g. vibration of gases occurs in tail ducts of jet engines causing troublesome noise and sometimes fatigue cracks in the metal. Vibration in liquids is almost always longitudinal and can cause large forces because of the low compressibility of liquids, e.g. popes conveying water can be subjected to high inertia forces (or “water hammer”) when a valve or tap is suddenly closed. Excitation forces caused, say by changes in flow of fluids orout-of-balance rotating or reciprocating parts, can often be reduced by attention to design and manufacturing details. Atypical machine has many moving parts, each of which is a potential source of vibration or shock-excitation. Designers face the problem of compromising between an acceptable amount of vibration and noise, and costs involved in reducing excitation.The mechanical vibrations dealt with are either excited by steady harmonic forces ( i. e. obeying sine and cosine laws in cases of forced vibrations ) or, after an initial disturbance, by no external force apart from gravitational force called weight ( i.e. in cases of natural or free vibrations). Harmonic vibrations are said to be “simple” if there is only one frequency as represented diagrammatically by a sine or cosine wave of displacement against time.Vibration of a body or material is periodic change in position or displacement from a static equilibrium position. Associated with vibration are the interrelated physical quantities of acceleration, velocity and displacement-e. g. an unbalanced force causes acceleration (a = F/m ) in a system which, by resisting, induces vibration as a response. We shall see that vibratory or oscillatory motion may be classified broadly as (a) transient; (b) continuing or steady-state; and (c) random.Transient Vibrations die away and are usually associated with irregulardisturbances, e. g. shock or impact forces, rolling loads over bridges, cars driven over pot holes-i. e. forces which do not repeat at regular intervals. Although transients are temporary components of vibrational motion, they can cause large amplitudes initially and consequent high stress but, in many cases, they are of short duration and can be ignored leaving only steady-state vibrations to be considered.Steady-State Vibrations are often associated with the continuous operation of machinery and, although periodic, are not necessarily harmonic or sinusoidal. Since vibrations require energy to produce them, they reduce the efficiency of machines and mechanisms because of dissipation of energy, e. g. by friction and consequentheat-transfer to surroundings, sound waves and noise, stress waves through frames and foundations, etc. Thus, steady-state vibrations always require a continuous energy input to maintain them.Random Vibration is the term used for vibration which is not periodic, i. e. has no made clear-several of which are probably known to science students already.Period, Cycle, Frequency and Amplitude A steady-state mechanical vibration is the motion of a system repeated after an interval of time known as the period. The motion completed in any one period of time is called a cycle. The number of cycles per unit of time is called the frequency. The maximum displacement of any part of the system from its static-equilibrium position is the amplitude of the vibration of that part-the total travel being twice the amplitude. Thus, “amplitude” is not synonymous with “displacement” but is the maximum value of the displacement from the static-equilibrium position.Natural and Forced Vibration A natural vibration occurs without any external force except gravity, and normally arises when an elastic system is displaced from a position of stable equilibrium and released, i. e. natural vibration occurs under the action of restoring forces inherent in an elastic system, and natural frequency is a property of he system.A forced vibration takes place under the excitation of an external force (or externally applied oscillatory disturbance) which is usually a function of time, e. g.in unbalanced rotating parts, imperfections in manufacture of gears and drives. The frequency of forced vibration is that of the exciting or impressed force, i. e. the forcing frequency is an arbitrary quantity independent of the natural frequency of the system.Resonance Resonance describes the condition of maximum amplitude. It occurs when the frequency of an impressed force coincides with, or is near to a natural frequency of the system. In this critical condition, dangerously large amplitudes and stresses may occur in mechanical systems but, electrically, radio and television receivers are designed to respond to resonant frequencies. The calculation or estimation of natural frequencies is, therefore, of great importance in all types of vibrating and oscillating systems. When resonance occurs in rotating shafts and spindles, the speed of rotation is known as the critical speed. Hence, the prediction and correction or avoidance3 of a resonant condition in mechanisms is of vital importance since, in the absence of damping or other amplitude-limiting devices, resonance is the condition at which a system gives an infinite response to a finite excitation.Damping Damping is the dissipation of energy from a vibrating system, and thus prevents excessive response. It is observed that a natural vibration diminishes in amplitude with time and, hence, eventually ceases owing to some restraining or damping influence. Thus if a vibration is to be sustained, the energy dissipated by damping must be replaced from an external source.The dissipation is related in some way to the relative motion between the components or elements of the system, and is caused by frictional resistance of some sort, e.g. in structures, internal friction in material, and external friction caused by air or fluid resistance called “viscous” damping if the drag force is assumed proportional to the relative velocity between moving parts. One device assumed to give viscous damping is the “dashpot” which is a loosely fitting piston in a cylinder so that fluid can flow from one side of the piston to the other through the annular clearance space.A dashpot cannot store energy but can only dissipate it.Basic Machining Operations and Machine ToolsBasic Machining OperationsMachine tools have evolved from the early foot-powered lathes of the Egyptians and John Wilkinson’s boring mill. They are designed to provide rigid support for both the workpiece and the cutting tool and can precisely control their relative positions and the velocity of the tool with respect to the workpiece. Basically, in metal cutting, a sharpened wedge-shaped tool removes a rather narrow strip of metal from the surface of a ductile workpiece in the form of a severely deformed chip. The chip is a waste product that is comsiderably shorter than the workpiece from which it came but woth a corresponding increase in thickness of the uncut chip. The geometrical shape of the machine surface depedns on the shape of the tool and its path during the machinig operation.Most machining operations produce parts of differing geometry. If a rough cylindrical workpiece revolves about a central axis and the tool penetrates beneath its surface and travels parallel to the center of rotation, a surface of revolution is producedand the operation is called turning. If a hollow tube is machined on the inside in a similar manner, the operation is called boring. Producing an external conical surface of uniformly varying diameter is called taper turning. If the tool point travels in a path of varying radius,a contoured surface like that of a bowling pin a can be produced; or, if the piece is short enough and the support is sufficiently rigid, a contoured surface could be produced by feeding a shaped tool normal to the axis of rotation. Short tapered or cylindrical surfaces could also be contour formed.Flat or plane surfaces are frequently required. The can be generated by adial turning or facing, in which the tool point moves normal to the axis of rotation. In other cases, it is more convenient to hold the workpiece steady and reciprocate the tool across it in a series of straight-line cuts with a crosswise feed increment before each cutting stroke. This operation is called planing and is carried out on a shaper. For larger pieces it is easier to keep the tool stationary and draw the workpiece under it as inplaning. The tool is fed at each reciprocation. Contoured surfaces can be produced by using shaped tools.Multiple-edged tools can also be used. Drilling uses a twin-edged fluted tool for holes with depths up to 5 10times the drill diameter. Whether the dril turns or the workpiece rotates, relative motion between the cutting edge and the workpiece is the important factor. In milling operations a rotary cutter with a number of cutting edges engages the workpiecem which moves slowly with respect to the cutter. Plane or contoured surfaces may be produced, depending on the geometry of the cutter and the type of feed. Horizontal or vertical axes of rotation ma be used, and the feed of the workpiece may be in any of the three coordinate directions.Basic Machine ToolsMachine tools are used to produce a part of a specified geometrical shape and precise size by removing metal from a ductile materila in the form of chips. The latter are a waste product and vary from long continuous ribbons of a ductile material such as steel, which are undesirable from a disposal point of view, to easily handled well-broken chips resulting from cast iron. Machine tools perform five basic metal-removal processes: turning, planing, drilling, milling, and frinding. All other metal-removal processes are modifications of these five basic processes. For example, boring is internal turning;reaming,tapping, and counterboring modify drilled holes and are related to drilling; hobbing and gear cutting are fundamentally milling operations; hack sawong and broaching are a form of planing and honing; lapping, superfinishing, polishing, and buffing are avariants of grinding or abrasive removal operations. Therefore, there are only four types of basic machine tools, which use cutting tools of specific controllable feometry: thes, 2.planers, 3.drilling machines, and ling machines. The frinding process forms chips, but the geometry of the barasive grain is uncontrollable.The amount and rate of material removed by the various machining processes may be large, as in heavy truning operations, or extremely small, as in lapping or superfinishing operations where only the high spots of a surface are removed.A machine tool performs three major functions: 1.it rigidly supports the workpiece orits holder and the cutting tool; 2. it provedes relative motion between the workpiece and the cutting tools; 3. it provides a range of feeds and speeds usually ranging from 4 to 32 choices in each case.Speed and Feeds in MachiningSpeeds feeds, and depth of cut are the three major variables for economical machining. Other variables are the work and tool materials, coolant and geometry of the cutting tool. The rate of metal removal and power required for machining depend upon these variables.The depth of cut, feed, and cutting speed are machine settings that must be established in any metal-cutting operation. They all affect the forces, the power, and the rate of metal removal. They can be defined by comparing them to the needle and record of a phonograph. The cutting speed is represented by the velocity of the record surface relative to the needle in the tone arm at any instant. Feed is represented by the advance the needle radially inward per revolution, or is the difference in position between two adjacent grooves.Turning on Lathe CentersThe basic operations performed on an engine lathe are illustrated in Fig. Those operations performed on extemal surfaces with a single point cutting tool are called turning. Except for drilling, reaming, and tapping, the operations on intermal surfaces are also performed by a single point cutting tool.All machining operations, including turning and boring, can be classified as roughing, finishing, or semi-finishing. The objective of a roughing ooperation is to remove the bulk of the material sa repidly and as efficiently as possible, while leaving a small amount of material on the work-piece for the finishing operation. Finishing operations are performed to btain the final size, shape, and surface finish on the workpiece. Sometimes a semi-finishing operation will precede the finishing operation to leave a small predetermined and uniform amount of stoxd on the work-piece to be removed by the finishing operation.Generally, longer workpieces are turned while supported on one or two lathe centers. Cone shaped holes, called center holes, which fit the lathe centers are drilled in the ends of the workpiece-usually along the axis of the cylindrical part. The end of the workpiece adjacent to the tailstock is always supported by a tailstock center, while the end near the headstock may be supported by a headstock cener or held in a chuck. The headstock end of the workpiece may be held in a four-jar chuck, or in a collet type chuck. This method holds the workpiece firmly and transfers the power to the workpiece smoothly; the additional support to the workpiece priovided by the chuck lessens the tendency for chatter to occur when cutting. Precise results can be obtained with this method if care is taken to hold the workpiece accurately in the chuck.Very precise results can be obtained by supporting the workpiece between two centers.A lathe dog is clamped to the workpiece; together they are driven by a driver p;ate mounted on the spindle nose. One end of the workpiece is machined; then the workpiece can be turned around in the lathe to machine the other end. The center holes in the workpiece serve as precise locating surfaces as well as bearing surfaces to carry the weight of the workpiece and to resist the xutting forces. After the workpiece has been removed from the lathe for any reason, the center holes will accurately align the workpiece back in the lathe or in another lathe,or in a cylindrical grinding machine. The workpiece must never be held at the headstock end by both a chuck and a lathe center. While at first thought this seems like a quick method of aligning the workpiece in the chuck, this must not be done because it is not possible to press evenly with the jaws against the workpiece while it is also supported by the center. The alignment provided by the center will not be maintained and the pressure of the jaws may damage the center hole, the lathe center,and prehaps even the lathe spindle. Compensatng or floating jaw chucks used almost exclusively on high production work provice an exception to the statements made above. These chucks are really work drivers and cannot be used for the same purpose as ordinary three or four=jaw chucks. While very large diameter workpieces are sometimes mounted on two centers, they are preferably held at the headstock end by faceplate jaes to obtain the smooth power transmission; moreover, large lathe dogs that are adequate to transmit the power notgenerally available, although they can be maed as a special. Faceplate jaws are like chuck jaws except that thet are mounted on a faceplate, which has less overhang from the spindle bearings than a large chuck would have.BoringThe boring operation is generally performed in two steps; namely, rough boring and finish boring. The objective of the rough-boring operation is to remove the excess metal rapidly and efficiently, and the objective of the finish-boring operation is to obtain the desired size, surface finish, and location of the hole. The size of the hole is obtained by using the trial-cut procedure. The diameter of the hole can be measured with inside calipers and outside micrometer calipers. Basic Measuring Insteruments, or inside micrometer calipers can be used to measure the diameter directly.Cored holes and drilled holes are sometimes eccentric wwith respect to the rotation of the lathe. When the boring tool enters the work, the boring bar will take a deeper cut on one side of the hole than on the other, and will deflect more when taking this deeper cut,with the result that the bored hole will not be concentric with the rotation of the work. This effect is corrected by taking several cuts through the hole using a shallow depth of cut. Each succeeding shallow cut causes the resulting hole to be more concentric than it was with the previous cut. Before the final, finish cut is taken, the hole should be concentric with the rotation of the work in order to make certain that the finished hole will be accurately located.Shoulders, grooves, contours, tapers, and threads are bored inside of holes. Internal grooves are cut using a tool that is similar to an external grooving tool. The procedure for boring internal shoulders is very similar to the procedure for turning rge shoulders are faced with the boring tool positioned with the nose leading, and using the cross slide to feed the tool. Internal contours can be machined using a tracing attachment on a lathe. The tracing attachment is mounted on the cross slide and the stylus follows the outline of the master profile plate. This causes the cutting tool to move in a path corresponding to the profile of the master profile plate.Thus, the profile on the master profile plate is reproduced inside the bore. The master profile plate is accurately mounted on a special slide which can be precisely adjusted in two dirctions, in two directionsm, in order to align the cutting tool in the correct relationship to the work. This lathe has a cam-lick type of spindle nose which permits it to take a cut when rotating in either direction. Normal turning cuts are taken with the spindle rotating counterclockwise. Thie boring cut is taken with the spindle revolving in a clockwise direction, or “backwards”. This permits the boring cut to be taken on the “back side” of the bore which is easier to see from the operator’sposition in front of the lathe. This should not be done on lathes having a threaded spindle nose because the cutting force will tend to unscrew the chuck.中文翻译振动的定义和术语振动所有的物质---固体，液体和气体-----都能够振动，例如，在喷气发动机尾部导管中产生的气体振动会发出令人讨厌的噪声，而且有时还会使金属产生疲劳裂缝。

机械毕业设计外文翻译---数控机床

What Is CNCCNC stands for Computer Numerical Control and has been around since the early 1970''s. Prior to this, it was called NC, for Numerical Control. (In the early 1970''s, computers were introduced in these controls, hence the name changed)While people in most walks of life have never heard of this term, CNC has touched almost every form of manufacturing process in one way or another. If you''ll be working in manufacturing, it''s likely that you''ll be dealing with CNC on a regular basis.Before CNCWhile there are exceptions to this statement, CNC machines typically replace (or work in conjunction with) some existing manufacturing process/es. Take one of the simplest manufacturing processes, drilling holes, for example.A drill press can of course be used to machine holes. (It''s likely that almost everyone has seen some form of drill press, even if you don''t work in manufacturing.) A person can place a drill in the drill chuck that is secured in the spindle of the drill press. They can then (manually) select the desired speed for rotation (commonly by switching belt pulleys), and activate the spindle. Then they manually pull on the quill lever to drive the drill into the workpiece being machined.As you can easily see, there is a lot of manual intervention required to use a drill press to drill holes. A person is required to do something almost every step along the way! While this manual intervention may be acceptable for manufacturing companies if but a small number of holes or workpieces must be machined, as quantities grow, so does the likelihood for fatigue due to the tediousness of the operation. And do note that we''ve used one of the simplest machining operations (drilling) for our example. There are more complicated machining operations that would require a much higher skill level (and increase the potential for mistakes resulting in scrap workpieces) of the person running the conventional machine tool. (We commonly refer to the style of machine that CNC is replacing as the conventional machine.)By comparison, the CNC equivalent for a drill press (possibly a CNC machining center or CNC drilling & tapping center) can be programmed to perform this operation in a much more automatic fashion. Everything that the drill press operator was doing manually will now be done by the CNC machine, including: placing the drill in the spindle, activating the spindle, positioning the workpiece under the drill, machining the hole, and turning off the spindle.How CNC worksThere is another article included in this web site called The Basics of CNC that explains how to program, setup, and operate CNC machines in greater detail. Additionally, we offer a series of products aimed at helping you learn how to use CNC machines. Here we''re relating how CNC works in very general terms.As you might already have guessed, everything that an operator would be required to do with conventional machine tools is programmable with CNC machines. Once the machine is setup and running, a CNC machine is quite simple to keep running. In fact CNC operators tend to get quite bored during lengthy production runs because there is so little to do. With some CNC machines, even the workpiece loading process has been automated. (We don''t mean toover-simplify here. CNC operators are commonly required to do other things related to the CNC operation like measuring workpieces and making adjustments to keep the CNC machine running good workpieces.)Let''s look at some of the specific programmable functions.Motion controlAll CNC machine types share this commonality: They all have two or more programmable directions of motion called axes. An axis of motion can be linear (along a straight line) or rotary (along a circular path). One of the first specifications that implies a CNC machine''s complexity is how many axes it has. Generally speaking, the more axes, the more complex the machine.The axes of any CNC machine are required for the purpose of causing the motions needed for the manufacturing process. In the drilling example, these (3) axis would position the tool over the hole to be machined (in two axes) and machine the hole (with the third axis). Axes are named with letters. Common linear axis names are X, Y, and Z. Common rotary axis names are A, B, and C.Programmable accessoriesA CNC machine wouldn''t be very helpful if all it could only move the workpiece in two or more axes. Almost all CNC machines are programmable in several other ways. The specific CNC machine type has a lot to do with its appropriate programmable accessories. Again, any required function will be programmable on full-blown CNC machine tools. Here are some examples for one machine type.Machining centersAutomatic tool changerMost machining centers can hold many tools in a tool magazine. When required, the required tool can be automatically placed in the spindle for machining.Spindle speed and activationThe spindle speed (in revolutions per minute) can be easily specified and the spindle can be turned on in a forward or reverse direction. It can also, of course, be turned off.CoolantMany machining operations require coolant for lubrication and cooling purposes. Coolant can be turned on and off from within the machine cycle.The CNC programThink of giving any series of step-by-step instructions. A CNC program is nothing more than another kind of instruction set. It''s written in sentence-like format and the control will execute it in sequential order, step by step.A special series of CNC words are used to communicate what the machine is intended to do. CNC words begin with letter addresses (like F for feedrate（馈送率）, S for spindle speed, and X, Y & Z for axis motion). When placed together in a logical method, a group of CNC words make up a command that resemble a sentence.For any given CNC machine type, there will only be about 40-50 words used on a regular basis. So if you compare learning to write CNC programs to learning a foreign language having only50 words, it shouldn''t seem overly difficult to learn CNC programming.The CNC controlThe CNC control will interpret a CNC program and activate the series of commands in sequential order. As it reads the program, the CNC control will activate the appropriate machine functions, cause axis motion, and in general, follow the instructions given in the program.Along with interpreting the CNC program, the CNC control has several other purposes. All current model CNC controls allow programs to be modified (edited) if mistakes are found. The CNC control allows special verification functions (like dry run) to confirm the correctness of the CNC program. The CNC control allows certain important operator inputs to be specified separate from the program, like tool length values. In general, the CNC control allows all functions of the machine to be manipulated.What is a CAM system?For simple application (like drilling holes), the CNC program can be developed manually. That is, a programmer will sit down to write the program armed only with pencil, paper, and calculator. Again, for simple applications, this may be the very best way to develop CNC programs.As applications get more complicated, and especially when new programs are required on a regular basis, writing programs manually becomes much more difficult. To simplify the programming process, a computer aided manufacturing (CAM) system can be used. A CAM system is a software program that runs on a computer (commonly a PC) that helps the CNC programmer with the programming process. Generally speaking, a CAM system will take the tediousness and drudgery out of programming.What is a DNC system?Once the program is developed(either manually or with a CAM system), it must be loaded into the CNC control. Though the setup person could type the program right into the control, this would be like using the CNC machine as a very expensive typewriter. If the CNC program is developed with the help of a CAM system, then it is already in the form of a text file . If the program is written manually, it can be typed into any computer using a common word processor (though most companies use a special CNC text editor for this purpose). Either way, the program is in the form of a text file that can be transferred right into the CNC machine. A distributive numerical control (DNC) system is used for this purpose.A DNC system is nothing more than a computer that is networked with one or more CNC machines. Until only recently, rather crude serial communications protocol (RS-232c) had to be used for transferring programs. Newer controls have more current communications capabilities and can be networked in more conventional ways (Ethernet, etc.). Regardless of methods, the CNC program must of course be loaded into the CNC machine before it can be run.中文翻译：什么数控机床数控机床代表计算机数字控制机床，并且从20世纪70年代以来一直受到人们的关注。

机械专业毕业设计--外文资料和翻译

Metal heat treatmentA, annealingIn front of the description lengba processing materials and softening plastic treatment methods, it has been used the word, the word annealing with similar meanings. The purpose is to reduce completely annealing, hardness, plastic, sometimes also increased to improve the cutting performance, high this steel is difficult to processing. This method is used to reduce heat stress, refined grains, improve the structure of the material.Annealing is not always can improve the cutting machining, cutting processing a word used to describe several factors, including material cutting when good finish (i.e. smaller surface roughness - the ability of the translator. When fully annealing, ordinary low hardness, low intensity of cutting resistance smaller, less, but usually due to the plasticity and toughness is too big to chip away when the surface of workpiece surface of workpiece surface quality, scratch, leads to poor cutting processing. For this kind of steel, annealing may not be the most appropriate treatment. Many of the most high and cutting steel processing usually can be greatly improved by annealing except in the soft, because of their condition, high hardness and strength for processing.And the annealing method is GongXi just slow to the steel wire, insulation above about for a period of time, make the same temperature uniformity, forming materials, then the austenitic or buried with furnace lime or other insulating materials in slow cooling. To precipitation of ferrite and pearlite bulky iron, steel in the soft, the strain of toughness and minimum, must slow cooling.Second, normalizingHow much is the fire of similar purposes, but not the annealing steel soft and fine pearlite state. Not bulky. Steel is refined grains, fire can release of stress, improve structural homogeneity and restore some plastic, high toughness. This method is often used to improve cutting machining, reduce stress, reduce part machining or limitation of deformation.Is the fire will chromatography method is GuoGongXiGang steel or slow heatedto Ac3 respectively, Accm line or on-line insulation for a period of time to form, and in the austenitic stationary air slow cooling. Should notice more, GongXi composition of carbon steel needs to be heated to Accm line above, not Ac1 line above the annealing. The purpose is in the process of austenitic to dissolve all cementite, thus to minimize the boundaries on hard and brittle iron carbon compounds, and get little grain of ferrite pearlite, minimum free cementite and freedom.Third, the ball annealingThrough the steel ball annealing can get minimum hardness and the biggest plastic, it can make the iron carbon compounds with small globular distribution in ferritic matrix. In order to make the ball easier small particles, usually for fire steel ball annealing. Ball annealing available in several different methods, but all the methods are needed in A1 line near (usually slightly low temperature preservation) for a long time, make the iron carbon compounds formed more stable, low level of small ball.Ball annealing method of the main objective is to improve the cutting processing, and drawing of hardened steel pretreatment, make it more uniform structure quenching. Because of the heat treatment for a long time, so the cost is higher than that of ball annealing is common or annealing.Four, steel sclerosisThe most hardened steel heat treatment method is based on the production of martensite high. Therefore, the first step to most other treatment with commonly used method -- austenitic. YaGongXiGang heated to Ac1 liquidus temperature, heat preservation, more about that temperature uniformly, austenitic evenly. GuoGongXiGang Ac1 above liquidus temperature preservation in steel, while about still remain iron carbon compounds.The second step is to avoid rapid cooling in the nose produces isothermal curve transformation pearlite. The cooling speed depends on the temperature and hardened steel quenching medium heat can be taken away from the surface of the ability of heat transfer and steel itself. Table 1-11 is some common medium and cooling method, cooling ability of the sequence.High temperature gradient produces high stress, deformation and cracking causes,so only in the very need to produce quenching specific structures are used. When the quenching heat uniform, care must be taken to reduce the heat stress diffusion. For example, a thin stick to end its vertical quenching, is inserted into the cooling medium, so whole section and temperature changes. If the shape of a side of the workpiece cooling, and on the other side of the earlier than size change is likely to cause high stress, produce plastic flow and permanent deformation.With several special quenching method can reduce stress, deformation and cracking quenching decreases. One called hierarchical quenching, the method is: will the austenitic steel in temperature is higher than that of martensite transformation temperature (Ms), salt bath time until the temperature uniformity, at the beginning of forming bainite, then put before air cooling, heat generated from the start when the same hardware quenching cracking, martensite and warpage cause of high thermal stress or eliminate stress have been quenched.In a similar method of temperature, then, is called the isothermal quenching (austenitic steel in salt bath), keep for a long time, the result is formed with the isothermal bainite. Bainite structure in the same ingredients as the formation of martensite hard, but in normal hardened steel, reduce the heat shock, by further processing, unnecessary in high hardness can be obtained when good impact toughness.Five, temperingTo adjust hardened steel used the third step is often backfire. Besides the isothermal quenching steel quenching condition usually used in most all can use in production. To produce martensite steel to quench make hard, macro and micro stress, stress, low plasticity materials. To reduce the harm that can be heated to steel again by low-temperature shift (A1) below a certain temperature. Hardened steel structure change of tempering time and temperature is the function of temperature, which is the most important. Must be hardened piece.it is emphasized, method, but the reverse is true. Steel is tempered by heat treatment of hardened steel, through the tempering of heating, to release stress again, soften and improve plastic.The structural change and tempering causes change depending on performance of the heating temperature steel back. The higher the temperature, the temperatureeffect, so the choice is often sacrificed for the hardness and strength plasticity and toughness. Again, to quench heating to influence of carbon-steel, in between, structure, changes will occur in the above, the structure and properties of the significant changes. In the next time the temperature of the A1 heat will produce and process of ball annealing of similar structures.In industry, usually avoid to scope, because the tempering within the scope of tempering steel often produced unexplained brittleness or plastic loss. Some alloy in to scope, also can produce "temper brittleness, especially from" (or by) the temperature range slow cooling will appear. When these steel heat temper, they must usually heated to rapid cooling and above. Of course, from the temperature of cold won't produce sclerosis, fast because no austenitic.金属热处理一、退火在前面描述冷拔加工材料的软化并重新获得塑性的热处理方法时，就已使用退火这个词，该词具有相似的意义。

机械毕业设计英文外文翻译213机械设计基础

附录(外文翻译——原文)Fundamentals of Mechanical DesignMechanical design means the design of things and systems of a mechanical nature—machines, products, structures, devices, and instruments. For the most part mechanical design utilizes mathematics, the materials sciences, and the engineering-mechanics sciences.The total design process is of interest to us. How does it begin? Does the engineer simply sit down at his desk with a blank sheet of paper? And, as he jots down some ideas, what happens next? What factors influence or control the decisions which have to be made? Finally, then, how does this design process end?Sometimes, but not always, design begins when an engineer recognizes a need and decides to do something about it. Recognition of the need and phrasing it in so many words often constitute a highly creative act because the need may be only a vague discontent, a feeling of uneasiness, of a sensing that something is not right.The need is usually not evident at all. For example, the need to do something about a food-packaging machine may be indicated by the noise level, by the variations in package weight, and by slight but perceptible variations in the quality of the packaging or wrap.There is a distinct difference between the statement of the need and the identification of the problem. which follows this statement. The problem is more specific. If the need is for cleaner air, the problem might be that of reducing the dust discharge from power-plant stacks, or reducing the quantity of irritants from automotive exhausts.Definition of the problem must include all the specifications for the thing that is to be designed. The specifications are the input and output quantities, the characteristics of the space the thing must occupy and all the limitations on these quantities. We can regard the thing to be designed as something in a black box. In this case we must specify the inputs and outputs of the box together with their characteristics and limitations. The specifications define the cost, the number to be manufactured, the expected life, the range, the operating temperature, and the reliability.There are many implied specifications which result either from the designer's particular environment or from the nature of the problem itself. The manufacturing processes which are available, together with the facilities of a certain plant, constitute restrictions on a designer's freedom, and hence are a part of the implied specifications. A small plant, for instance, may not own cold-working machinery. Knowing this, the designer selects other metal-processing methods which can be performed in the plant. The labor skills available and the competitive situation also constitute implied specifications.After the problem has been defined and a set of written and implied specifications has been obtained, the next step in design is the synthesis of an optimum solution. Now synthesis cannot take place without both analysis and optimization because the system under design must be analyzed to determine whether the performance complies with the specifications.The design is an iterative process in which we proceed through several steps, evaluate theresults, and then return to an earlier phase of the procedure. Thus we may synthesize several components of a system, analyze and optimize them, and return to synthesis to see what effect this has on the remaining parts of the system. Both analysis and optimization require that we construct or devise abstract models of the system which will admit some form of mathematical analysis. We call these models mathematical models. In creating them it is our hope that we can find one which will simulate the real physical system very well.Evaluation is a significant phase of the total design process. Evaluation is the final proof of a successful design, which usually involves the testing of a prototype in the laboratory. Here we wish to discover if the design really satisfies the need or needs. Is it reliable? Will it compete successfully with similar products? Is it economical to manufacture and to use? Is it easily maintained and adjusted? Can a profit be made from its sale or use?Communicating the design to others is the final, vital step in the design process. Undoubtedly many great designs, inventions, and creative works have been lost to mankind simply because the originators were unable or unwilling to explain their accomplishments to others. Presentation is a selling job. The engineer, when presenting a new solution to administrative, management, or supervisory persons, is attempting to sell or to prove to them that this solution is a better one. Unless this can be done successfully, the time and effort spent on obtaining the solution have been largely wasted.Basically, there are only three means of communication available to us. There are the written, the oral, and the graphical forms. Therefore the successful engineer will be technically competent and versatile in all three forms of communication. A technically competent person who lacks ability in any one of these forms is severely handicapped. If ability in all three forms is lacking, no one will ever know how competent that person is!The competent engineer should not be afraid of the possibility of not succeeding in a presentation. In fact, occasional failure should be expected because failure or criticism seems to accompany every really creative idea. There is a great to be learned from a failure, and the greatest gains are obtained by those willing to risk defeat. In the find analysis, the real failure would lie in deciding not to make the presentation at all.Introduction to Machine DesignMachine design is the application of science and technology to devise new or improved products for the purpose of satisfying human needs. It is a vast field of engineering technology which not only concerns itself with the original conception of the product in terms of its size, shape and construction details, but also considers the various factors involved in the manufacture, marketing and use of the product.People who perform the various functions of machine design are typically called designers, or design engineers. Machine design is basically a creative activity. However, in addition to being innovative, a design engineer must also have a solid background in the areas of mechanical drawing, kinematics, dynamics, materials engineering, strength of materials and manufacturing processes.As stated previously, the purpose of machine design is to produce a product which will serve a need for man. Inventions, discoveries and scientific knowledge by themselves do not necessarily benefit people; only if they are incorporated into a designed product will a benefit be derived. It should be recognized, therefore, that a human need must be identified before a particular product is designed.Machine design should be considered to be an opportunity to use innovative talents to envision a design of a product is to be manufactured. It is important to understand the fundamentals of engineering rather than memorize mere facts and equations. There are no facts or equations which alone can be used to provide all the correct decisions to produce a good design. On the other hand, any calculations made must be done with the utmost care and precision. For example, if a decimal point is misplaced, an otherwise acceptable design may not function.Good designs require trying new ideas and being willing to take a certain amount of risk, knowing that is the new idea does not work the existing method can be reinstated. Thus a designer must have patience, since there is no assurance of success for the time and effort expended. Creating a completely new design generally requires that many old and well-established methods be thrust aside. This is not easy since many people cling to familiar ideas, techniques and attitudes. A design engineer should constantly search for ways to improve an existing product and must decide what old, proven concepts should be used and what new, untried ideas should be incorporated.New designs generally have “bugs” or unforeseen problems which mu st be worked out before the superior characteristics of the new designs can be enjoyed. Thus there is a chance for a superior product, but only at higher risk. It should be emphasized that, if a design does not warrant radical new methods, such methods should not be applied merely for the sake of change.During the beginning stages of design, creativity should be allowed to flourish without a great number of constraints. Even though many impractical ideas may arise, it is usually easy to eliminate them in the early stages of design before firm details are required by manufacturing. In this way, innovative ideas are not inhibited. Quite often, more than one design is developed, up to the point where they can be compared against each other. It is entirely possible that the design which ultimately accepted will use ideas existing in one of the rejected designs that did not show as much overall promise.Psychologists frequently talk about trying to fit people to the machines they operate. It is essentially the responsibility of the design engineer to strive to fit machines to people. This is not an easy task, since there is really no average person for which certain operating dimensions and procedures are optimum.Another important point which should be recognized is that a design engineer must be able to communicate ideas to other people if they are to be incorporated. Initially the designer must communicate a preliminary design to get management approval. This is usually done by verbal discussions in conjunction with drawing layouts and written material. To communicate effectively, the following questions must be answered:(1)Does the design really serve a human need?(2)Will it be competitive with existing products of rival companies?(3)Is it economical to produce?(4)Can it be readily maintained?(5)Will it sell and make a profit?Only time will provide the true answers to the preceding questions, but the product should be designed, manufactured and marketed only with initial affirmative answers. The design engineer also must communicate the finalized design to manufacturing through the use of detailand assembly drawings.Quite often, a problem well occur during the manufacturing cycle. It may be that a change is required in the dimensioning or tolerancing of a part so that it can be more readily produced. This falls in the category of engineering changes which must be approved by the design engineer so that the product function will not be adversely affected. In other cases, a deficiency in the design may appear during assembly or testing just prior to shipping. These realities simply bear out the fact that design is a living process. There is always a better way to do it and the designer should constantly strive towards finding that better way.MachiningTurning The engine lathe, one of the oldest metal removal machines, has a number of useful and highly desirable attributes. Today these lathes are used primarily in small shops where smaller quantities rather than large production runs are encountered.The engine lathe has been replaced in today's production shops by a wide variety of automatic lathes such as automatic of single-point tooling for maximum metal removal, and the use of form tools for finish and accuracy, are now at the designer's fingertips with production speeds on a par with the fastest processing equipment on the scene today.Tolerances for the engine lathe depend primarily on the skill of the operator. The design engineer must be careful in using tolerances of an experimental part that has been produced on the engine lathe by a skilled operator. In redesigning an experimental part for production, economical tolerances should be used.Turret Lathes Production machining equipment must be evaluated now, more than ever before, in terms of ability to repeat accurately and rapidly. Applying this criterion for establishing the production qualification of a specific method, the turret lathe merits a high rating.In designing for low quantities such as 100 or 200 parts, it is most economical to use the turret lathe. In achieving the optimum tolerances possible on the turret lathe, the designer should strive for a minimum of operations.Automatic Screw Machines Generally, automatic screw machines fall into several categories; single-spindle automatics, multiple-spindle automatics and automatic chucking machines. Originally designed for rapid, automatic production of screws and similar threaded parts, the automatic screw machine has long since exceeded the confines of this narrow field, and today plays a vital role in the mass production of a variety of precision parts. Quantities play an important part in the economy of the parts machined on the automatic to set up on the turret lathe than on the automatic screw machine. Quantities less than 1000 parts may be more economical to set up on the turret lathe than on the automatic screw machine. The cost of the parts machined can be reduced if the minimum economical lot size is calculated and the proper machine is selected for these quantities.Automatic Tracer Lathes Since surface roughness depends greatly upon material turned, tooling ,and fees and speeds employed, minimum tolerances that can be held on automatic tracer lathes are not necessarily the most economical tolerances.Is some case, tolerances of ±0.05mm are held in continuous production using but one cut. Groove width can be held to ±0.125mm on some parts. Bores and single-point finishes can be held to ±0.0125mm. On high-production runs where maximum output is desirable, a minimum tolerance of ±0.125mm is economical on both diameter and length of turn.Milling With the exceptions of turning and drilling, milling is undoubtedly the most widely used method of removing metal. Well suited and readily adapted to the economical production of any quantity of parts, the almost unlimited versatility of the milling process merits the attention and consideration of designers seriously concerned with the manufacture of their product.As in any other process, parts that have to be milled should be designed with economical tolerances that can be achieved in production milling. If the part is designed with tolerances finer than necessary, additional operations will have to be added to achieve these tolerances——and this will increase the cost of the part.Grinding Grinding is one of the most widely used methods of finishing parts to extremely close tolerances and low surface roughness. Currently, there are grinders for almost for almost every type of grinding operation. Particular design features of a part dictate to a large degree the type of grinding machine required. Where processing costs are excessive, parts redesigned to utilize a less expensive, higher output grinding method may be well worthwhile. For example, wherever possible the production economy of centerless grinding should be taken advantage of by proper design consideration.Although grinding is usually considered a finishing operation, it is often employed as a complete machining process on work which can be ground down from rough condition without being turned or otherwise machined. Thus many types of forgings and other parts are finished completely with the grinding wheel at appreciable savings of time and expense.Classes of grinding machines include the following: cylindrical grinders, centerless grinders, internal grinders, surface grinders, and tool and cutter grinders.The cylindrical and centerless grinders are for straight cylindrical or taper work; thus splines, shafts, and similar parts are ground on cylindrical machines either of the common-center type or the centerless machine.Thread grinders are used for grinding precision threads for thread gages, and threads on precision parts where the concentricity between the diameter of the shaft and the pitch diameter of the thread must be held to close tolerances.The internal grinders are used for grinding of precision holes, cylinder bores, and similar operations where bores of all kinds are to be finished.The surface grinders are for finishing all kinds of flat work, or work with plain surfaces which may be operated upon either by the edge of a wheel or by the face of a grinding wheel. These machines may have reciprocating or rotating tables.(外文翻译——汉文)机械设计基础机械设计基础是指机械装置和机械系统——机器、产品、结构、设备和仪器的设计。

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襄樊学院毕业设计(论文)英文翻译题目超声波简介及其应用专业机械设计制造及其自动化班级机制0712姓名刘康学号07116201指导教师职称李梅副教授2011年5月25日Introduction and application of ultrasonic Ultrasonic is a mechanical waves which frequency above 20,000 Hz. Ultrasonic inspection commonly used in the frequency of 0. 5~5 MHz. The mechanical waves in the material spread in a certain speed and directions, acoustic impedance different heterogeneous interfaces such as defect is encountered or the bottom surface of the object being tested, will reflections. This reflection phenomenon can be used to ultrasonic testing , most common is pulse echo testing method testing , pulse oscillator issued of voltage plus in probe with pressure electric ceramic or quartz chip made of detection components , probe issued of ultrasonic pulse by sound coupled media such as oil or water , entered material and in which spread , encountered defects , part reflection energy along original way returns probe , probe will change it in electric pulse , by instrument zoom and display in oscilloscope tubes of screen . Depending on where the flaw echo on the screen and amplitude of reflection wave with artificial defects in a reference block rate compared to defect location and approximate dimensions. Apart from Echo method, and use another probe to the other side of the workpiece to accept signal penetration method. When use ultrasonic detection the physical properties of materials, also often take advantage of ultrasonic in sound velocity, attenuation and resonance characteristics of workpiece.Ultrasonic characteristics: 1, ultrasonic beam to focus on a specific direction, along the straight lines in the media, has a good point. 2, ultrasonic wave propagation in the media, attenuation and scattering occurs. 3, ultrasonic wave on the interface of heterogeneous media will make reflection, refraction and mode conversion. Using these features, you can get the defective interface from reflected reflection, so as to achieve the purpose of detecting defects. 4, ultrasonic energy is power than sonic. 5, the ultrasonic loss is very small in solid transmission , probe depth, as occurs in the hetero - interface by ultrasonic phenomena such as reflection, refraction, especially not by gas - solid interface. If the metal air holes, flaws and layer defects such as defects in a gas or a mixture, when defects at the interface of ultrasonic propagation to the metal and on all or part of the reflection. Reflected ultrasonic probe received, handled through circuits inside the instrument, on the screen of the instrument will show a different height and have a certain pitch waveform.Based on waveform characteristics of determine defect depth, location, and shape of the workpiece.Non - destructive testing is not damaged parts or raw materials subject to the status of the work, a means of detection of surface and internal quality checks, Nondestructive Testing abbreviations short for NDT. Ultrasonic testing is also called ultrasonic, ultrasonic flaw detector, is a type of non - destructive testing. UT is on industrial ultrasonic testing non - destructive testing methods. Ultrasonic enters objects when a defect is encountered, some sound waves produce reflection, transmit and receive an analysis of the reflected wave, exception can accurately gauge the flaws. And is able to display the location and size of internal defects, determination of material thickness.Advantages of ultrasonic inspection is to detect thickness, high sensitivity, high speed, low cost, is harmless to human body, can be positioned and quantitative defects.Display of ultrasonic detection on defects are not intuitive, testing of technical difficulty, vulnerable to subjective and objective factors, and inspection results are not easy to hold, ultrasonic testing requirements on the work surface smooth, requiring experienced inspectors to identify defects types, suitable for the part of considerable thickness inspection, ultrasonic inspection has its limitations.Variety of ultrasonic flaw detector, but most widely application of pulse - echo ultrasonic flaw detector. In general, in uniform material, presence of defect will create material discontinuity,this often acoustic impedance of the discontinuity is inconsistent , by the reflection theorem we know that, in two different acoustic impedance by ultrasonic reflection on the interface of media occurs. Size and interface on both sides of the reflected energy media differences in acoustic impedance and orientation, relative to the size of the interface. Pulse - echo ultrasonic flaw detector is designed according to this principle. Most of pulse - echo ultrasonic flaw detector is a scan, the so-called A-scan display is the way the display of ultrasonic detection in materials is the horizontal coordinate of transmission time or distance, the ordinate is the amplitude of ultrasonic reflected wave. Such as , in a workpiece in the exists a defects , because defects of exists , between defects and material formed a different media junction surface, interface of sound impedance different , when launch of ultrasonic encountered this interface will occurs reflection , reflection back of energy and probe received it, in monitor screen in the horizontal of must of location on will display out a reflection wave of waveform , horizontal of this location is defects wave in was detection material in the of depth . The reflected wave height and shape of different because of different defects, reflecting the nature of the defectNow is usually on the measured object, human launch industrial materials such as ultrasound, and then use its reflection, Doppler effect, transmission to get the formation of internal information and processing of measured object image. Ultrasonic flaw detector which more general Doppler effect method is using ultrasonic in encountered movement of object Shi occurs of more general Doppler frequency moved effect to came the object of movement direction and speed , characteristics ; transmission rule is by analysis ultrasonic penetrating had was measuring object of changes and came object of internal characteristics of , its application currently also is development stage ; ultrasonic flaw detector here main describes of is currently application up to of by reflection method to gets object internal characteristics information of method. Reflection method is based on ultrasonic in by different sound impedance organization interface will occurs strong reflection of principle work of , as we all know , When sonic from a media spread to another media in the interface will occurs reflection , and media of differences more large reflection will more large , so we can launch out penetrating force strong , and to line spread of ultrasonic to a object , and on reflection back of ultrasonic for received and under these reflection back of ultrasonic , and range , situation on can judgment out this organization in the contains of various media of size , and distribution situation and various media of comparison differences degree , information which reflection back of ultrasonic of has can reflect out reflection interface away fromdetection surface of distance , range can reflect out media of size , and comparison differences degree , characteristics , ultrasonic flaw detector to judgment out the was measuring object is has exception . In this process involves many aspects of content, including produce, receive, ultrasonic signal conversion and processing. One method is through the circuit of ultrasonic excitation signals to crystals such as quartz, lithium sulfate, with the piezoelectric effect, making it resulting in ultrasonic vibration ; receives the reflected ultrasonic waves when the piezoelectric crystals, there will be pressure from the reflected sound waves and electrical signals and transferred to the signal processing circuit for a series of processing, observation of ultrasonic flaw detector resulting images for people to judge.Types of image processing can be divided into A type display display, M and B type show, C-type display, such as F-type display. Which A type display is will received to of ultrasonic signal processing into waveform image , under waveform of shape can see was measuring object inside is has exception and defects in there , and has more large , ultrasonic flaw detector main for industrial detection ; M type display is will a section after fai of processing of detection information by time order expand formation a dimension of " space more points movement timing figure " , for observation internal is movement state of object , ultrasonic flaw detector as movement of organ , and artery vascular; B type display is will side - by - side many section after fai of processing of detection information group synthesis of second dimension of , and reflect out was measuring object internal fault section of " Anatomy image " hospital in using of B Super is with this principle do out of , ultrasonic flaw detector for observation internal is static of object ; and c type display , and F type display now with was comparison less . Detection of ultrasonic flaw detector can be very accurate, and more convenient, fast compared to other testing methods, nor harmful to detect objects and actions, so welcomed by the people more and more popular, has a very broad prospects for development. With the further development of electronic technology and software technology, digital ultrasonic flaw detector there are broad development prospects. Believe in the near future, more advanced new generation of digital intelligent ultrasonic flaw detector will gradually replace traditional analog detector, mainly for image display detector will be widely used in industrial inspection.Ultrasonic characterization of defects is always a difficult problem, still mainly relies on experience and analysis of inspection personnel, and poor accuracy. Development of the modern discipline of artificial intelligence for the realization of instrument automatic defect characterization offers the potential. Application of pattern recognition technology and expert systems, various characteristics of a large number of known defects input sample library, to accept the equipment people experience, and after studying with automatic defect characterization capabilities.超声波简介及其应用超声波是频率高于20千赫的机械波。