机械毕业英语论文翻译5000字-车床
车床描述的英语作文
车床描述的英语作文In the world of machining and precision engineering, the lathe stands tall as a testament to human ingenuity and craftsmanship. This versatile tool has been a staple of workshops and factories for centuries, and its impact on the industrial revolution cannot be overstated. The lathe is not just a machine; it's an artist's canvas, asculptor's block of marble, and a mechanic's toolbox, all rolled into one.The lathe's design is both elegant and efficient. Its basic structure consists of a bed, which supports the workpiece, a headstock that holds the spindle and drives the workpiece, and a tailstock that supports the workpiece from the other end. The spindle, driven by a motor, rotates the workpiece, while the cutting tool, held by a toolpost, is fed manually or automatically against the workpiece to shape it.The beauty of the lathe lies in its adaptability. Whether it's turning a metal rod into a precision shaft, shaping a wooden block into a delicate sculpture, ormilling a complex part for a machine, the lathe can handleit with ease. This versatility is made possible by the wide range of cutting tools and attachments that can be used with it, each designed for a specific task.But the true magic of the lathe lies in the skilled hands of the operator. A skilled machinist can read a blueprint, understand the intricacies of the design, and then translate that vision into reality using the lathe. The precision with which they control the cutting tool, the care with which they select the right tool for the job, and the attention to detail they exhibit throughout the process are what truly set the lathe apart.In today's world of automation and robotics, the role of the lathe might seem outdated. However, the truth isthat no machine can replicate the finesse and precisionthat a skilled machinist can achieve using a lathe. The lathe, with its combination of old-world craftsmanship and modern technology, remains an essential tool for any serious engineer or machinist.From its humble beginnings as a simple wood-turning device, the lathe has come a long way. Today, it's a highly specialized machine, capable of producing parts withtolerances that are measured in microns. Its impact on various industries, from automotive to aerospace, is immeasurable. And with the advent of new materials and technologies, the lathe's future looks even more promising. In conclusion, the lathe is not just a machine; it's a symbol of human ingenuity and craftsmanship. Its precision, adaptability, and the skill required to operate it make it a cherished tool for engineers and machinists alike. As we move into the future, the lathe will continue to play a crucial role in the world of machining and precision engineering, and it will undoubtedly inspire generations of craftsmen to push the boundaries of what's possible.**车床的精密:工匠的最佳拍档**在机械加工和精密工程领域,车床以其卓越的性能证明了人类的智慧与匠心。
机械毕业英语论文翻译5000字车床
英文原文1 LathesLathes are machine tools designed primarily to do turning, facing and boring, Very little turning is done on other types of machine tools, and none can do it with equal facility. Because lathes also can do drilling and reaming, their versatility permits several operations to be done with a single setup of the work piece. Consequently, more lathes of various types are used in manufacturing than any other machine tool.The essential components of a lathe are the bed, headstock assembly, tailstock assembly, and the leads crew and feed rod.The bed is the backbone of a lathe. It usually is made of well normalized or aged gray or nodular cast iron and provides s heavy, rigid frame on which all the other basic components are mounted. Two sets of parallel, longitudinal ways, inner and outer, are contained on the bed, usually on the upper side. Some makers use an inverted V-shape for all four ways, whereas others utilize one inverted V and one flat way in one or both sets, They are precision-machined to assure accuracy of alignment. On most modern lathes the way are surface-hardened to resist wear and abrasion, but precaution should be taken in operating a lathe to assure that the ways are not damaged. Any inaccuracy in them usually means that the accuracy of the entire lathe is destroyed.The headstock is mounted in a foxed position on the inner ways, usually at the left end of the bed. It provides a powered means of rotating the word at various speeds . Essentially, it consists of a hollow spindle, mounted in accurate bearings, and a set of transmission gears-similar to a truck transmission—through which the spindle can be rotated at a number of speeds. Most lathes provide from 8 to 18 speeds, usually in a geometric ratio, and on modern lathes all the speeds can be obtained merely by moving from two to four levers. An increasing trend is to provide a continuously variable speed range through electrical or mechanical drives.Because the accuracy of a lathe is greatly dependent on the spindle, it is of heavy construction and mounted in heavy bearings, usually preloaded tapered roller or ball types. The spindle has a hole extending through its length, through which long bar stock can be fed. The size of maximum size of bar stock that can be machined when the material must be fed through spindle.The tailsticd assembly consists, essentially, of three parts. A lower casting fits on the inner ways of the bed and can slide longitudinally thereon, with a means for clamping the entire assembly in any desired location, An upper casting fits on the lower one and can be moved transversely upon it, on some type of keyed ways, to permit aligning the assembly is the tailstock quill. This is a hollow steel cylinder, usually about 51 to 76mm(2to 3 inches) in diameter, that can be moved several inches longitudinally in and out of the upper casting by means of a hand wheel and screw.The size of a lathe is designated by two dimensions. The first is known as the swing. This is the maximum diameter of work that can be rotated on a lathe. It is approximately twice the distance between the line connecting the lathe centers and the nearest point on the ways, The second size dimension is the maximum distancebetween centers. The swing thus indicates the maximum work piece diameter that can be turned in the lathe, while the distance between centers indicates the maximum length of work piece that can be mounted between centers.Engine lathes are the type most frequently used in manufacturing. They are heavy-duty machine tools with all the components described previously and have power drive for all tool movements except on the compound rest. They commonly range in size from 305 to 610 mm(12 to 24 inches)swing and from 610 to 1219 mm(24 to 48 inches) center distances, but swings up to 1270 mm(50 inches) and center distances up to 3658mm(12 feet) are not uncommon. Most have chip pans and a built-in coolant circulating system. Smaller engine lathes-with swings usually not over 330 mm (13 inches ) –also are available in bench type, designed for the bed to be mounted on a bench on a bench or cabinet.Although engine lathes are versatile and very useful, because of the time required for changing and setting tools and for making measurements on the work piece, thy are not suitable for quantity production. Often the actual chip-production tine is less than 30% of the total cycle time. In addition, a skilled machinist is required for all the operations, and such persons are costly and often in short supply. However, much of the operator’s time is co nsumed by simple, repetitious adjustments and in watching chips being made. Consequently, to reduce or eliminate the amount of skilled labor that is required, turret lathes, screw machines, and other types of semiautomatic and automatic lathes have been highly developed and are widely used in manufacturing.2 Numerical ControlOne of the most fundamental concepts in the area of advanced manufacturing technologies is numerical control (NC). Prior to the advent of NC, all machine tools ere manually operated and controlled. Among the many limitations associated with manual control machine tools, perhaps none is more prominent than the limitation of operator skills. With manual control, the quality of the product is directly related to and limited to the skills of the operator. Numerical control represents the first major step away from human control of machine tools.Numerical control means the control of machine tools and other manufacturing systems through the use of prerecorded, written symbolic instructions. Rather than operating a machine tool, an NC technician writes a program that issues operational instructions to the machine tool. For a machine tool to be numerically controlled, it must be interfaced with a device for accepting and decoding the programmed instructions, known as a reader.Numerical control was developed to overcome the limitation of human operators, and it has done so. Numerical control machines are more accurate than manually operated machines, they can produce parts more uniformly, they are faster, and the long-run tooling costs are lower. The development of NC led to the development of several other innovations in manufacturing technology:Electrical discharge machining,Laser cutting,Electron beam welding.Numerical control has also made machine tools more versatile than their manually operated predecessors. An NC machine tool can automatically produce a wide of parts,each involving an assortment of widely varied and complex machining processes. Numerical control has allowed manufacturers to undertake the production of products that would not have been feasible from an economic perspective using manually controlled machine tolls and processes.Like so many advanced technologies, NC was born in the laboratories of the Massachusetts Institute of Technology. The concept of NC was developed in the early 1950s with funding provided by the U.S. Air Force. In its earliest stages, NC machines were able to made straight cuts efficiently and effectively.However, curved paths were a problem because the machine tool had to be programmed to undertake a series of horizontal and vertical steps to produce a curve. The shorter the straight lines making up the steps, the smoother is the curve, Each line segment in the steps had to be calculated.This problem led to the development in 1959 of the Automatically Programmed Tools (APT) language. This is a special programming language for NC that uses statements similar to English language to define the part geometry, describe the cutting tool configuration, and specify the necessary motions. The development of the APT language was a major step forward in the fur ther development from those used today. The machines had hardwired logic circuits. The instructional programs were written on punched paper, which was later to be replaced by magnetic plastic tape. A tape reader was used to interpret the instructions written on the tape for the machine. Together, all of this represented a giant step forward in the control of machine tools. However, there were a number of problems with NC at this point in its development.A major problem was the fragility of the punched paper tape medium. It was common for the paper tape containing the programmed instructions to break or tear during a machining process. This problem was exacerbated by the fact that each successive time a part was produced on a machine tool, the paper tape carrying the programmed instructions had to be rerun through the reader. If it was necessary to produce 100 copies of a given part, it was also necessary to run the paper tape through the reader 100 separate tines. Fragile paper tapes simply could not withstand the rigors of a shop floor environment and this kind of repeated use.This led to the development of a special magnetic plastic tape. Whereas the paper carried the programmed instructions as a series of holes punched in the tape, the plastic tape carried the instructions as a series of magnetic dots. The plastic tape was much stronger than the paper tape, which solved the problem of frequent tearing and breakage. However, it still left two other problems.The most important of these was that it was difficult or impossible to change the instructions entered on the tape. To made even the most minor adjustments in a program of instructions, it was necessary to interrupt machining operations and make a new tape. It was also still necessary to run the tape through the reader as many times as there were parts to be produced. Fortunately, computer technology became a reality and soon solved the problems of NC associated with punched paper and plastic tape.The development of a concept known as direct numerical control (DNC) solved the paper and plastic tape problems associated with numerical control by simply eliminating tape as the medium for carrying the programmed instructions. In directnumerical control, machine tools are tied, via a data transmission link, to a host computer. Programs for operating the machine tools are stored in the host computer and fed to the machine tool an needed via the data transmission linkage. Direct numerical control represented a major step forward over punched tape and plastic tape. However, it is subject to the same limitations as all technologies that depend on a host computer. When the host computer goes down, the machine tools also experience downtime. This problem led to the development of computer numerical control.3 TurningThe 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 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, 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 turrets 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 screw machine. Quantities less 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 on material turned, tooling , and feeds and speeds employed, minimum tolerances that can be held on automatic tracer lathes are not necessarily the most economical tolerances.In some cases, tolerances of are held in continuous production using but one cut . groove width can be held to on some parts. Bores and single-point finishes can be held to . On high-production runs where maximum output is desirable, a minimum tolerance of is economical on both diameter and length of turn.中文译文车床主要是为了进行车外圆、车端面和镗孔等项工作而设计的机床。
【机械类文献翻译】关于数控车床
英文原文On the NC latheCNC machine tool numerical control machine tools (Computer numerical control machine tools) abbreviation, is provided with a program control system of automatic machine tools. The logic control system can deal with the control code or other symbolic instruction specified program, and decoding the digital code, said information carrier, through the numerical control device input. After processing by CNC device control signals, control the machine movements, by drawing the shape and size requirements, will be automatically processed by the parts.Features: CNC machine tool operation and monitoring of all completed in the numerical control unit, it is the brain of CNC machine tools. Compared with the general machine tools, CNC machine tools has the following characteristics:● the processing object adaptability, adapt to the characteristics of mold products such as a single production, provide the appropriate processing method for die and mould manufacturing;● high machining accuracy, proce ssing with stable quality;● can coordinate linkage, processing complex shape parts;● machining parts change, only need to change the program, can save the preparation time of production;● the machine itself high precision, rigidity, can choose the amoun t of processing good, high productivity (3~5 times as common machine);The machine is a high degree of automation, reducing labor intensity;● conducive to the production management modernization. The use of CNC machine tools and the standard code of digital information processing, information transmission, the use of computer control method, has laid the foundation for the integration of computer aided design, manufacturing and management;● on the operators of higher quality, higher demands for the repair of the technical staff;● high reliability.Composition: CNC machine tools in general by the input medium, man-machine interactive equipment, CNC equipment, feed servo drive system, spindle servo drive system, the auxiliary control device, feedback apparatus and adaptive control device etc.. [4] in NC machining, NC milling processing is the most complex, need to solve most problems. NC programming of NC line in addition to CNC milling, cutting, CNC EDM, CNC lathe, CNC grinding, each with its owncharacteristics, servo system is the role of the motion signal is converted into the machine moving parts from the numerical control device of pulse. Concrete has the following parts: the structure of CNC machine tools.Driver: he is driving parts of CNC machine tools, actuator, including spindle drive unit, feeding unit, spindle motor and feed motor. He through the electric or electro-hydraulic servo system to realize the spindle and feed drive under the control of numerical control device. When several feed linkage, can complete the positioning, processing line, plane curve and space curve.The main performance(1) the main dimensions.(2) the spindle system.(3) feed system.(4) tool system.(5) electrical. Including the main motor, servo motor specifications and power etc..(6) cooling system. Including the cooling capacity, cooling pump output.(7) dimensions. Expressed as length * width * height.Development trend of CNC lathe:High speed, precision, complex, intelligent and green is the general trend in the development of CNC machine tool technology, in recent years, made gratifying achievements in practicality and industrialization. Mainly in the:1 machine tool composite technology to further expand with the CNC machine tool technology, composite processing technology matures, including milling - car compound, car milling compound, car - boring - drill - gear cutting compound, composite grinding, forming, composite processing, precision and efficiency of machining is greatly improved. "One machine is a processing factory", "one card, complete processing" concept is being accepted by more people, the development of compound processing machine tool is the trend of diversified.Intelligent technology 2 CNC machine tools have a new breakthrough, in the performance of NC system has been reflected more. Such as: automatically adjust the interference anti-collision function, after the power of workpiece automatically exit safety power-off protection function, machining parts detection and automatic compensation function of learning, high precision machining parts intelligent parameter selection function, process automatic elimination of machine vibration functions into the practical stage, intelligent upgrade the function of machine and quality.The 3 robots enable flexible combination of flexible combination of higher efficiency of robot and the host are widely used, make flexible line more flexible, extending the function, flexible line shorten further, more efficient. Robot and machining center, milling composite machine, grinder, gear processing machine tool, tool grinding machine, electric machine, sawing machine, punching machine, laser cutting machine, water cutting machine etc. various forms of flexible unit and flexible production line has already begun the application.4 precision machining technology has the machining precision of CNC metal cutting machine tools from the yarn in the original (0.01mm) up to micron level (0.001mm), some varieties has reached about 0.05 μ M. Micro cutting and grinding machining of ul tra precision CNC machine tools, precision can reach about 0.05 μ m, shape precision can reach about 0.01 μ M. Special processing precision by using optical, electrical, chemical, energy can reach nanometer level (0.001 μ m). By optimizing the design of ma chine tool structure, machine tool parts of ultra precision machining and precision assembly, using high precision closed loop control and temperature, vibration and other dynamic error compensation technology, improve the geometric accuracy of machine tool processing, reduce the shape of error, surface roughness, and into the submicron, nano super finishing tiThe 5 functional component to improve the performance of functional components are at a high speed, high precision, high power and intelligent direction, and obtain the mature application. A full digital AC servo motor and drive device, high technology content of the electric spindle, linear motor, torque motor, linear motion components with high performance, application of high precision spindle unit and other function parts, greatly improving the technical level of CNC machine tools.The feed drive system of CNC lathe:Effect of feed drive system,The feed drive system of CNC machine tools will be received pulse command issued by the numerical control system, and the amplification and conversion machine movements carry the expected movement.Two, the feeding transmission system requirementsIn order to guarantee the machining accuracy of NC machine tool is high, the feed drive system of transmission accuracy, sensitivity high (fast response), stable work, high stiffness and friction and inertia small, service life, and can remove the transmission gap.Category three, feed drive system1, stepping motor servo systemGenerally used for NC machine tools.2, DC servo motor servo systemPower is stable, but because of the brush, the wear resulting in use need to change. Generally used for middle-grade CNC machine tools.3, AC servo motor servo systemThe application is extremely widespread, mainly used in high-end CNC machine tools.4, the linear motor servo systemNo intermediate transmission chain, high precision, the feed speed, no length limit; but the poor heat dissipation, protection requirements are particularly high, mainly used for high-speed machine.Driving component four, feed system1, the ball screw nut pairNC machining, the rotary motion into linear motion, so the use of screw nut transmission mechanism. NC machine tools are commonly used on the ball screw, as shown in Figure 1-25, it can be a sliding friction into rolling friction, meet the basic requirements of the feed system to reduce friction. The transmission side of high efficiency, small friction, and can eliminate the gap, no reverse air travel; but the manufacturing cost is high, can not lock, size is not too big, generally used for linear feed in small CNC machine tool.2, rotary tableIn order to expand the scope of the process of NC machine tools, CNC machine tools in addition to make linear feed along the X, Y, Z three coordinate axes, often also need a circumferential feed movement around Y or Z axis. Circular feed motion of CNC machine tools in general by the rotary table to realize, for machining center, rotary table has become an indispensable part of.Rotary table of commonly used CNC machine tools in the indexing table and NC rotary table.(1) indexing tableIndexing table can only finish dividing movement, not circular feed, it is in accordance with the instructions in the NC system, when indexing will work together with the workpiece rotation angle. When indexing can also use manual indexing. Provisions of indexing table is generally only rotary angle (such as 90, 60 and 45 degree).(2) NC rotary tableNC rotary table appearance similar to the indexing table, but the internal structure and function is not the same. The main function of the NC rotary table is based on the numerical control devicesends command pulse signal, complete circumferential feed movement, various arc processing and surface processing, it can also be graduation work.3, guideRail is an important part of feed drive system, is one of the basic elements of the structure of machine tool, rigidity, precision and accuracy of NC machine tool which determines to a large extent retention. At present, guide the NC machine tool are sliding rail, rolling guideway and hydrostatic guideway.(1) sliding guideSliding guide rail has the advantages of simple structure, easy manufacture, good stiffness, vibration resistance and high performance, widely used in CNC machine tools, the use of most metal plastic form, known as the plastic guide rail, as shown in figure 1-26.On characteristics of the plastic sliding guide: friction characteristic is good, good wear resistance, stable movement, good manufacturability, low speed.(2) rolling guideRolling guide is placed in the rail surface between the ball, roller or needle roller, roller, the rolling friction instead of sliding surface of the guide rail between wipe.Rolling guide rail and the sliding rail, high sensitivity, small friction coefficient, and the dynamic, static friction coefficient is very small, so the motion is uniform, especially in the low speed movement, the stick-slip phenomenon is not easy to occur; high positioning accuracy, repeatability positioning accuracy is up to 0.2 μ m; traction force is small, wear small, portable in movement; good precision, long service life. But the vibration of rolling guide, high requirements on protection, complicated structure, difficult manufacture, high cost.Automatic tool changer:One, the function of automatic tool changerAutomatic tool changing device can help save the auxiliary time of CNC machine tools, and meet in an installation completed procedure, step processing requirements.Two, on the requirement of automatic tool changerNumerical control machine tool for automatic tool changer requirement is: tool change quickly, time is short, high repetitive positioning accuracy, tool storage capacity is sufficient, small occupation space, stable and reliable work.Three, change the knife form1, rotary cutter replacementIts structure is similar to the ordinary lathe turret saddle, according to the processing of different objects can be designed into square or six angle form, consists of the NC system sends out the instruction to the rotary cutter.2, the replacement of the spindle head tool changeThe spindle head pre-loaded required tools, in order to machining position, the main motor is switched on, drives the cutter to rotate. The advantage of this method is that eliminates the need for automatic clamping, cutting tool, clamping and cutting tool moving and a series of complex operation, reduce tool change time, improveThe ATC reliability.3, the use of changing toolThe processing required tools are respectively arranged in the standard tool, adjust the size of the machine after certain way add to the knife, the exchange device from the knife and the spindle take knife switch.Four, the tool switching deviceAutomatic tool change device, device for knife library and the main shaft transmission and handling tool for tool exchange device. Tool exchange often have two kinds: mechanical hand tool exchange and by relative motion of knife and machine tool spindle exchange tool (knife to spindle forThe knife or the spindle motion to the knife knife tool change position), the mechanical hand tool change is most common.Five, the knifeThe knife is one of the most important parts in automatic tool changer, have great influence on the overall design of NC machine tool and its capacity, layout and structure.1, the capacity of the tool storageA number of knife inventory cutters, generally depending on the processing requirements. The capacity of small knife, can not meet the processing needs; capacity is too large, will make the knife database size, covers an area of large, tool selection process for a long time, and the knife library utilization rate is low, the structure is too complex, causing great waste. 2, the knife typeGenerally, the chain disc and drum type knife several.Disc cutter tool was circular arrangement, low utilization of space, size is not large but simple structure.Chain magazine compact structure, large capacity, link shape can also be random bed made of various forms and flexible layout, but also will change the cutter location prominent for tool change, widely used.Drum type or lattice type knife, covers an area of small, compact structure, large capacity, but cutter selection, tool movements are complicated, for centralized knife system for FMS.3, tool selectionOften order tool selection and random selection tool two.The order of tool selection is before processing, the processing required tools to process sequence of insert knife knife, order not wrong, processing adjust knife in order. The work piece changes, the need to reset the tool sequence, the operation is simple, and the processing tool with a workpiece can not be repeated use.A knife is the cutting tool has its own code, optional and can be repeatedly used in processing, also do not put in the fixed knife, knife, the knife is convenient.Technology file is the guiding file workers during processing, process scheme is reasonable, not only affect the efficiency of NC machining, and will directly affect the machining quality. Therefore, before NC programming, NC machining process follows the process of certain principles and combined with the characteristics of CNC lathe seriously and develop in detail the good parts.In the CNC lathe processing parts, should according to the principle of dividing process concentrated, in a fixture as far as possible to complete the most or even all of the surface processing. Part positioning, according to the structure of different shapes, usually cylindrical, face or end clamping, and strive to design basis, process reference and programming the unification datum.The main contents are: analysis of NC machining technology of part drawings, clear processing content; determination method, workpiece on lathe the surface processing sequence and tool feed line and cutting tools, fixtures and cutting the amount of choice.Analysis, part drawing processIn the machining process planning of parts, first of all to carry on in-depth analysis to the processing object. For NC turning process should consider the following aspects:1 reading part drawing, analysis of geometric conditions of part contourIn turning process of manual programming, to calculate each node coordinates; in automatic programming, to define the components outline all geometric elements. Therefore, in the analysis of parts should pay attention to:Parts of the map is missing a dimension, the geometric conditions are not sufficient to constitute the part outline, influence;Map location map parts of the ambiguity or dimension is not clear, so that the program can't start;The part drawing geometry given is not reasonable, resulting in mathematical difficulties.The part drawing dimensioning methods should adapt to the characteristics of CNC lathe processing, should size or directly given coordinate dimension with the same standard.2 dimensional accuracy requirementsAnalysis of the pattern of parts size precision requirements, to determine whether achieve the turning process, and determine the process method to control the dimension precision.In the analysis process, but also can convert some dimensions such as size, incremental and absolute size and dimension chain calculation. In the use of NC lathe turning parts, average value of components often required size and maximum and minimum limit of size size as the basis of programming.3 shape and position accuracy requirementsPattern of parts tolerance of shape and location given is important foundation to ensure the parts precision. When machining parts, to determine the location reference and measurement reference according to the requirements, can also carry out some technical processing according to the special needs of CNC lathe parts, in order to control effectively the shape and position accuracy.4 requirements of surface roughnessSurface roughness is an important requirement of micro precision parts of the surface, but also the reasonable selection of NC lathe, cutting tools and cutting the amount determined on the basis of.5 material and heat treatment requirementsThe part drawing on material and heat treatment given requirements, is the choice of cutter, CNC lathe, cutting the amount determined on the basis of model.Determination of two and fixture, clamping scheme selectionDivision 1.(1) according to the tool used by the process division can improve machining efficiency.(2) can keep the NC lathe machining according to the rough, finishing process division adopted this approach accuracy.The 2 part is determined and the fixture clamping scheme selectionThe CNC lathe parts mounting method is the same with the ordinary lathe, universal fixture should try to choose the existing clamping, and attention should be paid to reduce clamping times, as far as possible in one clamping parts can put all to processing surface processing. Datum location should be coincident with the design reference, in order to reduce the positioning error effect on the dimensional accuracy.CNC lathe with chuck with three jaws to clamp workpiece; shaft parts can also be used to support the tailstock center. Due to the NC lathe spindle speed is very high, for the convenience of the workpiece clamping, the use of hydraulic high-speed power chuck, because it is in the production plant has passed the strict balanced, with a high speed (the speed limit is 4000 ~ 6000rpm), high clamping force (the maximum force is 2000 ~ 8000N), high precision, convenient adjusting claw, a through hole long service life, etc.. By adjusting the pressure of oil cylinder, which can change the clamping force, the special needs of holding various thin-walled workpiece deformation and easy to meet.Deformation of slender shaft processing to reduce stress, improve the machining accuracy, as well as in processing the shaft with hole workpiece inner hole, the hydraulic automatic centering central frame, the centering precision can reach 0.03 mm.Three, determine the processing order and feed routeDetermination of 1 processing sequenceIn the process of NC machine tool, as the processing object is complicated, especially the shape and position of the myriads of changes curve, with the influence of different materials, different from that of the bulk and other factors, in the formulation of the processing sequence of specific parts, should make a concrete analysis and distinction, flexible processing. Only in this way, can the processing order of the rational, so as to achieve excellent quality, high efficiency and low cost objective.(1) the coarse to fineIn order to improve production efficiency and ensure the precision parts processing quality, in the cutting process, should arrange the roughing process, in a relatively short period of time, the finishing before machining allowance amount of removed, at the same time as much as possible to meet the precision machining allowance uniformity requirements.When the roughing process arrangement is finished, and then arrange the semi-finish machining and finish machining for the knife after the. Among them, arrange the semi-finishing aims, when after the rough machining allowance of uniformity can not meet the precision requirement, canarrange the semi-finish machining as a transitional process, in order to make the finishing allowance is small and uniform.In the arrangement of a knife or blade finish machining process of the part, the final contour should be the last knife and continuous processing. At this time, the cutting tool and cutter location to consider appropriate, try not to arrange the cut and cut out or tool change and pause in a continuous contour, so as to avoid sudden changes of cutting force caused by elastic deformation, resulting in smooth connection defects, surface scratch shape mutation or retention tool mark profile.(2) to nearly far after processing, reduce air travel timeHere said the far and near, is according to the processing site relative to the size of the knife point distance. In general, especially in the rough, usually arranged from near the site of the first processing tool, tool bit far from site after processing, in order to shorten tool moving distance, reduce air travel time. For turning, the first after the far past helps maintain the rough orsemi-finished parts of the rigid, improve the cutting condition.(3) and crossOn both the inner surface (inner type cavity), and outer surface of machined parts, the processing sequence arrangement, should be done before and after surface rough machining, inner and outer surface finishing. Must not be parts of a portion of the surface (the inner or outer surface) after machining, processing and other surface (inner or outer surface).(4) surface of first principlesSurface is used as a fine benchmark priority should be processed, because the surface of locating datum is more precise, clamping error is smaller. For example, shaft parts processing, always first machining center hole, and then to the center hole for precision machining surface and surface.The principle is not immutable and frozen, for some special cases, you need to take a flexible scheme.Determination of processing feed line 2The feed line is the tool relative to the workpiece in the whole movement process, it not only includes the steps of content, but also reflect the step sequence. One of the feed line is the basis of programming.Determine the processing route must keep the size precision and surface quality of machining parts, then consider the numerical calculation is simple, knife route as short as possible, higher efficiency. Because of the feed line finishing is basically along the contour sequence, therefore the determination of feed line focus is to determine the feed line rough machining and air travel. The following will analyze:(1) the relationship between processing route and machining allowanceIn the CNC lathe is not to popularize the use of conditions, the general should be a roughcast margin too much, especially with forging, casting hard layer cushion placed in ordinary lathe. If must use NC lathe machining, should pay attention to the flexible program. The first cutting processing must arrange some subroutine to margin too much site.(2) the tool cut, cut outThe processing of CNC machine tools, to arrange the tool cut, cut out the route, the tangent direction to make the tool along the outline of the cut, cut out.(3) to determine the shortest route for emptyDetermine the shortest tool path, in addition to rely on a lot of practical experience, should be good at analysis, if necessary, supplemented by some simple calculations.(4) determine the cutting feed shortestCutting feed route is short, can effectively improve the production efficiency, reduce the tool wear. In the cutting feed route arrangement the rough or semi-finished, it shall also take into account to be rigid and processing parts processing technology requirements, do not care for this and lose that.Four, to determine the cutting parametersCNC programming, the programmer must determine the cutting parameters of each process, and instructions in the form of written procedures. Cutting parameters including spindle speed, depth of cut and feed speed. For the different processing methods, selection of cutting parameters for different needs. Principle of selection of cutting parameters is: to ensure the accuracy and surface roughness of the parts processing, give full play to the tool cutting performance, guarantee a reasonable tool life and give full play to the performance of the machine tool, to maximize the productivity, reduce the cost of.To determine the 1 spindle speed(1) determine the spindle speed of light carSpindle speed should be based on the allowable cutting speed and workpiece diameter selection, the calculation formula is as followsN=1000v/ (d)Type V -- the cutting speed (M / min), determined by the tool life.N -- the spindle speed (R / min);D -- or the diameter of cutter and workpiece diameter (mm).Spindle speed calculation n finally depends on the machine specifications selecting machine or close to the speed of.(2) the car threaded spindle speedIn thread cutting, the lathe spindle speed will be thread pitch (or lead) factors affecting size, driving motor movements frequency characteristics and thread interpolation operation speed, the different NC systems, recommended the spindle speed range of different options. Spindle speed as most ordinary lathe CNC system recommended threading:N ≤ 1200/p-KType P -- pitch or lead the thread (mm);K -- the insurance factor, usually taken as 80;N -- the spindle speed, rpm.To determine the 2 feed speedThe feed velocity is an important parameter in the CNC machine tool cutting, mainly according to the machining accuracy and surface roughness value selection of parts and tool, workpiece material properties. The maximum speed limit by the performance of machine tool stiffness and feed system.To determine the feed speed is the principle:(1) when the workpiece quality requirements can be guaranteed, in order to improve the production efficiency, can choose the higher feed rate. 100 ~ 200mm / min range selection.(2) in cutting, machining deep hole or processing of high-speed steel cutting tool, should choose a lower feeding rate, generally in the 20 ~ 50mm / min range selection.(3) when processing high precision and surface roughness values is small, the feed rate should be smaller, the range of 20~50mm/min selection.(4) the tool to air travel, especially to zero distance, can be set to the highest feed speed setting of the machine tool CNC system.To determine the depth of the 3The cutting depth was decided according to machine tool, workpiece and cutting tool rigidity, stiffness in the permit conditions, should as far as possible back an amount equal to the machining allowance of the workpiece, thus reducing the feeding times, improve production efficiency. In。
本科毕业论文中英文翻译车床精品
本科毕业论文中英文翻译学生姓名:所在院系:机电学院所学专业:机械设计制造及其自动化学习参考车床主要是为了进行车外圆、车端面和镗孔等项工作而设计的机床。
车削很少在其他种类的机床上进行,而且任何一种其他机床都不想车床那样方便地进行车削加工。
由于车床还可以用来钻孔和铰孔,车床的多功能性可以使工件在一次装夹中进行几种加工。
因此,在生产中使用的各种车床比任何种类的机床都多。
普通车床:普通车床作为最早的金属切削机床中的一种,目前仍然有许多有用的和人们所需要的特性。
现在,这些机床主要用在规模较小的工厂中,进行小批量的生产,而不是进行大批量的生产。
普通车床的加工偏差主要取决于操作者的技术熟练程度。
设计工程师应该认真的确定由熟练工人在普通车床上加工的试验零件的公差。
在把试验零件重新设计为生产零件时,应该选用经济的公差。
转塔车床:对生产加工设备来说,目前比过去更着重评价是否具有精确的和快速的重复加工能力。
应用这个标准来评价具体的加工方法,转塔车床可以获得较高的质量评定。
在为小批量的零件(100—200 件)设计加工方法时,采用转塔车床是经济的。
为了在转塔车床上获得极可能小的公差值,设计人员应该尽量将加工工序的数目减至最少。
自动螺丝车床:自动螺丝车床通常被分为以下几种类型:单轴自动、多轴自动和自动夹紧车床。
自动螺丝车床最初是用来对螺钉和类似的带有螺纹的零件进行自动化和快速加工的。
但是。
这种车床的用途早就超过了这个狭窄的范围。
现在,它在许多类型的精密零件的大批量生产中起着重要的作用。
车床的基本部件有:床身、主轴箱部件、尾架部件、溜板部件丝杠和光杠。
床身是车床的基础件。
它通常是由于经过充分正火或时效处理的灰铸铁或者球墨铸铁之城。
它是一个兼顾的刚性框架,所有其他基本部件都安装在车床身上。
通常在床身上有内外讲足平行的导轨。
有些制造厂对全部四条导轨都采用导轨尖学习参考顶朝上的三角形导轨(即山形导轨),而有的制造厂则在一组中或者两组中都采用一个三角形导轨和一个矩形导轨。
机械外文翻译中英文-机床【范本模板】
英文原文Basic Machining Operations and Cutting TechnologyBasic 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 work piece 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 considerably shorter than the workpiece from which it came but with a corresponding increase in thickness of the uncut chip. The geometrical shape of workpiece depends on the shape of the tool and its path during the machining operation。
车床介绍的英文作文
车床介绍的英文作文英文:As a professional machinist, I have extensiveexperience with lathes. Lathes are a type of machine tool used to shape metal or wood by rotating the workpiece against a cutting tool. They are commonly used in manufacturing and repair operations.There are many different types of lathes, including engine lathes, turret lathes, and CNC lathes. Each type has its own unique features and advantages. For example, engine lathes are versatile and can be used for a wide range of tasks, while CNC lathes are highly automated and canproduce complex parts with great precision.One of the most important parts of a lathe is the chuck, which holds the workpiece in place while it is being machined. Chucks can be either manual or automatic, and can be designed to hold a variety of different shapes and sizesof workpieces.Another important component of a lathe is the tool post, which holds the cutting tool and allows it to be moved into position for machining. The tool post can be manually or automatically adjusted, depending on the type of lathe.Overall, lathes are essential tools for any machinistor manufacturer. They allow for precise shaping and machining of metal and wood, and can be used for a wide range of tasks.中文:作为一名专业的机械师,我在车床方面有着丰富的经验。
车床类英语作文
The Evolution and Importance of LatheMachines in Modern ManufacturingIn the world of precision engineering and manufacturing, the lathe machine stands as a timeless icon ofcraftsmanship and technology. Originating in the early Industrial Revolution, the lathe has undergone numerous transformations, evolving from its simple beginnings into a highly sophisticated and versatile tool. Its importance in modern manufacturing cannot be overstated, as it forms the backbone of numerous industries, from automotive to aerospace.The basic principle of a lathe is relatively straightforward. It involves the rotation of a workpiece around a fixed axis while a cutting tool is applied toshape or modify the workpiece's surface. This fundamental concept has been refined and expanded upon over the centuries, leading to an array of specialized lathes designed for specific tasks.Early lathes were manually operated, relying on theskill and expertise of the operator. However, with the advent of automation and computer-assisted machining, thelathe's capabilities have been greatly expanded. Modern lathes are often integrated into Computer Numerical Control (CNC) systems, allowing for highly precise and repeatable operations. This integration has not only increased productivity but has also opened up new possibilities for complex machining tasks.The role of the lathe in modern manufacturing is multifaceted. It is used to produce components for a wide range of industries, from small precision parts for watches and electronics to large components for heavy machinery and aircraft. The precision and accuracy achieved with lathe machining are crucial for ensuring the quality and performance of these products.Moreover, the lathe's adaptability and versatility make it a valuable asset in research and development. It allows engineers to prototype and test new designs quickly and efficiently, facilitating innovation and pushing the boundaries of what is possible.In conclusion, the lathe machine remains a vital component of modern manufacturing. Its evolution from a simple tool of the tradesman to a highly advanced andautomated machining center is a testament to the power of technology and innovation. As we look towards the future of manufacturing, the lathe will continue to play a pivotal role, driving progress and enabling the creation of even more sophisticated and innovative products.**车床类英语作文:车床在现代制造业中的演变与重要性** 在精密工程和制造业的世界中,车床作为工匠精神和技术的永恒象征,具有举足轻重的地位。
机械类车床外文翻译
毕业设计(论文)——外文翻译(原文)Lathe来源:/wiki/LatheA lathe is a machine tool which spins a block of material to perform various operations such as cutting, sanding, knurling, drilling, or deformation with tools that are applied to the workpiece to create an object which has symmetry about an axis of rotation.Lathes are used in woodturning, metalworking, and glassworking. Lathes can be used to shape pottery, the best-known design being the potter's wheel. Most suitably equipped metalworking lathes can also be used to produce most solids of revolution, plane surfaces and screw threads or helices. Ornamental lathes can produce three-dimensional solids of incredible complexity. The material is held in place by either one or two centers, at least one of which can be moved horizontally to accommodate varying material lengths. Examples of objects that can be produced on a lathe include cue sticks, table legs, bowls, baseball bats, crankshafts and camshafts.HistoryThe lathe is an ancient tool, dating at least to the Egyptians ,and known and used in Greece, the Roman and Byzantine Empires.The origin of turning dates to around 1300BC when the Egyptians first developed a two-person lathe. One person would turn the wood workpiece with a rope while the other used a sharp tool to cut shapes in the wood. The Romans improved the Egyptian design with the addition of a turning bow. Early bow lathes were also developed and used in Germany, France and Britain. In the Middle Ages a pedal replaced hand-operated turning, freeing both the craftsman's hands to hold the woodturning tools. The pedal was usually connected to a pole, often a straight-grained sapling. The system today is called the "spring pole" lathe. Spring pole lathes were in common use into the early 20th Century. A two-person lathe, called a "great lathe", allowed a piece to turn continuously (like today's power lathes). A master would cut the wood while an apprentice turned the crank。
车床描述的英语作文
The Essence of Lathe Machines: A Technicaland Cultural PerspectiveLathe machines have been a cornerstone of the manufacturing industry for centuries, embodying the essence of precision engineering and human ingenuity. Theseversatile tools have evolved over time, transforming from simple wooden devices into complex metalworking machinesthat can craft objects with micrometer-level accuracy.Their significance extends beyond mere utility, serving asa symbol of technological advancement and cultural progress. The lathe's history can be traced back to ancient times, when wooden lathes were used to shape wooden objects. These early lathes were relatively basic, relying on hand-powered rotation and basic cutting tools. However, it was the Industrial Revolution that truly transformed the lathe, introducing steam-powered versions and later, electrical models that greatly increased productivity and efficiency.Today, lathe machines are used in a wide range of industries, from automotive manufacturing to precision engineering. They are capable of creating intricate parts and components with remarkable precision, making themcrucial in the production of high-quality goods. Thelathe's versatility is further enhanced by the various attachments and accessories that can be added to expand its capabilities.Technically speaking, a lathe consists of several key components: the headstock, which holds the spindle and rotates the workpiece; the tailstock, which supports the workpiece at the opposite end; and the bed, which provides stability and supports the entire machine. The cutting tool, known as the lathe tool or bit, is mounted on a tool post and moved along the bed to shape the workpiece. Theoperator controls the machine using levers and dials, adjusting the speed, feed rate, and depth of cut to achieve the desired results.The art of operating a lathe machine requires skill and precision. An experienced machinist can sense when the tool is making contact with the workpiece, adjusting the cutting force and speed to prevent damage or errors. This skill is honed through years of practice and experience, making machinists highly valued professionals in the manufacturing industry.Culturally, the lathe machine has become a symbol of human ingenuity and technological prowess. It represents the ability of humans to transform raw materials into useful and beautiful objects, using only their knowledge, skills, and tools. The precision and craftsmanship required to operate a lathe machine are a testament to the human capacity for innovation and excellence.In conclusion, the lathe machine is not just a utilitarian tool; it is a testament to human ingenuity and technological advancement. Its ability to transform raw materials into precision-crafted objects is a remarkable feat of engineering, one that continues to inspire and challenge the minds of machinists and engineers alike. As we look towards the future of manufacturing, the lathe machine remains a vital component of our industrial landscape, a symbol of human progress and innovation.**车床的本质:技术与文化的视角**车床几个世纪以来一直是制造业的基石,它体现了精密工程的精髓和人类的智慧。
关于机械车床的英语作文
关于机械车床的英语作文In the realm of modern manufacturing, mechanical lathes occupy a pivotal position, serving as the backbone of precision machining. These versatile machines have undergone significant evolutionary changes over the centuries, transforming from simple wooden lathes to complex, high-tech devices capable of producing intricate parts with remarkable precision.The history of mechanical lathes dates back to ancient times, when simple lathes were used to shape wooden objects. These primitive devices were operated manually, relying on the skill and expertise of the craftsman. Over time, however, technological advancements led to the developmentof more sophisticated lathes, powered by steam, electricity, and eventually, computers.Today, mechanical lathes are at the forefront of modern manufacturing, playing a crucial role in various industries such as automotive, aerospace, and heavy machinery. These machines are capable of precision machining, allowing manufacturers to produce parts with tight tolerances and complex geometries. The accuracy and repeatability ofmechanical lathes are essential for ensuring the quality and reliability of products.The operation of mechanical lathes involves the use of rotating tools to remove material from a workpiece, gradually shaping it into the desired form. These lathes are highly configurable, allowing operators to adjust various parameters such as speed, feed rate, and tool geometry to achieve the desired machining effects. The use of CNC (Computer Numerical Control) technology has further revolutionized mechanical lathing, enabling operators to program complex machining sequences with precision and efficiency.In addition to their role in production, mechanical lathes are also used for research and development, allowing engineers to prototype and test new designs quickly and cost-effectively. The adaptability and versatility of these machines make them invaluable tools for innovation and creativity.The importance of mechanical lathes in modern manufacturing cannot be overstated. They are the backbone of precision machining, enabling the production of high-quality parts and components that are crucial for the operation and performance of various machines and systems. The continuous evolution and advancement of mechanicallathes are expected to further transform the manufacturing industry, driving innovation and productivity to new heights.**机械车床在现代制造业中的演变与重要性**在现代制造业中,机械车床占据着举足轻重的地位,是精密加工的核心。
车床介绍的英文作文
车床介绍的英文作文英文:As a professional machinist, I have had the opportunity to work with many different types of lathes. One of the most common types of lathes is the engine lathe, which is also known as a center lathe. This type of lathe is usedfor turning, drilling, boring, threading, and facing operations.The engine lathe is typically used for machining cylindrical workpieces, such as shafts, rods, and bushings. It is also used for machining flat surfaces, such as flanges and discs. The lathe is equipped with a chuck that holds the workpiece and rotates it around its axis. The cutting tool is mounted on a tool post that can be moved along the lathe bed to adjust the depth of cut.One of the advantages of the engine lathe is its versatility. It can be used to machine a wide range ofmaterials, including metals, plastics, and wood. It is also capable of producing a variety of shapes and sizes, depending on the tooling and setup.Another type of lathe that I have worked with is the CNC lathe. This type of lathe is controlled by a computer program, which allows for precise and automated machining operations. The CNC lathe is capable of producing complex shapes and contours, and is often used in high-volume production environments.Overall, the lathe is an essential tool in the machining industry. It is used in a variety of applications, from small-scale hobby projects to large-scale industrial production. Whether you are a machinist, engineer, or hobbyist, the lathe is a valuable tool to have in your arsenal.中文:作为一名专业的机械师,我有机会与许多不同类型的车床一起工作。
一篇描述车床与维修的英语作文
Lathe Machines and Their MaintenanceIn the realm of manufacturing and precision engineering, the lathe machine holds a pivotal position. This versatile tooling allows for the shaping and formation of various materials, primarily metals, into desired shapes and sizes. However, for a lathe to perform optimally and ensure consistent output, proper maintenance is paramount.The lathe machine, often referred to as the "workhorse" of the workshop, is composed of several intricate partsthat require regular attention. The spindle, which holdsthe workpiece and rotates it during the cutting process, is a crucial component that must be inspected for wear and tear. Lubrication of the spindle and other moving parts is essential to reduce friction and prevent premature wear.The bed of the lathe, which supports the workpiece and the cutting tools, must also be kept clean and free of debris. Any foreign particles on the bed can cause inaccuracies in the workpiece's dimensions and affect the overall quality of the finished product. Regular cleaning and dusting of the lathe bed are necessary to maintain its precision.The cutting tools, which are responsible for shaping the workpiece, must be sharpened and replaced periodically. Blunt tools can not only slow down the cutting process but can also produce inconsistent results. Therefore, it is important to maintain a sharp inventory of cutting tools and replace them promptly when needed.In addition to these routine maintenance tasks,periodic inspections and adjustments by qualified mechanics are recommended. These inspections ensure that all parts of the lathe are aligned correctly and functioning optimally. Adjustments to the machine's settings can be made to compensate for wear and tear, ensuring accurate and consistent results.Moreover, it is crucial to follow the manufacturer's guidelines and recommendations for maintaining the lathe. These guidelines provide insights into the specific care and attention required for different models and types of lathes. Ignoring these recommendations can lead to premature wear, decreased performance, and even potential safety hazards.In conclusion, the lathe machine is an essential tool for precision engineering and manufacturing. Its optimal performance relies heavily on proper maintenance and care. Regular lubrication, cleaning, tool replacement, and periodic inspections by qualified mechanics are all integral to ensuring that the lathe remains a reliable and efficient workhorse in any workshop. By adhering to these maintenance practices, manufacturers can ensure consistent output, maximize machine lifespan, and minimize downtime due to mechanical issues.**车床与维修**在制造和精密工程领域,车床机器占据着举足轻重的地位。
【机械类文献翻译】车床
附录LathesLathes are machine tools designed primarily to do turning, facing and boring, Very little turning is done on other types of machine tools, and none can do it with equal facility. Because lathes also can do drilling and reaming, their versatility permits several operations to be done with a single setup of the work piece. Consequently, more lathes of various types are used in manufacturing than any other machine tool.The essential components of a lathe are the bed, headstock assembly, tailstock assembly, and the leads crew and feed rod.The bed is the backbone of a lathe. It usually is made of well normalized or aged gray or nodular cast iron and provides s heavy, rigid frame on which all the other basic components are mounted. Two sets of parallel, longitudinal ways, inner and outer, are contained on the bed, usually on the upper side. Some makers use an inverted V-shape for all four ways, whereas others utilize one inverted V and one flat way in one or both sets, They are precision-machined to assure accuracy of alignment. On most modern lathes the way are surface-hardened to resist wear and abrasion, but precaution should be taken in operating a lathe to assure that the ways are not damaged. Any inaccuracy in them usually means that the accuracy of the entire lathe is destroyed.The headstock is mounted in a foxed position on the inner ways, usually at the left end of the bed. It provides a powered means of rotating the word at various speeds . Essentially, it consists of a hollow spindle, mounted in accurate bearings, and a set of transmission gears-similar to a truck transmission—through which the spindle can be rotated at a number of speeds. Most lathes provide from 8 to 18 speeds, usually in a geometric ratio, and on modern lathes all the speeds can be obtained merely by moving from two to four levers. An increasing trend is to provide a continuously variable speed range through electrical or mechanical drives.Because the accuracy of a lathe is greatly dependent on the spindle, it is of heavy construction and mounted in heavy bearings, usually preloaded tapered roller or balltypes. The spindle has a hole extending through its length, through which long bar stock can be fed. The size of maximum size of bar stock that can be machined when the material must be fed through spindle.The tailsticd assembly consists, essentially, of three parts. A lower casting fits on the inner ways of the bed and can slide longitudinally thereon, with a means for clamping the entire assembly in any desired location, An upper casting fits on the lower one and can be moved transversely upon it, on some type of keyed ways, to permit aligning the assembly is the tailstock quill. This is a hollow steel cylinder, usually about 51 to 76mm(2to 3 inches) in diameter, that can be moved several inches longitudinally in and out of the upper casting by means of a hand wheel and screw.The size of a lathe is designated by two dimensions. The first is known as the swing. This is the maximum diameter of work that can be rotated on a lathe. It is approximately twice the distance between the line connecting the lathe centers and the nearest point on the ways, The second size dimension is the maximum distance between centers. The swing thus indicates the maximum work piece diameter that can be turned in the lathe, while the distance between centers indicates the maximum length of work piece that can be mounted between centers.Engine lathes are the type most frequently used in manufacturing. They are heavy-duty machine tools with all the components described previously and have power drive for all tool movements except on the compound rest. They commonly range in size from 305 to 610 mm(12 to 24 inches)swing and from 610 to 1219mm(24 to 48 inches) center distances, but swings up to 1270 mm(50 inches) and center distances up to 3658mm(12 feet) are not uncommon. Most have chip pans and a built-in coolant circulating system. Smaller engine lathes-with swings usually not over 330 mm (13 inches ) –also are available in bench type, designed for the bed to be mounted on a bench on a bench or cabinet.Although engine lathes are versatile and very useful, because of the time required for changing and setting tools and for making measurements on the work piece, thy are not suitable for quantity production. Often the actual chip-production tine is less than 30% of the total cycle time. In addition, a skilled machinist is required for all the operations, and such persons are costly and often in short supply. However, much of the operator’s time is consum ed by simple, repetitious adjustments and inwatching chips being made. Consequently, to reduce or eliminate the amount of skilled labor that is required, turret lathes, screw machines, and other types of semiautomatic and automatic lathes have been highly developed and are widely used in manufacturing.2 Numerical ControlOne of the most fundamental concepts in the area of advanced manufacturing technologies is numerical control (NC). Prior to the advent of NC, all machine tools ere manually operated and controlled. Among the many limitations associated with manual control machine tools, perhaps none is more prominent than the limitation of operator skills. With manual control, the quality of the product is directly related to and limited to the skills of the operator. Numerical control represents the first major step away from human control of machine tools.Numerical control means the control of machine tools and other manufacturing systems through the use of prerecorded, written symbolic instructions. Rather than operating a machine tool, an NC technician writes a program that issues operational instructions to the machine tool. For a machine tool to be numerically controlled, it must be interfaced with a device for accepting and decoding the programmed instructions, known as a reader.Numerical control was developed to overcome the limitation of human operators, and it has done so. Numerical control machines are more accurate than manually operated machines, they can produce parts more uniformly, they are faster, and the long-run tooling costs are lower. The development of NC led to the development of several other innovations in manufacturing technology:Electrical discharge machining,Laser cutting,Electron beam welding.Numerical control has also made machine tools more versatile than their manually operated predecessors. An NC machine tool can automatically produce a wide of parts, each involving an assortment of widely varied and complex machining processes. Numerical control has allowed manufacturers to undertake the production of products that would not have been feasible from an economic perspective using manually controlled machine tolls and processes.Like so many advanced technologies, NC was born in the laboratories of the Massachusetts Institute of Technology. The concept of NC was developed in the early 1950s with funding provided by the U.S. Air Force. In its earliest stages, NC machines were able to made straight cuts efficiently and effectively.However, curved paths were a problem because the machine tool had to be programmed to undertake a series of horizontal and vertical steps to produce a curve. The shorter the straight lines making up the steps, the smoother is the curve, Each line segment in the steps had to be calculated.This problem led to the development in 1959 of the Automatically Programmed Tools (APT) language. This is a special programming language for NC that uses statements similar to English language to define the part geometry, describe the cutting tool configuration, and specify the necessary motions. The development of the APT language was a major step forward in the fur ther development from those used today. The machines had hardwired logic circuits. The instructional programs were written on punched paper, which was later to be replaced by magnetic plastic tape. A tape reader was used to interpret the instructions written on the tape for the machine. Together, all of this represented a giant step forward in the control of machine tools. However, there were a number of problems with NC at this point in its development.A major problem was the fragility of the punched paper tape medium. It was common for the paper tape containing the programmed instructions to break or tear during a machining process. This problem was exacerbated by the fact that each successive time a part was produced on a machine tool, the paper tape carrying the programmed instructions had to be rerun through the reader. If it was necessary to produce 100 copies of a given part, it was also necessary to run the paper tape through the reader 100 separate tines. Fragile paper tapes simply could not withstand the rigors of a shop floor environment and this kind of repeated use.This led to the development of a special magnetic plastic tape. Whereas the paper carried the programmed instructions as a series of holes punched in the tape, the plastic tape carried the instructions as a series of magnetic dots. The plastic tape was much stronger than the paper tape, which solved the problem of frequent tearing and breakage. However, it still left two other problems.The most important of these was that it was difficult or impossible to change the instructions entered on the tape. To made even the most minor adjustments in a program of instructions, it was necessary to interrupt machining operations and make a new tape. It was also still necessary to run the tape through the reader as many times as there were parts to be produced. Fortunately, computer technology became a reality and soon solved the problems of NC associated with punched paper and plastic tape.The development of a concept known as direct numerical control (DNC) solved the paper and plastic tape problems associated with numerical control by simply eliminating tape as the medium for carrying the programmed instructions. In direct numerical control, machine tools are tied, via a data transmission link, to a host computer. Programs for operating the machine tools are stored in the host computer and fed to the machine tool an needed via the data transmission linkage. Direct numerical control represented a major step forward over punched tape and plastic tape. However, it is subject to the same limitations as all technologies that depend on a host computer. When the host computer goes down, the machine tools also experience downtime. This problem led to the development of computer numerical control.3 TurningThe 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 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, 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 turrets 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 screw machine. Quantities less 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 on material turned, tooling , and feeds and speeds employed, minimum tolerances that can be held on automatic tracer lathes are not necessarily the most economical tolerances.In some cases, 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.1.车床车床主要是为了进行车外圆、车端面和镗孔等项工作而设计的机床。
机床的介绍作文英文带翻译
机床的介绍作文英文带翻译英文:As a manufacturing engineer, I have had the opportunity to work with various types of machine tools, including the versatile and essential machine tool known as a lathe. A lathe is a machine tool that rotates a workpiece about an axis of rotation to perform various operations such as cutting, sanding, knurling, drilling, deformation, facing, and turning, with tools that are applied to the workpieceto create an object with symmetry about that axis.The lathe is an incredibly versatile machine tool that can be used to create a wide range of objects, from simple cylindrical shafts and rings to complex engine crankshafts and camshafts. The ability to precisely shape and finish metal, wood, and other materials makes the lathe an indispensable tool in manufacturing and machining processes.One of the key features of a lathe is its ability toperform both symmetrical and asymmetrical turning operations. This means that it can be used to create objects that are perfectly symmetrical, such as a chess piece, as well as objects that have unique and irregular shapes, such as a custom-designed tool handle. The lathe's versatility makes it an essential tool for prototype development and custom part manufacturing.In addition to its versatility, the lathe is also known for its precision and accuracy. By carefully adjusting the speed, feed rate, and cutting tools, a skilled machinist can create objects with incredibly tight tolerances and smooth surface finishes. This level of precision is essential in industries such as aerospace, automotive, and medical device manufacturing, where even the smallest deviation from design specifications can have serious consequences.Overall, the lathe is a crucial machine tool in the world of manufacturing and machining. Its versatility, precision, and ability to create a wide range of objects make it an indispensable tool for engineers, machinists,and manufacturers.中文:作为一名制造工程师,我有机会与各种类型的机床打交道,其中包括一种多功能且必不可少的机床——车床。
关于车床的英文作文
关于车床的英文作文英文:Car lathe, also known as turning machine, is a common machine tool in mechanical processing. It is mainly usedfor turning cylindrical, conical and other rotating surfaces, as well as various types of internal and external threads, grooves and cutting work. As a mechanical engineer, I have had the opportunity to use car lathes in my work.The car lathe is a versatile machine tool. It can be used to process various materials, such as metal, plastic, wood, and even some ceramics. The lathe can also perform a variety of operations, including facing, drilling, boring, turning, and threading. One of the advantages of the car lathe is its ability to produce high-precision parts with tight tolerances. This makes it an essential tool in industries such as aerospace, automotive, and medicaldevice manufacturing.When using a car lathe, it is important to followproper safety procedures. The lathe can be dangerous if not used correctly. For example, if the workpiece is notsecured properly, it can fly off the lathe and cause injury. It is also important to wear appropriate personalprotective equipment, such as safety glasses and gloves.In my work, I have used the car lathe to produce a variety of parts. One example is a shaft for a motor. The shaft needed to be precisely machined to fit into the motor housing and rotate smoothly. Using the car lathe, I wasable to turn the shaft to the required diameter and length, and also add keyways for the motor to engage with. The finished shaft fit perfectly into the motor and functioned as intended.Overall, the car lathe is an essential tool in mechanical engineering. Its versatility and precision makeit a valuable asset in many industries. However, it is important to use the lathe safely and follow proper procedures to avoid injury.中文:车床,也称为车削机,在机械加工中是一种常见的机床。
一篇描述车床与维修的英语作文
Lathe Machines and Their MaintenanceIn the realm of manufacturing and precision engineering, the lathe machine holds a pivotal position. It is aversatile tool that enables the shaping and finishing of various materials, primarily metals, through rotational motion. The precision and accuracy achieved by lathes are crucial for the production of high-quality components and parts. However, to ensure optimal performance and extendits lifespan, regular maintenance and repairs are essential. The lathe machine, with its intricate mechanisms and components, requires a thorough understanding of itsworking principles for effective maintenance. Lubricationis a crucial aspect of maintaining the lathe, as it ensures smooth operation and reduces friction between moving parts. Regular cleaning of the machine, removing dust and debris,is also vital to prevent wear and tear.Moreover, the inspection of lathe parts, such as bearings, gears, and belts, is crucial. Any wear or tear in these parts can significantly affect the machine's performance. Timely replacement of worn-out parts ensuresthe lathe's continuous and efficient operation.Additionally, adjusting the machine's alignment and tensioning belts are essential for maintaining its precision and accuracy.Beyond regular maintenance, unexpected breakdowns and repairs are also a part of lathe ownership. In such cases, it's crucial to have a team of experienced mechanics and engineers on hand to diagnose and rectify the issues quickly. Advanced diagnostic tools and equipment help in pinpointing the exact location of the fault, saving valuable time and resources.In conclusion, the lathe machine is a crucial component of the manufacturing industry, and its proper maintenance and timely repairs are paramount for its efficient and reliable operation. With regular lubrication, cleaning, inspection, and prompt repairs, the lathe can continue to produce high-quality parts, ensuring the smooth running of manufacturing processes.**车床与维修**在制造业和精密工程领域,车床扮演着至关重要的角色。
了解车床英语作文
Understanding the Lathe Machine: An Essential Tool for MetalworkingIn the world of metalworking, the lathe machine stands as a vital piece of equipment, essential for shaping and finishing various metal parts. Originating in the 18th century, the lathe has evolved over time to become a highly specialized and versatile tool, used across various industries, from automotive manufacturing to precision engineering.The basic principle of a lathe is relatively simple. It involves the rotation of a workpiece, usually mounted on a spindle, while a cutting tool is moved against it to remove material and create the desired shape. This basic action can be modified and enhanced through the use of various attachments and accessories, allowing for incredible flexibility and precision.The different types of lathes reflect their diverse applications. Manual lathes, operated by skilled craftsmen, are still used for precision work and small-scale production. However, with the advent of technology, automatic and CNC (Computer Numerical Control) lathes havebecome increasingly popular. These lathes are programmed to perform complex operations with extreme accuracy, greatly enhancing production efficiency and quality.The lathe's role in metalworking cannot be overstated. It is responsible for creating precision parts for engines, machinery, and other complex systems. Without the lathe, many of the modern conveniences we enjoy today, such as cars, computers, and aircraft, would not be possible.However, operating a lathe requires skill and training. The operator must have a deep understanding of themachine's capabilities and limitations, as well as the materials they are working with. Improper operation can lead to inaccuracies, wasted material, and even potential safety hazards.In conclusion, the lathe machine is a fundamental tool of metalworking, essential for creating precision parts across a wide range of industries. Its importance cannot be overstated, and its continued evolution and advancementwill undoubtedly shape the future of metalworking and manufacturing.**了解车床:金属加工的重要工具**在金属加工领域,车床作为一种至关重要的设备,对于塑造和完成各种金属零件起着至关重要的作用。
机床——机械类外文文献翻译、中英文翻译
毕业设计(论文)外文资料翻译系部:专业:姓名:学号:外文出处:English For Electromechanical(用外文写)Engineering附件:1.外文资料翻译译文;2.外文原文。
附件1:外文资料翻译译文机床机床是用于切削金属的机器。
工业上使用的机床要数车床、钻床和铣床最为重要。
其它类型的金属切削机床在金属切削加工方面不及这三种机床应用广泛。
车床通常被称为所有类型机床的始祖。
为了进行车削,当工件旋转经过刀具时,车床用一把单刃刀具切除金属。
用车削可以加工各种圆柱型的工件,如:轴、齿轮坯、皮带轮和丝杠轴。
镗削加工可以用来扩大和精加工定位精度很高的孔。
钻削是由旋转的钻头完成的。
大多数金属的钻削由麻花钻来完成。
用来进行钻削加工的机床称为钻床。
铰孔和攻螺纹也归类为钻削过程。
铰孔是从已经钻好的孔上再切除少量的金属。
攻螺纹是在内孔上加工出螺纹,以使螺钉或螺栓旋进孔内。
铣削由旋转的、多切削刃的铣刀来完成。
铣刀有多种类型和尺寸。
有些铣刀只有两个切削刃,而有些则有多达三十或更多的切削刃。
铣刀根据使用的刀具不同能加工平面、斜面、沟槽、齿轮轮齿和其它外形轮廓。
牛头刨床和龙门刨床用单刃刀具来加工平面。
用牛头刨床进行加工时,刀具在机床上往复运动,而工件朝向刀具自动进给。
在用龙门刨床进行加工时,工件安装在工作台上,工作台往复经过刀具而切除金属。
工作台每完成一个行程刀具自动向工件进给一个小的进给量。
磨削利用磨粒来完成切削工作。
根据加工要求,磨削可分为精密磨削和非精密磨削。
精密磨削用于公差小和非常光洁的表面,非精密磨削用于在精度要求不高的地方切除多余的金属。
车床车床是用来从圆形工件表面切除金属的机床,工件安装在车床的两个顶尖之间,并绕顶尖轴线旋转。
车削工件时,车刀沿着工件的旋转轴线平行移动或与工件的旋转轴线成一斜角移动,将工件表面的金属切除。
车刀的这种位移称为进给。
车刀装夹在刀架上,刀架则固定在溜板上。
溜板是使刀具沿所需方向进行进给的机构。
关于机床的英文作文
关于机床的英文作文英文:As a professional in the manufacturing industry, I have a lot of experience with machine tools. Machine tools, also known as machining centers, are used to shape and form metal and other materials into various shapes and sizes. They are an essential part of many manufacturing processes, including milling, drilling, and turning.One of the most important aspects of machine tools is their precision. They are designed to be incredibly accurate, with tolerances measured in microns. This level of precision is necessary to ensure that the final product meets the required specifications. For example, if a partis being machined for a medical device, it must be precise to ensure that it functions correctly.Another important aspect of machine tools is their versatility. They can be used to produce a wide range ofparts, from small, intricate components to large, complex structures. This versatility is due in part to the wide range of cutting tools that can be used with machine tools. These tools can be changed out quickly and easily, allowing for rapid production of different parts.Of course, like any piece of machinery, machine tools require maintenance and upkeep to ensure that they continue to function properly. This can include regular cleaning and lubrication, as well as more extensive repairs when necessary. It's also important to ensure that the machine tools are being used correctly, as improper use can lead to damage or even injury.Overall, machine tools are an essential part of the manufacturing industry. Without them, it would be impossible to produce many of the products that we rely on every day.中文:作为制造业的专业人士,我对机床有很多经验。
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英文原文1 LathesLathes are machine tools designed primarily to do turning, facing and boring, Very little turning is done on other types of machine tools, and none can do it with equal facility. Because lathes also can do drilling and reaming, their versatility permits several operations to be done with a single setup of the work piece. Consequently, more lathes of various types are used in manufacturing than any other machine tool.The essential components of a lathe are the bed, headstock assembly, tailstock assembly, and the leads crew and feed rod.The bed is the backbone of a lathe. It usually is made of well normalized or aged gray or nodular cast iron and provides s heavy, rigid frame on which all the other basic components are mounted. Two sets of parallel, longitudinal ways, inner and outer, are contained on the bed, usually on the upper side. Some makers use an inverted V-shape for all four ways, whereas others utilize one inverted V and one flat way in one or both sets, They are precision-machined to assure accuracy of alignment. On most modern lathes the way are surface-hardened to resist wear and abrasion, but precaution should be taken in operating a lathe to assure that the ways are not damaged. Any inaccuracy in them usually means that the accuracy of the entire lathe is destroyed.The headstock is mounted in a foxed position on the inner ways, usually at the left end of the bed. It provides a powered means of rotating the word at various speeds . Essentially, it consists of a hollow spindle, mounted in accurate bearings, and a set of transmission gears-similar to a truck transmission—through which the spindle can be rotated at a number of speeds. Most lathes provide from 8 to 18 speeds, usually in a geometric ratio, and on modern lathes all the speeds can be obtained merely by moving from two to four levers. An increasing trend is to provide a continuously variable speed range through electrical or mechanical drives.Because the accuracy of a lathe is greatly dependent on the spindle, it is of heavy construction and mounted in heavy bearings, usually preloaded tapered roller or ball types. The spindle has a hole extending through its length, through which long bar stock can be fed. The size of maximum size of bar stock that can be machined when the material must be fed through spindle.The tailsticd assembly consists, essentially, of three parts. A lower casting fits on the inner ways of the bed and can slide longitudinally thereon, with a means for clamping the entire assembly in any desired location, An upper casting fits on the lower one and can be moved transversely upon it, on some type of keyed ways, to permit aligning the assembly is the tailstock quill. This is a hollow steel cylinder, usually about 51 to 76mm(2to 3 inches) in diameter, that can be moved several inches longitudinally in and out of the upper casting by means of a hand wheel and screw.The size of a lathe is designated by two dimensions. The first is known as the swing. This is the maximum diameter of work that can be rotated on a lathe. It is approximately twice the distance between the line connecting the lathe centers and the nearest point on the ways, The second size dimension is the maximum distancebetween centers. The swing thus indicates the maximum work piece diameter that can be turned in the lathe, while the distance between centers indicates the maximum length of work piece that can be mounted between centers.Engine lathes are the type most frequently used in manufacturing. They are heavy-duty machine tools with all the components described previously and have power drive for all tool movements except on the compound rest. They commonly range in size from 305 to 610 mm(12 to 24 inches)swing and from 610 to 1219 mm(24 to 48 inches) center distances, but swings up to 1270 mm(50 inches) and center distances up to 3658mm(12 feet) are not uncommon. Most have chip pans and a built-in coolant circulating system. Smaller engine lathes-with swings usually not over 330 mm (13 inches ) –also are available in bench type, designed for the bed to be mounted on a bench on a bench or cabinet.Although engine lathes are versatile and very useful, because of the time required for changing and setting tools and for making measurements on the work piece, thy are not suitable for quantity production. Often the actual chip-production tine is less than 30% of the total cycle time. In addition, a skilled machinist is required for all the operations, and such persons are costly and often in short supply. However, much of the operator’s time is co nsumed by simple, repetitious adjustments and in watching chips being made. Consequently, to reduce or eliminate the amount of skilled labor that is required, turret lathes, screw machines, and other types of semiautomatic and automatic lathes have been highly developed and are widely used in manufacturing.2 Numerical ControlOne of the most fundamental concepts in the area of advanced manufacturing technologies is numerical control (NC). Prior to the advent of NC, all machine tools ere manually operated and controlled. Among the many limitations associated with manual control machine tools, perhaps none is more prominent than the limitation of operator skills. With manual control, the quality of the product is directly related to and limited to the skills of the operator. Numerical control represents the first major step away from human control of machine tools.Numerical control means the control of machine tools and other manufacturing systems through the use of prerecorded, written symbolic instructions. Rather than operating a machine tool, an NC technician writes a program that issues operational instructions to the machine tool. For a machine tool to be numerically controlled, it must be interfaced with a device for accepting and decoding the programmed instructions, known as a reader.Numerical control was developed to overcome the limitation of human operators, and it has done so. Numerical control machines are more accurate than manually operated machines, they can produce parts more uniformly, they are faster, and the long-run tooling costs are lower. The development of NC led to the development of several other innovations in manufacturing technology:Electrical discharge machining,Laser cutting,Electron beam welding.Numerical control has also made machine tools more versatile than their manually operated predecessors. An NC machine tool can automatically produce a wide of parts,each involving an assortment of widely varied and complex machining processes. Numerical control has allowed manufacturers to undertake the production of products that would not have been feasible from an economic perspective using manually controlled machine tolls and processes.Like so many advanced technologies, NC was born in the laboratories of the Massachusetts Institute of Technology. The concept of NC was developed in the early 1950s with funding provided by the U.S. Air Force. In its earliest stages, NC machines were able to made straight cuts efficiently and effectively.However, curved paths were a problem because the machine tool had to be programmed to undertake a series of horizontal and vertical steps to produce a curve. The shorter the straight lines making up the steps, the smoother is the curve, Each line segment in the steps had to be calculated.This problem led to the development in 1959 of the Automatically Programmed Tools (APT) language. This is a special programming language for NC that uses statements similar to English language to define the part geometry, describe the cutting tool configuration, and specify the necessary motions. The development of the APT language was a major step forward in the fur ther development from those used today. The machines had hardwired logic circuits. The instructional programs were written on punched paper, which was later to be replaced by magnetic plastic tape. A tape reader was used to interpret the instructions written on the tape for the machine. Together, all of this represented a giant step forward in the control of machine tools. However, there were a number of problems with NC at this point in its development.A major problem was the fragility of the punched paper tape medium. It was common for the paper tape containing the programmed instructions to break or tear during a machining process. This problem was exacerbated by the fact that each successive time a part was produced on a machine tool, the paper tape carrying the programmed instructions had to be rerun through the reader. If it was necessary to produce 100 copies of a given part, it was also necessary to run the paper tape through the reader 100 separate tines. Fragile paper tapes simply could not withstand the rigors of a shop floor environment and this kind of repeated use.This led to the development of a special magnetic plastic tape. Whereas the paper carried the programmed instructions as a series of holes punched in the tape, the plastic tape carried the instructions as a series of magnetic dots. The plastic tape was much stronger than the paper tape, which solved the problem of frequent tearing and breakage. However, it still left two other problems.The most important of these was that it was difficult or impossible to change the instructions entered on the tape. To made even the most minor adjustments in a program of instructions, it was necessary to interrupt machining operations and make a new tape. It was also still necessary to run the tape through the reader as many times as there were parts to be produced. Fortunately, computer technology became a reality and soon solved the problems of NC associated with punched paper and plastic tape.The development of a concept known as direct numerical control (DNC) solved the paper and plastic tape problems associated with numerical control by simply eliminating tape as the medium for carrying the programmed instructions. In directnumerical control, machine tools are tied, via a data transmission link, to a host computer. Programs for operating the machine tools are stored in the host computer and fed to the machine tool an needed via the data transmission linkage. Direct numerical control represented a major step forward over punched tape and plastic tape. However, it is subject to the same limitations as all technologies that depend on a host computer. When the host computer goes down, the machine tools also experience downtime. This problem led to the development of computer numerical control.3 TurningThe 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 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, 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 turrets 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 screw machine. Quantities less 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 on material turned, tooling , and feeds and speeds employed, minimum tolerances that can be held on automatic tracer lathes are not necessarily the most economical tolerances.In some cases, 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.中文译文1.车床车床主要是为了进行车外圆、车端面和镗孔等项工作而设计的机床。