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第4章 机床夹具设计(5)

第4章 机床夹具设计(5)
如定位销与夹具体的配合可取 H或7 H 7 n6 r6
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4.6 机床夹具的设计方法
4.6.4 夹具精度的验算 1.工件在夹具中的装夹误差
定位误差 + 夹紧误差 2.夹具的对定误差 夹具在机床上的对定包括: (1)夹具的定位——夹具在机床上的定位(对切削成形运动) (2)夹具的对刀——夹具对刀具的对准
品改型和加工对象变换而造成夹具报废。 ❖ 节省设计和制造夹具所用工时费用、材料和相关费用。 ❖ 缩短了生产准备周期。 2.组合夹具元件精度高,容易满足加工精度,保证产品质量。 3.减少夹具库存量,改善仓库的管理工作。 4.可以扩大使用范围——组合夹具元件与部分自制专用件组
合,可以组装出通用可调整夹具。

通用基本部分
成 可调整部分
夹具体、传动装置、操纵机构, 使用中固定不变,通用。
定位、夹紧、导向等元件,不同 零件加工时需要调整和更换。
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4.4 可调整夹具的设计
4.4.1 可调整夹具的特点 在加工一组不同形状和加工要求的工件时,可以通过调整、更
换部分元件组成所需要的夹具→减少了夹具重复设计,降低
4.绘制夹具零件图 画出夹具中非标零件图,并按夹具装配图的要求确定零件的 尺寸、公差及技术要求。 ——尺寸及公差、形位公差、表面粗糙度等标注要完整、正确。
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4.6 机床夹具的设计方法
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4.6 机床夹具的设计方法
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4.6 机床夹具的设计方法
4.6.2 确定和标注夹具总图上有关尺寸和技术要求 一、夹具总图上应标注的尺寸、配合和技术要求 分为五类: 1.夹具的最大轮廓尺寸:夹具的长、宽、高
型槽的配合; ❖ 定位元件至夹具定位面尺寸、公差及位置公差(⊥、∥); ❖ 用找正法调整夹具在机床上的位置时,应标注定位元件至找

汽车焊接夹具设计外文文献翻译

汽车焊接夹具设计外文文献翻译

汽车焊接夹具设计外文文献翻译(含:英文原文及中文译文)文献出处:Semjon Kim.Design of Automotive Welding Fixtures [J]. Computer-Aided Design, 2013, 3(12):21-32.英文原文Design of Automotive Welding FixturesSemjon Kim1 AbstractAccording to the design theory of car body welding fixture, the welding fixture and welding bus of each station are planned and designed. Then the fixture is modeled and assembled. The number and model of the fixture are determined and the accessibility is judged. Designed to meet the requirements of the welding fixture.Keywords: welded parts; foundation; clamping; position1 IntroductionAssembly and welding fixtures are closely related to the production of high-quality automotive equipment in automotive body assembly and welding lines. Welded fixtures are an important part of the welding process. Assembly and welding fixtures are not only the way to complete the assembly of parts in this process, but also as a test and calibration procedure on the production line to complete the task of testing welding accessories and welding quality. Therefore, the design and manufacture ofwelding fixtures directly affect the production capacity and product quality of the automobile in the welding process. Automotive welding fixtures are an important means of ensuring their manufacturing quality and shortening their manufacturing cycle. Therefore, it is indispensable to correctly understand the key points of welding fixture design, improve and increase the design means and design level of welding fixtures, and improve the adjustment and verification level of fixtures. It is also an auto manufacturing company in the fierce competition. The problem that must be solved to survive.The style of the car is different from that of the car. Therefore, the shape of the welding jig is very different. However, the design, manufacture, and adjustment are common and can be used for reference.2. Structural design of welding fixtureThe structure design of the welding fixture ensures that the clip has good operational convenience and reliable positioning of the fixture. Manufacturers of welding fixtures can also easily integrate adjustments to ensure that the surfaces of the various parts of the structure should allow enough room for adjustments to ensure three-dimensional adjustment. Of course, under the premise of ensuring the accuracy of the welding jig, the structure of the welding jig should be as simple as possible. The fixture design is usually the position of all components on the fixture is determined directly based on the design basis, and ultimately ensure thatthe qualified welding fixture structure is manufactured. According to the working height, the height of the fixture bottom plate can be preliminarily determined, that is, the height of the fixture fixing position. The welding fixture design must first consider the clamping method. There are two types, manual and pneumatic. Manual clamping is generally suitable for small parts, external parts, and small batches of workpieces. For large body parts, planning in the production line, automation High-demand welding fixtures should be pneumatically clamped. Automobile production is generally pneumatically clamped, and manual mass clamping can be used as auxiliary clamping. This can reduce costs accordingly. Some manual clamping products already have standard models and quantities, which can be purchased in the market when needed. For some devices, pneumatic clamping is specified, but if pneumatic clamping is used, the workpiece may be damaged. Therefore, it is possible to manually press the place first to provide a pneumatic clamping force to clamp the workpiece. This is manual-pneumatic. . The fixture clamping system is mounted on a large platform, all of which are fixed in this welding position to ensure that the welding conditions should meet the design dimensions of the workpiece coordinate system positioning fixture, which involves the benchmark.3. Benchmarks of assembly and welding fixtures and their chosen support surfaces3.1 Determination of design basisIn order to ensure that the three-dimensional coordinates of the automatic weldment system are consistent, all welding fixtures must have a common reference in the system. The benchmark is the fixture mounting platform. This is the X, Y coordinate, each specific component is fixed at the corresponding position on the platform, and has a corresponding height. Therefore, the Z coordinate should be coordinated, and a three-dimensional XYZ coordinate system is established. In order to facilitate the installation and measurement of the fixture, the mounting platform must have coordinates for reference. There are usually three types. The structure is as follows:3.1.1 Reference hole methodThere are four reference holes in the design of the installation platform, in which the two directions of the center coordinates of each hole and the coordinates of the four holes constitute two mutually perpendicular lines. This is the collection on the XY plane coordinate system. The establishment of this benchmark is relatively simple and easy to process, but the measurements and benchmarks used at the same time are accurate. Any shape is composed of spatial points. All geometric measurements can be attributed to measurements of spatial points. Accurate spatial coordinate acquisition is therefore the basis for assessing any geometric shape. Reference A coordinated direction formed by oneside near two datums.3.1.2 v-type detection methodIn this method, the mounting platform is divided into two 90-degree ranges. The lines of the two axes make up a plane-mounted platform. The plane is perpendicular to the platform. The surface forms of these two axis grooves XY plane coordinate system.3.1.3 Reference block methodReference Using the side block perpendicular to the 3D XYZ coordinate system, the base of a gage and 3 to 4 blocks can be mounted directly on the platform, or a bearing fixing fixture platform can be added, but the height of the reference plane must be used to control the height , must ensure the same direction. When manufacturing, it is more difficult to adjust the previous two methods of the block, but this kind of measurement is extremely convenient, especially using the CMM measurement. This method requires a relatively low surface mount platform for the reference block, so a larger sized mounting platform should use this method.Each fixture must have a fixed coordinate system. In this coordinate system, its supporting base coordinate dimensions should support the workpiece and the coordinates correspond to the same size. So the choice of bearing surface in the whole welding fixture system 3.2When the bearing surface is selected, the angle between the tangentplane and the mounting platform on the fixed surface of the welding test piece shall not be greater than 15 degrees. The inspection surface should be the same as the welded pipe fittings as much as possible for the convenience of flat surface treatment and adjustment. The surface structure of the bearing should be designed so that the module can be easily handled, and this number can be used for the numerical control of the bearing surface of the product. Of course, designing the vehicle body coordinate point is not necessarily suitable for the bearing surface, especially the NC fixture. This requires the support of the fixture to block the access point S, based on which the digital surface is established. This surface should be consistent with the supported surface. So at this time, it is easier and easier to manufacture the base point S, CNC machining, precision machining and assembly and debugging.3.2 Basic requirements for welding fixtureIn the process of automobile assembly and production, there are certain requirements for the fixture. First, according to the design of the automobile and the requirements of the welding process, the shape, size and precision of the fixture have reached the design requirements and technical requirements. This is a link that can not be ignored, and the first consideration in the design of welding fixture is considered. When assembling, the parts or parts of the assembly should be consistent with the position of the design drawings of the car and tighten with the fixture.At the same time, the position should be adjusted to ensure that the position of the assembly parts is clamped accurately so as to avoid the deformation or movement of the parts during the welding. Therefore, this puts forward higher requirements for welding jig. In order to ensure the smooth process of automobile welding and improve the production efficiency and economic benefit, the workers operate conveniently, reduce the strength of the welder's work, ensure the precision of the automobile assembly and improve the quality of the automobile production. Therefore, when the fixture design is designed, the design structure should be relatively simple, it has good operability, it is relatively easy to make and maintain, and the replacement of fixture parts is more convenient when the fixture parts are damaged, and the cost is relatively economical and reasonable. But the welding fixture must meet the construction technology requirements. When the fixture is welded, the structure of the fixture should be open so that the welding equipment is easy to close to the working position, which reduces the labor intensity of the workers and improves the production efficiency.4. Position the workpieceThe general position of the workpiece surface features is determined relative to the hole or the apparent positioning reference surface. It is commonly used as a locating pin assembly. It is divided into two parts: clamping positioning and fixed positioning. Taking into account thewelding position and all welding equipment, it is not possible to influence the removal of the final weld, but also to allow the welding clamp or torch to reach the welding position. For truly influential positioning pins and the like, consider using movable positioning pins. In order to facilitate the entry and exit of parts, telescopic positioning pins are available. The specific structure can be found in the manual. The installation of welding fixtures should be convenient for construction, and there should be enough space for assembly and welding. It must not affect the welding operation and the welder's observation, and it does not hinder the loading and unloading of the weldment. All positioning elements and clamping mechanisms should be kept at a proper distance from the solder joints or be placed under or on the surface of the weldment. The actuator of the clamping mechanism should be able to flex or index. According to the formation principle, the workpiece is clamped and positioned. Then open the fixture to remove the workpiece. Make sure the fixture does not interfere with opening and closing. In order to reduce the auxiliary time for loading and unloading workpieces, the clamping device should use high-efficiency and quick devices and multi-point linkage mechanisms. For thin-plate stampings, the point of application of the clamping force should act on the bearing surface. Only parts that are very rigid can be allowed to act in the plane formed by several bearing points so that the clamping force does not bend the workpiece or deviate from thepositioning reference. In addition, it must be designed so that it does not pinch the hand when the clamping mechanism is clamped to open.5. Work station mobilization of welding partsMost automotive solder fittings are soldered to complete in several processes. Therefore, it needs a transmission device. Usually the workpiece should avoid the interference of the welding fixture before transmission. The first step is to lift the workpiece. This requires the use of an elevator, a crane, a rack and pinion, etc. The racks and gears at this time Structure, their structural processing, connection is not as simple as the completion of the structure of the transmission between the usual connection structure of the station, there are several forms, such as gears, rack drive mechanism, transmission mechanism, rocker mechanism, due to the reciprocating motion, shake The transfer of the arm mechanism to the commissioning is better than the other one, so the common rocker arm transfer mechanism is generally used.6 ConclusionIn recent years, how to correctly and reasonably set the auxiliary positioning support for automotive welding fixtures is an extremely complicated system problem. Although we have accumulated some experience in this area, there is still much to be learned in this field. Learn and research to provide new theoretical support for continuous development and innovation in the field of welding fixture design. Withthe development of the Chinese automotive industry, more and more welding fixtures are needed. Although the principle of the fixture is very simple, the real design and manufacture of a high-quality welding fixture system is an extremely complicated project.中文译文汽车焊接夹具的设计Semjon Kim1摘要依据车体焊装线夹具设计理论, 对各工位焊接夹具及其焊装总线进行规划、设计, 之后进行夹具建模、装配, 插入焊钳确定其数量、型号及判断其可达性,最终设计出符合要求的焊接夹具。

夹具设计外文翻译

夹具设计外文翻译

Application and developmentOf case based reasoning in fixture designFixtures are devices that serve as the purpose of holding the workpiece securely and accurately, and maintaining a consistent relationship with respect to the tools while machining. Because the fixture structure depends on the feature of the product and the status of the process planning in the enterprise, its design is the bottleneck during manufacturing, which restrains to improve the efficiency and leadtime. And fixture design is a complicated process, based on experience that needs comprehensive qualitative knowledge about a number of design issues including workpiece configuration, manufacturing processes involved, and machining environment. This is also a very time consuming work when using traditional CAD tools (such as Unigraphics, CATIA or Pro/E), which are good at performing detailed design tasks, but provide few benefits for taking advantage of the previous design experience and resources, which are precisely the key factors in improving the efficiency. The methodology of case based reasoning (CBR) adapts the solution of a previously solved case to build a solution for a new problem with the following four steps: retrieve, reuse, revise, and retain [1]. This is a more useful method than the use of an expert system to simulate human thought because proposing a similar case and applying a few modifications seems to be self explanatory and more intuitive to humans .So various case based design support tools have been developed for numerous areas[2-4], such as in injection molding and design, architectural design, die casting die design, process planning, and also in fixture design. Sun used six digitals to compose the index code that included workpiece shape, machine portion, bushing, the 1st locating device, the 2nd locating device and clamping device[5]. But the system cannot be used for other fixture types except for drill fixtures, and cannot solve the problem of storage of the same index code that needs to be retained, which is very important in CBR[6].1. Construction of a Case Index and Case Library1.1 Case indexThe case index should be composed of all features of the workpiece, which are distinguished from different fixtures. Using all of them would make the operation in convenient. Because the forms of the parts are diverse, and the technology requirements of manufacture in the enterprise also develop continuously, lots of features used as the case index will make the search rate slow, and the main feature unimportant, for the reason that the relative weight which is allotted to every feature must diminish. And on the other hand, it is hard to include all the features in the case index.1.2 Hierarchical form of CaseThe structure similarity of the fixture is represented as the whole fixture similarity, components similarity and component similarity. So the whole fixture case library, components case library, component case library of fixture are formedcorrespondingly. Usually design information of the whole fixture is composed of workpiece information and workpiece procedure information, which represent the fixture satisfying the specifically designing function demand. The whole fixture case is made up of function components, which are described by the function components’ names and numbers. The components case represents the members. (function component and other structure components,main driven parameter, the number, and their constrain relations.) The component case (the lowest layer of the fixture) is the structure of function component and other components. In the modern fixture design there are lots of parametric standard parts and common non standard parts. So the component case library should record the specification parameter and the way in which it keeps them.2. Strategy of Case RetrievalIn the case based design of fixtures ,the most important thing is the retrieval of the similarity, which can help to obtain the most similar case, and to cut down the time of adaptation. According to the requirement of fixture design, the strategy of case retrieval combines the way of the nearest neighbor and knowledge guided. That is, first search on depth, then on breadth; the knowledge guided strategy means to search on the knowledge rule from root to the object, which is firstly searched by the fixture type, then by the shape of the workpiece, thirdly by the locating method. For example, if the case index code includes the milling fixture of fixture type, the search is just for all milling fixtures, then for box of workpiece shape, the third for 1plane+ 2pine of locating method. If there is no match of it, then the search stops on depth, and returns to the upper layer, and retrieves all the relative cases on breadth.2.1 Case adaptationThe modification of the analogical case in the fixture design includes the following three cases:1) The substitution of components and the component;2) Adjusting the dimension of components and the component while the form remains;3) The redesign of the model.If the components and component of the fixture are common objects, they can be edited, substituted and deleted with tools, which have been designed.2.2 Case storageBefore saving a new fixture case in the case library, the designer must consider whether the saving is valuable. If the case does not increase the knowledge of the system, it is not necessary to store it in the case library. If it is valuable, then the designer must analyze it before saving it to see whether the case is stored as a prototype case or as reference case. A prototype case is a representation that can describe the main features of a case family. A case family consists of those cases whose index codes have the same first 13 digits and different last three digits in the case library. The last three digits of a prototype case are always “000”. A reference case belongs to the same family as the prototype case and is distinguished by the different last three digits.From the concept that has been explained, the following strategies are adopted:1) If a new case matches any existing case family, it has the same first 13 digits as an existing prototype case, so the case is not saved because it is represented well by the prototype case. Or is just saved as a reference case (the last 3 digits are not “000”, and not the same with others) in the case library.2) If a new case matches any existing case family and is thought to be better at representing this case family than the previous prototype case, then the prototype case is substituted by this new case, and the previous prototype case is saved as a reference case.3) If a new case does not match any existing case family, a new case family will be generated automatically and the case is stored as the prototype case in the case library.3. ConclusionCBR, as a problem solving methodology, is a more efficient method than an expert system to simulate human thought, and has been developed in many domains where knowledge is difficult to acquire. The advantages of the CBR are as follows: it resembles human thought more closely; the building of a case library which has self learning ability by saving new cases is easier and faster than the building of a rule library; and it supports a better transfer and explanation of new knowledge that is more different than the rule library. A proposed fixture design framework on the CBR has been implemented by using Visual C ++, UG/Open API in U n graphics with Oracle as database support, which also has been integrated with the 32D parametric common component library, common components library and typical fixture library. The prototype system, developed here, is used for the aviation project, and aids the fixture designers to improve the design efficiency and reuse previous design resources.基于事例推理的夹具设计研究与应用夹具是以确定工件安全定位准确为目的的装置,并在加工过程中保持工件与刀具或机床的位置一致不变。

夹具设计中英文对照

夹具设计中英文对照

Optimization of fixture design with consideration of thermal deformation inface milling考虑端铣中热变形的最佳化夹具设计Huang, YingAbstract摘要Effective methods of fixture design are proposed to reduce machining error caused by cutting heat in face milling. Experiments show that thermal effect is critical to final error in the finish cut and that it dominates cutting accuracy. Therefore, a mathematical model is structured of the cutting heat source on behalf of the cutting tool, and the flatness error generation process in face finishing is demonstrated by computational simulation based on the moving cutting heat source model with FEW Concerning surface flatness due to the moving cutting heat source for relatively thin plate-shaped workpieces, different methodologies have been proposed to reduce flatness error, namely, the application of additional supports and optimization of the fixturing support layout. Cutting experiments and computational analyses show the effectiveness of the additional supports and the optimization methodology applied on the fixture design in view of flatness error due to cutting heat. The proposed methodologies are applicable and beneficial to improve cutting accuracy not only of plate-shaped workpieces but also of other geometry workpieces.用于减小端铣中因切削热而引起的加工误差的有效的夹具设计方法已经被提出。

机床刀具设计机械加工工艺夹具外文文献翻译、中英文翻译、外文翻译

机床刀具设计机械加工工艺夹具外文文献翻译、中英文翻译、外文翻译

英语原文:Design Of Tool Machine PropResearch significanceThe original knife machine control procedures are designed individually, not used tool management system, features a single comparison, the knife only has to find the tool knife, knife positioning the shortest path, axis tool change, but does not support large-scale tool.Automatic knife in the knife election, in the computer memory knife-election on the basis of using the Siemens 840 D features, and the election procedures knife more concise, and complete the space Daotao View. ATC use the knife rapid completion of STEP-7 programming, and have been tested in practice. In the positioning of the knife, PLC controlled modular design method, which future production of similar machines will be very beneficial, it is easy to use its other machine. Automatic tool change systems will be faster growth, reduced tool change time, increase the positioning accuracy tool is an important means to help NC technology development.Tool and inventory components of modern production is an important link in the management, especially for large workshop management. The traditional way of account management, and low efficiency, high error rate, and not sharing information and data, tools and the use of state can not track the life cycle, are unable to meet the current information management needs. With actual production, we have to establish a workshop tool for the three-dimensional tool storage system to meet the knife workshop with auxiliary storage and management needs.The system uses optimization technology, a large number of computer storage inventory information, timely, accurate, and comprehensive tool to reflect the inventory situation. The entire system uses a graphical interface, man-machine dialogue tips from the Chinese menu, select various functions can be realized and the importation of all kinds of information. Management system using online help function. Through the workshop management, network management and sharing of information. Have automated inventory management, warehousing management tool, a tool for the management and statistical functions.1.System components and control structureThe entire system, including the structure and electrical machinery control systems.1.1.1Mechanical structure and working principleTool from the stent, drive, drive system, Turret, shielding, control system, and electrical components. Support from the column, beam, the upper and lower guide Central track, and track support component.1) Drive for the system chosen VVVF method. Cone used brake motors, with VVVF by Cycloid reducer through sprocket drive.2) Drag a variable frequency drive system and control technology. VVVF adopted, will speed drive shaft in the normal range adjustment to control the speed rotary turret to 5 ~ 30mm in, the drive shaft into two, two under through sprocket, the two profiled rollers Chain driven rotating shelves. Expansion chain adopted by the thread tight regulation swelling, swelling the regular way. - Conditioned, under the same chain-of-conditioning, so that the chain of uniform.3) Turret and shields the entire total of 14 independent Turret. 13 of them as a socket-Turret, as adrawer-Turret, each Turret back through the pin and, under the conveyor chain link chain plate, installed at the bottom roller, chain driven rotating turret rotation along the track. Outlet-Turret and BT50-BT40 Turret Turret two kinds of forms. To strengthen management, security, landscaping modeling, shelf peripherals and shields. Turret-drawer drawer placed at six other Des V oeux a knife, can be categorized with some of knife auxiliary equipment, such as bits, such as turning tools.1.1.2.Electrical Control SystemThis tool storage systems is the main electrical control their shelves for operational control and position control. Operational control equipment, including operation of the start of braking control. Position Control is the main location and address of the shelves for testing. Control system as shown in Figure 1.图 1 Tool Control System for the1) Electric Transmission horizontal rotary tool storage systems are the mechanical movements are repeated short-term work system. And the run-time system needs some speed, speed transmission needs, the system will use VVVF method can be used simple structure, reliable operation of the motor and frequency inverter.2) Control of the system is divided into two kinds of manual control and automatic control, manual control as a general reserve and debugging methods of work; ways to the system control computer (IPC) and the control unit (inverter contactor , etc.) consisting of a control system.3) location and positioning accuracy of the system automatically identify the site and location using a detection device as proximity switches, relays through the plate-point isolation and the number plate recorded close to the switching signal acquisition and operation of Hutchison with a Optimal Path addressable identify the current location and shelves of the purpose of the shelf location. In order to enable a more accurate positioning system, adopted two photoelectric switches, to detect the two shelves of the two films.1.2.The functions of the knifeknife The is the role of reserves a certain number of tools, machine tool spindle in hand to achieve the fungibility a disc cutter knife is the type of library, the chain knives, and other means, in the form of the knife and capacity according to the Machine Tool to determine the scope of the process.mon typesThe knife is a tool storage devices, the common knife mainly in the following forms:(1) the turret knifeIncluding the first level turret vertical turret and the first two, see Figure 2.6 a) and b):(2) the disc cutterDisc knife in the library with discoid knife, cutting tool along See how vertical arrangement (including radial and axial from knife from knife), along See how radial array into acute or arranged in the form of the knife. Simple, compact, more applications, but are ring-cutter, low utilization of space. Figure 2.7 a) to c). If the knife storage capacity must be increased to increase the diameter of the knife, then the moment of inertia also increased correspondingly, the election campaign long knife. Tool number not more than 32 general. Cutter was multi-loop order of the space utilization knife, but inevitably given the knife from complex institutions, applicable to the restricted space Machine Tool storage capacity and more occasions. Two-disc structure is two smaller capacity knife on both sides of the sub-spindle place, more compact layout, the number of certificates corresponding increase knife, apply to small and medium-sized processing center.(3) the chain knifeIncluding single-and multi-ring chain ring chain, chain link can take ma ny forms change, see Figure 2.8 a) to c), the basic structureFeatures: knife apply to thelarger capacity of theoccasion, the space of thesmall number of generallyapplicable to the tool in the30-120. Only increase thelength of the chain tool willincrease the number shouldnot be increasedcircumferential speed of itsmoment of inertia of theknife does not increase thedisc as large.(4) linear combination knife and the knife libraryThe linear knife simple structure in Figure 2.9, tool single order, the capacity of small knife, used for CNC lathe and drill press on. Because the location of fixed knife, ATC completed action by the spindle without manipulator. The cutter knife is generally the turret combination turret with a combination of the disc cutter knife and the chain combination. Every single knife the knife certificates of smaller, faster tool change. There are also some intensive drum wheel, and the lattice-type magazine for the knife, the knife-intensive though. Small footprint, but because of structural constraints, basically not used for single processing center, the concentration used for FMS for the knife system.1.4 Tool storage capacityTool storage capacity of the first to consider the needs of processing, from the use of point of view, generally 10 to 40 knives, knife will be the utilization of the high, and the structure is compact.1.5 Tool options(1) choose to order processing tool according to the order, followed Add to the knife every knife in the Block. Each tool change, the order of rotation of a cutter knife on location, and remove the need knives, has been used by the cutter knife can be returned to the original Block, can also order Add Block, a knife. However, as the knife in the tool in different processes can not be repeated use of the knife must increase the capacity and lower utilization rate.(2) most of the arbitrary choice of the current system of using arbitrary NC election knives, divided into Daotao coding, coding and memory-cutter, three. Daotao coding tool code or knives or Daotao need to install the code used to identify, in accordance with the general principle of binary coding coding. Tool knife election coding method uses a special knife handle structure, and each of the coding tool. Each of the tool has its own code, thereby cutting tool can be in different processes repeatedly used, not to replace the tool back at the original knife, the knife capacity can be reduced accordingly. Memory-election this paper knife, in this way can knives and knife in the position corresponding to the Daotao memory of the PLC in the NC system, no matter which tool on the Inner knife, tool information is always there in mind, PLC . On the knife with position detection devices, will be the location of each Daotao. This tool can be removed and sent back to arbitrary. On the knife is also a mechanical origin, every election, the nearest knife selection.1.6.Control of the knife(1) the knife as a system to control the positioning axis. In the ladder diagram in accordance with the instructions for computing T code comparison of the output angle and speed of instructions to the knife the knife servo drive servo motor. Tool storage capacity, rotation speed, and / deceleration time, and other system parameters can be set in such a manner free from any outside influence positioning accurate and reliable but the cost is higher.(2) knife from the hydraulic motor drives, fast / slow the points, with proximity switches count and positioning. In comparison ladder diagram of the current storage system knife (knife spindle) and goals knife (pre-knife) and computing, then output rotation instructions, judging by the shortest path rotation in place. This approach requires sufficient hydraulic power and electromagnetic valve knife the rotational speed can be adjusted through the throttle. But over time may be oily hydraulic, oil temperature and environmental factors impact the change in velocity and accuracy. Not generally used in large and medium-sized machine tool change frequently.(3) the knife from AC asynchronous motor driven cam mechanism (Markov institutions), with proximity switches count, which means stable operation, and generally accurate and reliable positioning cam used in conjunction with a mechanical hand, ATC fast-positioning.2. ATC, the main types, characteristics, and the scope of application2.1 Auto Rotary ToolRotary Tool automatically on the useof CNC machine tool is a simpleinstallation of automatic tool change, theQuartet and 47.60 Turret Tool variousforms, such as rotary turret were installedon four, six or more of the Tool , NCinstructions by ATC. Rotary Tool has twovertical and horizontal, relatively simplestructure, applicable to economic CNClathe.Rotary Tool in the structure must havegood strength and stiffness, resistance tobear rough Cutting Tool in the cuttingforce and reduce the role of deformationand improve processing accuracy.Rotating Tool to choose reliablepositioning programme structure andreasonable position, in order to ensure thateach rotary turret to a higher position afterrepeated positioning accuracy (typically0.001 to 0.005mm). Figure 2.1 shows thespiral movements of the Quartet Turret.Auto Rotary Tool in the simplest ofATC, is 180 º rotary ATC devices, asshown in Figure 2.2 ATC instructionsreceived, the machine control system put ATC spindle control to the designated location at the same time, the tool movement to the appropriate location, ATC, with the rotary axis and at the same time, the knives matching tool; drawbars from Spindle Cutting Tools rip, ATC, will be the tool from their position removed; ATC, 180 º rotary tool spindle and the tool and tool away; ATC, the Rotary At the same time, the tool refocusing its position to accept Spindle removed from the cutting tool; Next, ATC, will be replaced with the cutter knives were unloaded into the spindle and tool: Finally, back to the original ATC, "standby" position. At this point, ATC completed procedures to continue to run. This ATC, the main advantage of simple structure, the less movement, fast tool change. The main disadvantage is that knives must be kept in parallel with the axis of the plane, and after the home side compared to the tool, chip and liquid-cutting knife into the folder, it is necessary to the tool plus protection. Cone knife folder on the chip will cause ATC error, or even damage knife folders, and the possibility of spindle. Some processing centre at the transfer, and the tool side. When the ATC command is called, the transfer-cutter knives will be removed, the machine go forward, and positioning with the ATC, in line with the position. 180 º "Rotary ATC devices can be used horizontal machine, can also be used for vertical machining centers.2. 2 ATC head-turret installedWith rotating CNC machine tool often used such ATC devices, with a few turret head spindle, each with a spindle on both knives, the first tower interim process can be automatic tool change-realization. The advantage is simple structure, tool change time is short, only about 2 s. However, due to spatial constraints, the number of spindle can not be too much, usually only apply to processes less, not to high precision machine tools, such as the NC drill, such as CNC milling machine. In recent years there has been a mechanical hand and the turret head with a knife for the automatic tool change ATC devices, as shown in Figure 2.3. It is in fact a turret head ATC, and the knife-ATC device combination. The principle is as follows:5 turret on the first two tool spindle 3 and 4, when using the tool spindle 4 processing tool, the manipulator 2 will be the next step to the need for the tool does not work on the tool spindle 3 until after the completion of this process , the first rotary turret 180 º, ATC completed. ATC most of their time and processing time coincidence, the only real tool change time turret transposition of the first time, this approach mainly used for ATC and NC NC drilling file bed.2. 3.Daidao system for the automatic tool changeFigure 2.4 shows the knife and the whole machine tool CNC machine tools for the appearance of Fig. Figure 2.5 shows the knife and split-type machine to the appearance of CNC machine tool plans.At this point, knife storage capacity, a heavier tool can, and often additional transport unit to complete the knife between the spindle and cutting tool transport.Daidao the knife from the ATC, the election knives, automatic loading and unloading machine tool and tool exchange institutions (manipulator), composed of four parts, used widely.Tool Automatic Tool Change the manipulator system, the whole process more complicated ATC. We must first used in the processing of all installed in the standard tool on the knife handle in the machine outside the pre-size, according to a certain way Add to the knife. ATC, selected first in the knife knife, and then from ATC, from the knife from the knife or spindle, exchange, the new knife into the spindle, the old knife back into the knife.ATC, as the former two knives to accommodate a limited number can not be too many, can not meet the needs of complex parts machining, CNC machine tool Automatic Tool Change Daidao the use of the automatic tool change devices. The knife has more capacity, both installed in the spindle box side or above. As for the automatic tool change Daidao device CNC machine tool spindle box only a spindle, spindle components to high stiffness to meet the machining requirements. The number of establishments in larger knife, which can meet the more complex parts of the machining processes, significantly improving productivity. Daidao system for the automatic tool change applied to drilling centres and CNC machining centers. The comparison drawn Daidao automatic tool change system is the most promising.3.PLC control of the knife random mode of election 3. 1Common methods of automatic election knifeAutomatic control of the knife CNC refers to the system after the implementation of user instructions on the knife library automation process, including the process to find knives and automatic tool change [(63,71]. CNC Machining Center device (CNC) directive issued by the election knife , a knife, the tool required to take the knife position, said the election automatic knife. automatically elected knife There are two ways: random sequence election knives and knife election method.3.1.1 order election knifeTool Selection order is the process tool according to the sequence of the insert knife, the use of knives in order to take place, used knives back at the original knife, can also order Add Block, a knife. In this way, no need Tool identification devices, and drive control is a relatively simple, reliable and can be used directly from the points of the knife machinery to achieve. But the knives in each of the tool in different processes can not be reused, if the tool is installed in accordance with the order of the knife, there will be serious consequences. The need to increase the number of knives and knife the capacity of the tool and reduce the utilization of the knife.3.1.2Random election knifeRandom election under the knife is arbitrary instructions to select the required tools, then there must be tool identification devices. Tool knife in the library do not have the processing in accordance with the order of the workpiece can be arbitrary storage. Each of the tool (or knife blocks) are for a code, automatic tool change, the rotary cutter, every tool have been the "tool identification device" acceptable identification. When CNC tool code and the code in line with directives of the tool selected, the rotary cutter knives will be sent to the ATC position, waiting to grab manipulator. Random knife election is the advantage of the cutter knife in the order has nothing to do with the processing sequence, the same tool can be used repeatedly. Therefore, the relatively small number of knives, knife the corresponding smaller. Random elections knife on the tool must be coded to identify. There are three main coding.1. Tool coding. Adopt special knife handle structure coding, the drawbars on the knife handle back-end packages such as spacing of the coding part of the lock-nut fixed. Coding diameter ring diameter of a size two, respectively, said that binary "1" and "0" to the two rings are different, can be a series of code. For example, there are six small diameter of the ring can be made to distinguish between 63 (26-1 = 63) of the coding tool. All of 0 normally not allowed to use the code, to avoid the cutter knife Block did not confuse the situation.2. Knife Block coding. On the knife Block coding, coding tool, and tool into line with the number of knives in the Block. ATC knife when the rotation, so that each knife seats followed through knowledge knife, knife found blocks, knives stopped the rotation. At this time there is no knife handle encoding part of the knife handle simplified.3. Annex coding methods. This style of coding keys, coded cards, coding and coding-disc, which is the most widely used coding keys. First toknives are attached to a tool of the show wrapped coding keys, and when the cutter knife to the store at knife in, so put the number of keys to remember knife Block Road, will be inserted into key to the coding Block next to the key hole in the seat for the knife to the numbers. ConclusionFocused on in today's manufacturing environment tool storage and management of new models and methods, practical application of good results in systems integration and optimization, and other aspects of operations will be further explored, so that it has a higher theoretical and practical level.译文:机床刀具设计课题研究意义机床原来的刀库控制程序是单独设计的,没有采用刀具管理系统,功能也比较单一,只实现了刀库刀具的找刀、刀库最短路径定位、主轴换刀,而且不支持大型刀具。

泵体(II)零件机械加工工艺和专用夹具设计-外文翻译

泵体(II)零件机械加工工艺和专用夹具设计-外文翻译

本科生毕业设计 (论文)
外文翻译
原文标题An intelligent fixture design method based on
smart modular fixture unit
译文标题基本的加工工序—切削,镗削和铣削
作者所在系别机电工程学院
作者所在专业机械设计制造及自动化
作者所在班级
作者姓名
作者学号
指导教师姓名
指导教师职称
完成时间
注:1. 指导教师对译文进行评阅时应注意以下几个方面:①翻译的外文文献与毕业设计(论文)的主题是否高度相关,并作为外文参考文献列入毕业设计(论文)的参考文献;②翻译的外文文献字数是否达到规定数量(3 000字以上);③译文语言是否准确、通顺、具有参考价值。

2. 外文原文应以附件的方式置于译文之后。

专业夹具设计全英文介绍

专业夹具设计全英文介绍

26
Force comparison
Standard clamping strap M24 thread
Max. recommended torque 383Nm Max. clamping force 40kN
Hollow piston cylinder 6921-100x10 (page 26, metric catalogue) M24 thread Max. oil pressure 400 bar Clamping force 101kN
27
Mechanical or Hydraulic ?
Mechanical or Hydraulic ?
Cartridge Mount Cylinder (x8)
42-1010-04 (page F-12)
2.5 kN each 50MPa
Sequence Valve 47-0440-02 (J-3) Set at 30 MPa
22
Mechanical Forces
Clamping force with extension pieces as shown, 500N torque, µ = 0.1
Clamping force (kN)
Maximum clamping force using standard wrench
32
Oil supply to fixtures, cost comparison
A:Through pipes using flange type clamps B:Through pipes using threaded type clamps C:Through gun drilled channels & manifold mounted type

机械制造及自动化专业外文翻译--工件在夹具中的夹紧

机械制造及自动化专业外文翻译--工件在夹具中的夹紧

外文原文:1.Machining Technology Handbook, Volume 1 [M]. Muong for Machinery Industry Press, 1991Work piece in the clamping fixtureIn the machining process, the work piece by the cutting force, centrifugal force, inertia force, such as the role of, in order to ensure that these external force, the work piece can remain in the fixture by the positioning of the processing to determine the location of components, and should be no vibration or displacement, fixture structure should be set up reliable work piece clamping device folder will be in prison.First, the composition of clamping devicesMany different types of clamping devices, but their structures are composed of two parts.1. Power plantThe source of clamping force, one human; second is generated by a power device. The device can generate power as the power unit fixture. Commonly used in power plant are: pneumatic devices, hydraulic devices, electrical devices, electromagnetic devices, gas - liquid interaction devices and vacuum devices. Fixture as a result of manual clamping force from the human, so it does not power plants.2. Clamping partReceive and impart into the original clamping force to clamp the task force and part of the implementation of the general composition of the following agencies:1) to accept the original force of bodies. Such as handles, nuts, and used to connect the institutions, such as cylinder piston rod.2) Force the middle of delivery. Such as hinges, levers and so on.3)Clamping components. Such as plate, such as screws.Force delivery of them in the middle of the original transmission of force to the process of clamping devices can play, such as changes in the direction of force to change the size of forces, as well as the role of self-locking and so on.Second, the basic requirements for clamping deviceWithout damaging the work piece positioning accuracy, and quality assurance process under the premise of clamping devices should be enabled to:1. The size of the appropriate clamping force. It is necessary to ensure that the work piece in the whole process of its stable position, vibration small, but also so that the work piece does not produce excessive clamping deformation.2. Technology is good. The complexity of the clamping device should be suited to the production of the Program, to ensure production efficiency, its structure should be kept simple, easy to manufacture and maintenance.3. Good use. The operation of clamping device should be convenient, safe and labor-saving.Third, the basic ClampThe original force into a clamping force through the clamping body to achieve. Among the many institutions in the clamping wedge oblique, spiral, and by their eccentric combination of the most common application of clamping.(A) Wedge ClampWedge used as components or transmission of the clamping device clamping body known as the Wedge Clamp.Wedge clamping directly, the oblique wedge of the self-locking conditions are:Wedge angle smaller than the work piece Wedge, Wedge and folders between the concrete and the friction angle.Namely: a £ f1 + f2In order to ensure a reliable self-locking, manual clamping generally take a = 6 °~ 8 °. Using pneumatic or hydraulic device drivers do not need the self-locking oblique wedge, it is desirable to a = 15 ° ~ 35 °.Wedge clamp is simple in structure, than by large, self-locking features such as performance, it is widely available.(B) Helical ClampUsed as intermediate screw transmission components are collectively referred to as the clamping screw clamping body organs. Because of its simple structure, reliable clamping, common good, and as a result of the small helix angle, spiral of self-locking clamping body good, clamping force and the clamping itinerary are larger fixture on manual with the most a clamping body.1. Simple screw clamp bodyThe simplest spiral as a result of the direct use of clamping bodies pressed work piece screw head, so easy to damage the surface of the work piece under pressure, or driven rotating work piece. So often in the head with swinging Press. Press with the work piece as a result of friction between the Press and the torque is greater than the friction between the screw torque, screw together with the Press will not rotate.Clamping action slow, time-consuming loading and unloading the work piece is a single spiral Another drawback of the Clamp. To overcome this shortcoming, the rapid clamping bodies can be.2. Clamp screw plateInstitutions in the clamping, the use of spiral plate is very common, common structure of the spiral structure of a typical plate size has been standardized, the designer can refer to the relevant national standards and fixture design manual design.(C) Eccentric ClampWith eccentric pieces, directly or indirectly, the work piece clamping body, known as the eccentric clamping body. There are two types of eccentric pieces, that is, and the curve of eccentricity eccentric circle, which, due to a round eccentric structure is simple and easy to manufacture and is widely used.Eccentric clamping processing is easy to operate, rapid clamp, the disadvantage of clamping force and clamping trip are small. Not generally used in cutting force, vibration small, there is no centrifugal force of the impact of the processing.1. Round the working principle of eccentric2. Eccentric clamping round trip and paragraph3. Eccentric self-locking condition of amax £ j1 + j2Was derived: f1 ³ 2e / DWhen f = 0.1 hours, e / D ³ 20, when f = 0.15 pm, e / D ³ 14Fourth, institutions centering clampingWhen the work piece is processed by the central element of surface (axis, the center plane, etc.) for the base process, in order to enable the base to reduce the positioning error of coincidence, to be used centering clamping body.Centering centering clamping body and clamping the two functions, such as horizontal self-centering three-jaw lathe chuck is a classic example of the most commonly used.Centering centering clamping the role of institutions according to their principle, there are two types, one is relying on the transmission mechanism so that mobile speed centering clamping device in order to achieve centering clamping, such asspiral, leveraged, institutions such as wedge ; the other is the use of thin-walled elastic element force even after the elastic deformation (contraction or expansion), to achieve centering clamping, such as a spring clip drum, diaphragm chuck, bellows units, such as liquid plastic.1. Centering clamping body spiralRotary screw thread at both ends to the contrary, the same pitch. When it spins, the two V-shaped gag against the constant movement in order to achieve the centering of the work piece clamping or release. V-shaped work pieces of different shapes can shut up the replacement.Centering clamping bodies such features are: simple structure, the work trip, and general good, but the centering accuracy is not high, mainly suitable for rough or semi-finished tour of the needs of large and less demanding precision centering occasions.2. Leveraged institutions centering clampingThree-jaw self-centering leveraged trading cards, sleeve for axial movement, the circle are three fabric hook lever will rotate around the axis, the three struck the slider along the radial movement of the cards in order to promote its claws the work piece centering and clamping or release.This centering clamping rigid body, and move fast, by force multiplier, and the work trip is also characterized by relatively large, but its relatively low precision centering. Generally about Æ0.1mm, it is mainly used for rough work. Since the body can not self-locking lever, so that organizations rely on self-locking air pressure or other agencies.3. Centering clamping wedge bodiesWedge mobile folder automatically centering body claw, when the work piece surface within the hole and left the position in the fixture after the six-cylinder through the rod so that the left claw clip, due to the role of ontology on the slope, while the left claw folder to the opened outside the bulge will be centering the work piece clamping; the other hand, claw shifted to right folder, in the role of spring circle card folder under收拢claw to release the work piece.Centering clamping bodies such compact structure, usually ranging from precision centering Æ0.02mm ~ Æ0.07mm, compared with the hole for the work piece surface for positioning the base of the semi-finishing processes.4. Clip-on spring-centering clamping cylinder bodyThis centering clamping sleeve body type commonly used in the installation of the work piece.Elastic centering clamping simple structure, small size, easy to operate quickly, so a wide range of applications. Centering accuracy of its stability in between Æ0.04mm ~ Æ0.010mm. In addition to the above described centering clamping bodies, are commonly used diaphragm chuck body, corrugated centering clamping sets of institutions, as well as fluid bodies, such as plastic clamping。

专业夹具设计外文翻译.doc

专业夹具设计外文翻译.doc

译文标题精密机械加工工艺原文标题Precision Machining Technology作者Peter J. Hoffman 译名彼得·J·霍夫曼国籍美国原文出处Cengage Learning译文:在机械加工过程中,工件受到切削力、离心力、惯性力等的作用,为了保证在这些外力作用下,工件仍能在夹具中保持已由定位元件确定的加工位置,而不致发生振动或位移、夹具结构中应设置夹紧装置将工件可靠夹牢。

一、夹紧装置的组成夹紧装置的种类很多,但其结构均由两部分组成。

1 .动力装置夹紧力的来源,一是人力;二是某种装置所产生的力。

能产生力的装置称为夹具的动力装置。

常用的动力装置有:气动装置、液压装置、电动装置、电磁装置、气—液联动装置和真空装置等。

由于手动夹具的夹紧力来自人力,所以它没有动力装置。

2 .夹紧部分接受和传递原始作用力使之变为夹紧力并执行夹紧任务的部分,一般由下列机构组成:1 )接受原始作用力的机构。

如手柄、螺母及用来连接气缸活塞杆的机构等。

2)中间递力机构。

如铰链、杠杆等。

3 )夹紧元件。

如各种螺钉压板等。

其中中间递力机构在传递原始作用力至夹紧元件的过程中可以起到诸如改变作用力的方向、改变作用力的大小以及自锁等作用。

二、夹紧装置的基本要求在不破坏工件定位精度,并保证加工质量的前提下,应尽量使夹紧装置做到:1.夹紧力的大小适当。

既要保证工件在整个加工过程中其位置稳定不变、振动小,又要使工件不产生过大的夹紧变形。

2 .工艺性好。

夹紧装置的复杂程度应与生产纲领相适应,在保证生产效率的前提下,其结构应力求简单,便于制造和维修。

3 .使用性好。

夹紧装置的操作应当方便、安全、省力。

三、基本夹紧机构原始作用力转化为夹紧力是通过夹紧机构来实现的。

在众多的夹紧机构中以斜楔、螺旋、偏心以及由它们组合而成的夹紧机构应用最为普遍。

(一)紧机构 采用斜传力元紧元紧机斜楔 机构。

直接采用,斜楔条件是:斜楔的升角小于斜楔与工 件、斜 具的摩擦角之和。

机械制造专业外文翻译---壳体零件的加工工艺规程及夹具设计

机械制造专业外文翻译---壳体零件的加工工艺规程及夹具设计

中文译文:数控机床夹具的发展趋势1.国内外研究历史和现状1.2 国内机床夹具发展历史我国国内的夹具始于20世纪60年代,当时建立了面向机械行业的天津组合夹具厂,和面向航空工业的保定向阳机械厂,以后又建立了数个生产组合夹具元件的工厂。

在当时曾达到全国年产组合夹具元件800万件的水平。

20世纪80年代以后,两厂又各自独立开发了适合NC机床、加工中心的孔系组合夹具系统,不仅满足了我国国内的需求,还出口到美国等国家。

当前我国每年尚需进口不少NC机床、加工中心,而由国外配套孔系夹具,价格非常昂贵,现大都由国内配套,节约了大量外汇。

1.2国外机床夹具发展历史从国际上看俄国、德国和美国是组合夹具的主要生产国。

当前国际上的夹具企业均为中小企业,专用夹具、可调整夹具主要接受本地区和国内订货,而通用性强的组合夹具已逐步成熟为国际贸易中的一个品种。

有关夹具和组合夹具的产值和贸易额尚缺乏统计资料,但欧美市场上一套用于加工中心的夹具,通常为机床价格的1110﹩到1115﹩,而组合夹具的大型基础件尤其昂贵。

由于我国在组合夹具技术上有历史的积累和性能价格比的优势,随着我国加入WTO和制造业全球一体化的趋势,特别是电子商务的日益发展,其中蕴藏着很大的商机,具有进一步扩大出口良好前景。

1.3 国内外机床夹具发展现状国际生产研究协会的统计表明,目前中、小批多品种生产的工件品种已占工件种类总数的85%左右。

现代生产要求企业所制造的产品品种经常更新换代,以适应市场的需求与竞争。

然而,一般企业都仍习惯于大量采用传统的专用夹具,一般在具有中等生产能力的工厂,里约拥有数千甚至近万套专用夹具;另一方面,在多品种生产的企业中,每隔3~4年就要更新50~80%左右专用夹具,而夹具的实际磨损量仅为10~20%左右。

特别是近年来,数控机床、加工中心、成组技术、柔性制造系统(FMS)等新加工技术的应用,对机床夹具提出了如下新的要求:(1)能迅速而方便地装备新产品的投产,以缩短生产准备周期,降低生产成本;(2)能装夹一组具有相似性特征的工件;(3)能适用于精密加工的高精度机床夹具;(4)能适用于各种现代化制造技术的新型机床夹具;(5)采用以液压站等为动力源的高效夹紧装置,以进一步减轻劳动强度和提高劳动生产率;(6)提高机床夹具的标准化程度。

夹具设计英文文献翻译

夹具设计英文文献翻译

讨论和分析现代计算机辅助夹具设计方法Iain 波以耳、Yiming Rong,戴维布朗关键字:计算机辅助夹具设计;夹具设计;夹具设计;夹具确认;装备设计;元件设计摘要现代市场是一个主要为满足消费者多样性需求的地方。

为了种有效地回应这要求,制造业者确定他们的制造业拥有充分的柔性以满足他们迅速的生产发展的需要。

夹具设计,是指使用夹具在制造过程中装夹工件,以便他们能被加工成满足设计规格的产品,是提高制造业柔性一个重要的有利因素。

为了使有柔性的夹具成为可能,已经有相当程度的研究努力热衷于使用计算机辅助夹具设计(CAFD)工具和方法发展辅助夹具设计。

这篇文献包含这些研究努力的讨论。

超过七十五个CAFD 工具和方法在夹具设计方面被讨论并逐步实行计算机辅助和以其为基础的技术。

讨论的主要结论是当已经被在辅助夹具设计方面有重要的进步时,主要地有两个需要进一步的努力的研究议题。

第一,现在的CAFD 研究在本质上被分割,而且需要提供更多前后关联的夹具设计支持。

第二,更多聚焦于一个夹具的自身结构的详细设计。

2010 Elsevier 公司版权所有目录1. 介绍……………………………………………………………………………………………22. 夹具设计………………………………………………………………………………………23. 目前CAFD 的方法.......................................................................................4 3.1 设置规划.............................................................................................4 3.1.1 满足要求的设置规划 (4)3.2 夹具设计.............................................................................................4 3.2.1 达成定义夹具需求的方式...............................................................6 3.2.2 达成方法优化的布局规划...............................................................6 3.2.3 达成规划优化的方式 (6)3.3 元件设计…………………………………………………………………………………7 3.3.1 达成概念上的元件设计的方式…………………………………………………7 3.3.2 达成详细的元件设计的方式……………………………………………………7 3.4 确认………………………………………………………………………………………8 3.4.1 达成约束需求确认的方式………………………………………………………8 3.4.2达成公差需求确认的方式...............................................................8 3.4.3 达成碰撞检测需求确认的方式.........................................................8 3.4.4 达成可用性和供应的方式需求确认...................................................9 3.5 夹具数据的表现....................................................................................94. CAFD 研究的分析..........................................................................................9 4.1 CAFD 研究的被分割的性质 (9)4.2 有效地辅助元件设计...........................................................................10 4.3 综合地明确地叙述夹具需求 (10)4.4 确认CAFD 研究输出……………………………………………………………………105. 结论……………………………………………………………………………………………10 参考文献…………………………………………………………………………………………101. 介绍制造业企业的主要担心是发展设计和在短时间范围里生产多种高质量产品的能力。

中英文文献翻译-切削加工工序和夹具设计

中英文文献翻译-切削加工工序和夹具设计

英文原文Cutting process and fixture designMachine tools have evolved from the early foot-powered lathes of the Egyptians and John Wilkinson's boring mill. They are designed to provide rigid support for both the workpiece and the cutting tool and can precisely control their relative positions and the velocity of the tool with respect to the workpiece. Basically, in metal cutting, a sharpened wedge-shaped tool removes a rather narrow strip of metal from the surface of a ductile workpiece in the form of a severely deformed chip. The chip is a waste product that is 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.Most machining operations produce parts of differing geometry. If a rough cylindrical workpiece revolves about a central axis and the tool penetrates beneath its surface and travels parallel to the center of rotation, a surface of revolution is produced, and the operation is called turning. If a hollow tube is machined on the inside in a similar manner, the operation is called boring. Producing an external conical surface uniformly varying diameter is called taper turning, if the tool point travels in a path of varying radius, a contoured surface like that of a bowling pin can be produced; or, if the piece is short enough and the support is sufficiently rigid, a contoured surface could be produced by feeding a shaped tool normal to the axis of rotation. Short tapered or cylindrical surfaces could also be contour formed.Flat or plane surfaces are frequently required. They can be generated by radial turning or facing, in which the tool point moves normal to the axis of rotation. In other cases, it is more convenient to hold the workpiece steady and reciprocate the tool across it in a series of straight-line cuts with a crosswise feed increment before each cutting stroke. This operation is called planning and is carried out on a shaper. For larger pieces it is easier to keep the tool stationary and draw the workpiece under it as in planning. The tool is fed at each reciprocation. Contoured surfaces can be produced by using shaped tools.Multiple-edged tools can also be used. Drilling uses a twin-edged fluted tool for holes with depths up to 5 to 10 times the drill diameter. Whether thedrill turns or the workpiece rotates, relative motion between the cutting edge and the workpiece is the important factor. In milling operations a rotary cutter with a number of cutting edges engages the workpiece. Which moves slowly with respect to the cutter. Plane or contoured surfaces may be produced, depending on the geometry of the cutter and the type of feed. Horizontal or vertical axes of rotation may be used, and the feed of the workpiece may be in any of the three coordinate directions.Basic Machine ToolsMachine tools are used to produce a part of a specified geometrical shape and precise I size by removing metal from a ductile material in the form of chips. The latter are a waste product and vary from long continuous ribbons of a ductile material such as steel, which are undesirable from a disposal point of view, to easily handled well-broken chips resulting from cast iron. Machine tools perform five basic metal-removal processes: I turning, planning, drilling, milling, and grinding. All other metal-removal processes are modifications of these five basic processes. For example, boring is internal turning; reaming, tapping, and counter boring modify drilled holes and are related to drilling; bobbing and gear cutting are fundamentally milling operations; hack sawing and broaching are a form of planning and honing; lapping, super finishing. Polishing and buffing are variants of grinding or abrasive removal operations. Therefore, there are only four types of basic machine tools, which use cutting tools of specific controllable geometry: 1. lathes, 2. planers, 3. drilling machines, and 4. milling machines. The grinding process forms chips, but the geometry of the abrasive grain is uncontrollable.The amount and rate of material removed by the various machining processes may be I large, as in heavy turning operations, or extremely small, as in lapping or super finishing operations where only the high spots of a surface are removed.A machine tool performs three major functions: 1. it rigidly supports the workpiece or its holder and the cutting tool; 2. it provides relative motion between the workpiece and the cutting tool; 3. it provides a range of feeds and speeds usually ranging from 4 to 32 choices in each case.Speed and Feeds in MachiningSpeeds, feeds, and depth of cut are the three major variables for economical machining. Other variables are the work and tool materials, coolant and geometry of the cutting tool. The rate of metal removal and power required for machining depend upon these variables.The depth of cut, feed, and cutting speed are machine settings that must be established in any metal-cutting operation. They all affect the forces, the power, and the rate of metal removal. They can be defined by comparing them to the needle and record of a phonograph. The cutting speed (V) is represented by the velocity of- the record surface relative to the needle in the tone arm at any instant. Feed is represented by the advance of the needle radially inward per revolution, or is the difference in position between two adjacent grooves. The depth of cut is the penetration of the needle into the record or the depth of the grooves.Turning on Lathe CentersThe basic operations performed on an engine lathe are illustrated. Those operations performed on external surfaces with a single point cutting tool are called turning. Except for drilling, reaming, and lapping, the operations on internal surfaces are also performed by a single point cutting tool.All machining operations, including turning and boring, can be classified as roughing, finishing, or semi-finishing. The objective of a roughing operation is to remove the bulk of the material as rapidly and as efficiently as possible, while leaving a small amount of material on the work-piece for the finishing operation. Finishing operations are performed to obtain the final size, shape, and surface finish on the workpiece. Sometimes a semi-finishing operation will precede the finishing operation to leave a small predetermined and uniform amount of stock on the work-piece to be removed by the finishing operation.Generally, longer workpieces are turned while supported on one or two lathe centers. Cone shaped holes, called center holes, which fit the lathe centers are drilled in the ends of the workpiece-usually along the axis of the cylindrical part. The end of the workpiece adjacent to the tailstock is always supported by a tailstock center, while the end near the headstock may be supported by a headstock center or held in a chuck. The headstock end of the workpiece may be held in a four-jaw chuck, or in a type chuck. This method holds the workpiece firmly and transfers the power to the workpiece smoothly; the additional support to the workpiece provided by the chuck lessens the tendency for chatter to occur when cutting. Precise results can be obtained with this method if care is taken to hold the workpiece accurately in the chuck.Very precise results can be obtained by supporting the workpiece between two centers. A lathe dog is clamped to the workpiece; together they are driven by a driver plate mounted on the spindle nose. One end of the Workpiece is mecained;then the workpiece can be turned around in the lathe to machine the other end. The center holes in the workpiece serve as precise locating surfaces as well as bearing surfaces to carry the weight of the workpiece and to resist the cutting forces. After the workpiece has been removed from the lathe for any reason, the center holes will accurately align the workpiece back in the lathe or in another lathe, or in a cylindrical grinding machine. The workpiece must never be held at the headstock end by both a chuck and a lathe center. While at first thought this seems like a quick method of aligning the workpiece in the chuck, this must not be done because it is not possible to press evenly with the jaws against the workpiece while it is also supported by the center. The alignment provided by the center will not be maintained and the pressure of the jaws may damage the center hole, the lathe center, and perhaps even the lathe spindle. Compensating or floating jaw chucks used almost exclusively on high production work provide an exception to the statements made above. These chucks are really work drivers and cannot be used for the same purpose as ordinary three or four-jaw chucks.While very large diameter workpieces are sometimes mounted on two centers, they are preferably held at the headstock end by faceplate jaws to obtain the smooth power transmission; moreover, large lathe dogs that are adequate to transmit the power not generally available, although they can be made as a special. Faceplatejaws are like chuck jaws except that they are mounted on a faceplate, which has less overhang from the spindle bearings than a large chuck would have.I ntroduction of MachiningMachining as a shape-producing method is the most universally used and the most important of all manufacturing processes. Machining is a shape-producing process in which a power-driven device causes material to be removed in chip form. Most machining is done with equipment that supports both the work piece and cutting tool although in some cases portable equipment is used with unsupported workpiece.Low setup cost for small Quantities. Machining has two applications in manufacturing. For casting, forging, and press working, each specific shape to be produced, even one part, nearly always has a high tooling cost. The shapes that may he produced by welding depend to a large degree on the shapes of raw material that are available. By making use of generally high cost equipment but without special tooling, it is possible, by machining; to start with nearly any form of raw material, so tong as the exterior dimensions are great enough, and produce any desired shape from any material. Therefore .machining is usually the preferred method for producing one or a few parts, even when the design of the part would logically lead to casting, forging or press working if a high quantity were to be produced.Close accuracies, good finishes. The second application for machining is based on the high accuracies and surface finishes possible. Many of the parts machined in low quantities would be produced with lower but acceptable tolerances if produced in high quantities by some other process. On the other hand, many parts are given their general shapes by some high quantity deformation process and machined only on selected surfaces where high accuracies are needed. Internal threads, for example, are seldom produced by any means other than machining and small holes in press worked parts may be machined following the press working operations.Primary Cutting ParametersThe basic tool-work relationship in cutting is adequately described by means of four factors: tool geometry, cutting speed, feed, and depth of cut.The cutting tool must be made of an appropriate material; it must be strong, tough, hard, and wear resistant. The tool s geometry characterized by planes and angles, must be correct for each cutting operation. Cutting speed is the rate at which the work surface passes by the cutting edge. It may be expressed in feet per minute.For efficient machining the cutting speed must be of a magnitude appropriate to the particular work-tool combination. In general, the harder the work material, the slower the speed.Feed is the rate at which the cutting tool advances into the workpiece. "Where the workpiece or the tool rotates, feed is measured in inches per revolution. When the tool or the work reciprocates, feed is measured in inches per stroke, Generally, feed varies inversely with cutting speed for otherwise similar conditions.The depth of cut, measured inches is the distance the tool is set into the work. It is the width of the chip in turning or the thickness of the chip in a rectilinear cut. In roughing operations, the depth of cut can be larger than for finishing operations.The Effect of Changes in Cutting Parameters on Cutting TemperaturesIn metal cutting operations heat is generated in the primary and secondary deformation zones and these results in a complex temperature distribution throughout the tool, workpiece and chip. A typical set of isotherms is shown in figure where it can be seen that, as could be expected, there is a very large temperature gradient throughout the width of the chip as the workpiece material is sheared in primary deformation and there is a further large temperature in the chip adjacent to the face as the chip is sheared in secondary deformation. This leads to a maximum cutting temperature a short distance up the face from the cutting edge and a small distance into the chip.Since virtually all the work done in metal cutting is converted into heat, it could be expected that factors which increase the power consumed per unit volume of metal removed will increase the cutting temperature. Thus an increase in the rake angle, all other parameters remaining constant, will reduce the power per unit volume of metal removed and the cutting temperatures will reduce. When considering increase in unreformed chip thickness and cutting speed the situation is more complex. An increase in undeformed chip thicknesstends to be a scale effect where the amounts of heat which pass to the workpiece, the tool and chip remain in fixed proportions and the changes in cutting temperature tend to be small. Increase in cutting speed; however, reduce the amount of heat which passes into the workpiece and this increase the temperature rise of the chip m primary deformation. Further, the secondary deformation zone tends to be smaller and this has the effect of increasing the temperatures in this zone. Other changes in cutting parameters have virtually no effect on the power consumed per unit volume of metal removed and consequently have virtually no effect on the cutting temperatures. Since it has been shown that even small changes in cutting temperature have a significant effect on tool wear rate it is appropriate to indicate how cutting temperatures can be assessed from cutting data.The most direct and accurate method for measuring temperatures in high -speed-steel cutting tools is that of Wright &. Trent which also yields detailed information on temperature distributions in high-speed-steel cutting tools. The technique is based on the metallographic examination of sectioned high-speed-steel tools which relates microstructure changes to thermal history.Trent has described measurements of cutting temperatures and temperature distributions for high-speed-steel tools when machining a wide range of workpiece materials. This technique has been further developed by using scanning electron microscopy to study fine-scale microstructure changes arising from over tempering of the tempered martens tic matrix of various high-speed-steels. This technique has also been used to study temperature distributions in both high-speed -steel single point turning tools and twist drills.Wears of Cutting ToolDiscounting brittle fracture and edge chipping, which have already been dealt with, tool wear is basically of three types. Flank wear, crater wear, and notch wear. Flank wear occurs on both the major and the minor cutting edges. On the major cutting edge, which is responsible for bulk metal removal, these results in increased cutting forces and higher temperatures which if left unchecked can lead to vibration of the tool and workpiece and a condition where efficient cutting can no longer take place. On the minor cutting edge, which determines workpiece size and surface finish, flank wear can result in an over sized product which has poor surface finish. Under most practical cutting conditions, the tool will fail due to major flank wear before the minor flank wear is sufficiently large to result in the manufacture of an unacceptable component.Because of the stress distribution on the tool face, the frictional stress in the region of sliding contact between the chip and the face is at a maximum at the start of the sliding contact region and is zero at the end. Thus abrasive wear takes place in this region with more wear taking place adjacent to the seizure region than adjacent to the point at which the chip loses contact with the face. This result in localized pitting of the tool face some distance up the face which is usually referred to as catering and which normally has a section in the form of a circular arc. In many respects and for practical cutting conditions, crater wear is a less severe form of wear than flank wear and consequently flank wear is a more common tool failure criterion. However, since various authors have shown that the temperature on the face increases more rapidly with increasing cutting speed than the temperature on the flank, and since the rate of wear of any type is significantly affected by changes in temperature, crater wear usually occurs at high cutting speeds.At the end of the major flank wear land where the tool is in contact with the uncut workpiece surface it is common for the flank wear to be more pronounced than along the rest of the wear land. This is because of localised effects such as a hardened layer on the uncut surface caused by work hardening introduced by a previous cut, an oxide scale, and localised high temperatures resulting from the edge effect. This localised wear is usually referred to as notch wear and occasionally is very severe. Although the presence of the notch will not significantly affect the cutting properties of the tool, the notch is often relatively deep and if cutting were to continue there would be a good chance that the tool would fracture.If any form of progressive wear allowed to continue, dramatically and the tool would fail catastrophically, i. e. the tool would be no longer capable of cutting and, at best, the workpiece would be scrapped whilst, at worst, damage could be caused to the machine tool. For carbide cutting tools and for all types of wear, the tool is said to have reached the end of its useful life long before the onset of catastrophic failure. For high-speed-steel cutting tools, however, where the wear tends to be non-uniform it has been found that the most meaningful and reproducible results can be obtained when the wear is allowed to continue to the onset ofcatastrophic failure even though, of course, in practice a cutting time far less than that to failure would be used. The onset of catastrophic failure is characterized by one of several phenomena, the most common being a sudden increase in cutting force, the presence of burnished rings on the workpiece, and a significant increase in the noise level.Mechanism of Surface Finish ProductionThere are basically five mechanisms which contribute to the production of a surface which have been machined. These are:(l) The basic geometry of the cutting process. In, for example, single point turning the tool will advance a constant distance axially per revolution of the work price and the resultant surface will have on it, when viewed perpendicularly to the direction of tool feed motion, a series of cusps which will have a basic form which replicates the shape of the tool in cut.(2) The efficiency of the cutting operation. It has already been mentioned that cutting with unstable built-up-edges will produce a surface which contains hard built-up-edge fragments which will result in a degradation of the surface finish. It can also be demonstrated that cutting under adverse conditions such as apply when using large feeds small rake angles and low cutting speeds, besides producing conditions which lead to unstable built-up-edge production, the cutting process itself can become unstable and instead of continuous shear occurring in the shear zone, tearing takes place, discontinuous chips of uneven thickness are produced, and the resultant surface is poor. This situation is particularly noticeable when machining very ductile materials such as copper and aluminum.(3) The stability of the machine tool. Under some combinations of cutting conditions; workpiece size, method of clamping ,and cutting tool rigidity relative to the machine tool structure, instability can be set up in the tool which causes it to vibrate. Under some conditions this vibration will reach and maintain steady amplitude whilst under other conditions the vibration will built up and unless cutting is stopped considerable damage to both the cutting tool and workpiece may occur. This phenomenon is known as chatter and in axial turning is characterized by long pitch helical bands on the workpiece surface and short pitch undulations on the transient machined surface.(4)The effectiveness of removing swarf. In discontinuous chip production machining, such as milling or turning of brittle materials, it is expected that the chip (swarf) will leave the cutting zone either under gravity or with the assistance of a jet of cutting fluid and that they will not influence the cut surface in any way. However, when continuous chip production is evident, unless steps are taken to control the swarf it is likely that it will impinge on the cut surface and mark it. Inevitably, this marking besides looking.(5)The effective clearance angle on the cutting tool. For certain geometries of minor cutting edge relief and clearance angles it is possible to cut on the major cutting edge and burnish on the minor cutting edge. This can produce a good surface finish but, of course, it is strictly a combination of metal cutting and metal forming and is not to be recommended as a practical cutting method. However, due to cutting tool wear, these conditions occasionally arise and lead to a marked change in the surface characteristics.Limits and TolerancesMachine parts are manufactured so they are interchangeable. In other words, each part of a machine or mechanism is made to a certain size and shape so will fit into any other machine or mechanism of the same type. To make the part interchangeable, each individual part must be made to a size that will fit the mating part in the correct way. It is not only impossible, but also impractical to make many parts to an exact size. This is because machines are not perfect, and the tools become worn. A slight variation from the exact size is always allowed. The amount of this variation depends on the kind of part being manufactured. For examples part might be made 6 in. long with a variation allowed of 0.003 (three-thousandths) in. above and below this size. Therefore, the part could be 5.997 to 6.003 in. and still be the correct size. These are known as the limits. The difference between upper and lower limits is called the tolerance.A tolerance is the total permissible variation in the size of a part.The basic size is that size from which limits of size arc derived by the application of allowances and tolerances.Sometimes the limit is allowed in only one direction. This is known as unilateral tolerance.Unilateral to learning is a system of dimensioning where the tolerance (that is variation) is shown in only one direction from the nominal size. Unilateral to learning allow the changing of tolerance on a hole or shaft without seriously affecting the fit.When the tolerance is in both directions from the basic size it is known as a bilateral tolerance (plus and minus).Bilateral to learning is a system of dimensioning where the tolerance (that is variation) is split and is shown on either side of the nominal size. Limit dimensioning is a system of dimensioning where only the maximum and minimum dimensions arc shown. Thus, the tolerance is the difference between these two dimensions.Surface Finishing and Dimensional ControlProducts that have been completed to their proper shape and size frequently require some type of surface finishing to enable them to satisfactorily fulfill their function. In some cases, it is necessary to improve the physical properties of the surface material for resistance to penetration or abrasion. In many manufacturing processes, the product surface is left with dirt .chips, grease, or other harmful material upon it. Assemblies that are made of different materials, or from the same materials processed in different manners, may require some special surface treatment to provide uniformity of appearance.Surface finishing may sometimes become an intermediate step processing. For instance, cleaning and polishing are usually essential before any kind of plating process. Some of the cleaning procedures are also used for improving surface smoothness on mating parts and for removing burrs and sharp corners, which might be harmful in later use. Another important need for surface finishing is for corrosion protection in a variety of: environments. The type of protection procedure will depend largely upon the anticipated exposure, with due consideration to the material being protected and the economic factors involved.Satisfying the above objectives necessitates the use of main surface-finishing methods that involve chemical change of the surface mechanical work affecting surface properties, cleaning by a variety of methods, and the application of protective coatings, organic and metallic.In the early days of engineering, the mating of parts was achieved by machining one part as nearly as possible to the required size, machining the mating part nearly to size, and then completing its machining, continually offering the other part to it, until the desired relationship was obtained. If it was inconvenient to offer one part to the other part during machining, the final work was done at the bench by a fitter, who scraped the mating parts until the desired fit was obtained, the fitter therefore being a 'fitter' in the literal sense. J It is obvious that the two parts would have to remain together, and m the event of one having to be replaced, the fitting would have to be done all over again. In these days, we expect to be able to purchase a replacement for a broken part, and for it to function correctly without the need for scraping and other fitting operations.When one part can be used 'off the shelf' to replace another of the same dimension and material specification, the parts are said to be interchangeable. A system of interchangeability usually lowers the production costs as there is no need for an expensive, 'fiddling' operation, and it benefits the customer in the event of the need to replace worn parts.Automatic Fixture DesignTraditional synchronous grippers for assembly equipment move parts to the gripper center-line, assuring that the parts will be in a known position after they arc picked from a conveyor or nest. However, in some applications, forcing the part to the center-line may damage cither the part or equipment. When the part is delicate and a small collision can result in scrap, when its location is fixed by a machine spindle , or when tolerances are tight, it is preferable to make a gripper comply with the position of the part, rather than the other way around. For these tasks, zaytran Inc. Of Elyria, Ohio, has created the GPN series of non- synchronous, compliant grippers. Because the force and synchronizations systems of the grippers are independent, the synchronization system can be replaced by a precision slide system without affecting gripper force. Gripper sizes range from 51b gripping force and 0.2 in. stroke to 40Glb gripping force and 6in stroke. Grippers。

汽车焊接夹具设计外文文献翻译

汽车焊接夹具设计外文文献翻译

汽车焊接夹具设计外文文献翻译汽车焊接夹具设计外文文献翻译(含:英文原文及中文译文)文献出处:Semjon Kim.Design of Automotive Welding Fixtures [J]. Computer-Aided Design, 2013, 3(12):21-32.英文原文Design of Automotive Welding FixturesSemjon Kim1 AbstractAccording to the design theory of car body welding fixture, the welding fixture and welding bus of each station are planned and designed. Then the fixture is modeled and assembled. The number and model of the fixture are determined and the accessibility is judged. Designed to meet the requirements of the welding fixture.Keywords: welded parts; foundation; clamping; position1 IntroductionAssembly and welding fixtures are closely related to the production of high-quality automotive equipment in automotive body assembly and welding lines. Welded fixtures are an important part of the welding process. Assembly and welding fixtures are not only the way to complete the assembly of parts in this process, but also as a test and calibration procedure on the production line to complete the task of testing welding accessories and welding quality. Therefore, the design and manufacture ofwelding fixtures directly affect the production capacity and product quality of the automobile in the welding process. Automotive welding fixtures are an important means of ensuringtheir manufacturing quality and shortening their manufacturing cycle. Therefore, it is indispensable to correctly understand the key points of welding fixture design, improve and increase the design means and design level of welding fixtures, and improve the adjustment and verification level of fixtures. It is also an auto manufacturing company in the fierce competition. The problem that must be solved to survive.The style of the car is different from that of the car. Therefore, the shape of the welding jig is very different. However, the design, manufacture, and adjustment are common and can be used for reference.2. Structural design of welding fixtureThe structure design of the welding fixture ensures that the clip has good operational convenience and reliable positioning of the fixture. Manufacturers of welding fixtures can also easily integrate adjustments to ensure that the surfaces of the various parts of the structure should allow enough room for adjustments to ensure three-dimensional adjustment. Of course, under the premise of ensuring the accuracy of the welding jig, the structure of the welding jig should be as simple as possible. The fixture design is usually the position of all components on the fixture is determined directly based on the design basis, and ultimately ensure thatthe qualified welding fixture structure is manufactured. According to the working height, the height of the fixture bottom plate can be preliminarily determined, that is, the height of the fixture fixing position. The welding fixture design must first consider the clamping method. There are two types, manual and pneumatic. Manual clamping is generally suitable for small parts, external parts, and small batches of workpieces. For large bodyparts, planning in the production line, automation High-demand welding fixtures should be pneumatically clamped. Automobile production is generally pneumatically clamped, and manual mass clamping can be used as auxiliary clamping. This can reduce costs accordingly. Some manual clamping products already have standard models and quantities, which can be purchased in the market when needed. For some devices, pneumatic clamping is specified, but if pneumatic clamping is used, the workpiece may be damaged. Therefore, it is possible to manually press the place first to provide a pneumatic clamping force to clamp the workpiece. This is manual-pneumatic. . The fixture clamping system is mounted on a large platform, all of which are fixed in this welding position to ensure that the welding conditions should meet the design dimensions of the workpiece coordinate system positioning fixture, which involves the benchmark.3. Benchmarks of assembly and welding fixtures and their chosen support surfaces3.1 Determination of design basisIn order to ensure that the three-dimensional coordinates of the automatic weldment system are consistent, all welding fixtures must have a common reference in the system. The benchmark is the fixture mounting platform. This is the X, Y coordinate, each specific component is fixed at the corresponding position on the platform, and has a corresponding height. Therefore, the Z coordinate should be coordinated, and a three-dimensional XYZ coordinate system is established. In order to facilitate the installation and measurement of the fixture, the mounting platform must have coordinates for reference. There are usually three types. The structure is as follows:3.1.1 Reference hole methodThere are four reference holes in the design of the installation platform, in which the two directions of the center coordinates of each hole and the coordinates of the four holes constitute two mutually perpendicular lines. This is the collection on the XY plane coordinate system. The establishment of this benchmark is relatively simple and easy to process, but the measurements and benchmarks used at the same time are accurate. Any shape is composed of spatial points. All geometric measurements can be attributed to measurements of spatial points. Accurate spatial coordinate acquisition is therefore the basis for assessing any geometric shape. Reference A coordinated direction formed by oneside near two datums.3.1.2 v-type detection methodIn this method, the mounting platform is divided into two 90-degree ranges. The lines of the two axes make up a plane-mounted platform. The plane is perpendicular to the platform. The surface forms of these two axis grooves XY plane coordinate system.3.1.3 Reference block methodReference Using the side block perpendicular to the 3D XYZ coordinate system, the base of a gage and 3 to 4 blocks can be mounted directly on the platform, or a bearing fixing fixture platform can be added, but the height of the reference plane must be used to control the height , must ensure the same direction. When manufacturing, it is more difficult to adjust the previous two methods of the block, but this kind of measurement is extremely convenient, especially using the CMM measurement. This method requires a relatively low surface mount platform forthe reference block, so a larger sized mounting platform should use this method.Each fixture must have a fixed coordinate system. In this coordinate system, its supporting base coordinate dimensions should support the workpiece and the coordinates correspond to the same size. So the choice of bearing surface in the whole welding fixture system 3.2When the bearing surface is selected, the angle between the tangentplane and the mounting platform on the fixed surface of the welding test piece shall not be greater than 15 degrees. The inspection surface should be the same as the welded pipe fittings as much as possible for the convenience of flat surface treatment and adjustment. The surface structure of the bearing should be designed so that the module can be easily handled, and this number can be used for the numerical control of the bearing surface of the product. Of course, designing the vehicle body coordinate point is not necessarily suitable for the bearing surface, especially the NC fixture. This requires the support of the fixture to block the access point S, based on which the digital surface is established. This surface should be consistent with the supported surface. So at this time, it is easier and easier to manufacture the base point S, CNC machining, precision machining and assembly and debugging.3.2 Basic requirements for welding fixtureIn the process of automobile assembly and production, there are certain requirements for the fixture. First, according to the design of the automobile and the requirements of the welding process, the shape, size and precision of the fixture have reached the design requirements and technical requirements. This is a linkthat can not be ignored, and the first consideration in the design of welding fixture is considered. When assembling, the parts or parts of the assembly should be consistent with the position of the design drawings of the car and tighten with the fixture.At the same time, the position should be adjusted to ensure that the position of the assembly parts is clamped accurately so as to avoid the deformation or movement of the parts during the welding. Therefore, this puts forward higher requirements for welding jig. In order to ensure the smooth process of automobile welding and improve the production efficiency and economic benefit, the workers operate conveniently, reduce the strength of the welder's work, ensure the precision of the automobile assembly and improve the quality of the automobile production. Therefore, when the fixture design is designed, the design structure should be relatively simple, it has good operability, it is relatively easy to make and maintain, and the replacement of fixture parts is more convenient when the fixture parts are damaged, and the cost is relatively economical and reasonable. But the welding fixture must meet the construction technology requirements. When the fixture is welded, the structure of the fixture should be open so that the welding equipment is easy to close to the working position, which reduces the labor intensity of the workers and improves the production efficiency.4. Position the workpieceThe general position of the workpiece surface features is determined relative to the hole or the apparent positioning reference surface. It is commonly used as a locating pin assembly. It is divided into two parts: clamping positioning and fixed positioning. Taking into account thewelding position and all welding equipment, it is not possibleto influence the removal of the final weld, but also to allow the welding clamp or torch to reach the welding position. For truly influential positioning pins and the like, consider using movable positioning pins. In order to facilitate the entry and exit of parts, telescopic positioning pins are available. The specific structure can be found in the manual. The installation of welding fixtures should be convenient for construction, and there should be enough space for assembly and welding. It must not affect the welding operation and the welder's observation, and it does not hinder the loading and unloading of the weldment. All positioning elements and clamping mechanisms should be kept at a proper distance from the solder joints or be placed under or on the surface of the weldment. The actuator of the clamping mechanism should be able to flex or index. According to the formation principle, the workpiece is clamped and positioned. Then open the fixture to remove the workpiece. Make sure the fixture does not interfere with opening and closing. In order to reduce the auxiliary time for loading and unloading workpieces, the clamping device should use high-efficiency and quick devices and multi-point linkage mechanisms. For thin-plate stampings, the point of application of the clamping force should act on the bearing surface. Only parts that are very rigid can be allowed to act in the plane formed by several bearing points so that the clamping force does not bend the workpiece or deviate from the positioning reference. In addition, it must be designed so that it does not pinch the hand when the clamping mechanism is clamped to open.5. Work station mobilization of welding partsMost automotive solder fittings are soldered to complete in several processes. Therefore, it needs a transmission device.Usually the workpiece should avoid the interference of the welding fixture before transmission. The first step is to lift the workpiece. This requires the use of an elevator, a crane, a rack and pinion, etc. The racks and gears at this time Structure, their structural processing, connection is not as simple as the completion of the structure of the transmission between the usual connection structure of the station, there are several forms, such as gears, rack drive mechanism, transmission mechanism, rocker mechanism, due to the reciprocating motion, shake The transfer of the arm mechanism to the commissioning is better than the other one, so the common rocker arm transfer mechanism is generally used.6 ConclusionIn recent years, how to correctly and reasonably set the auxiliary positioning support for automotive welding fixtures is an extremely complicated system problem. Although we have accumulated some experience in this area, there is still much to be learned in this field. Learn and research to provide new theoretical support for continuous development and innovation in the field of welding fixture design. Withthe development of the Chinese automotive industry, more and more welding fixtures are needed. Although the principle of the fixture is very simple, the real design and manufacture of a high-quality welding fixture system is an extremely complicated project.中文译文汽车焊接夹具的设计Semjon Kim1摘要依据车体焊装线夹具设计理论, 对各工位焊接夹具及其焊装总线进行规划、设计, 之后进行夹具建模、装配, 插入焊钳确定其数量、型号及判断其可达性,最终设计出符合要求的焊接夹具。

外文翻译--传动轴凸缘叉夹具的设计

外文翻译--传动轴凸缘叉夹具的设计

外文翻译--传动轴凸缘叉夹具的设计黑龙江工程学院本科生毕业设计附录Fork Shaft Lugs fixture designShell group processing according to the results of the machine andthe group chosen type design group clamps, group clamps Realize that the group process, favorable to reasonable design, if no group clamps or design group clamps, convenient adjustment group processing can realize smoothly.The machine tool's fixture priority is to ensure machining accuracy, especially that of the machining process and positioning surface and processed surface between the position precision. After using thisfixture mainly rely on precision tools and fixtures to ensure no longer rely on workers, the technical level. Second is to improve labor productivity, reduce cost, use fixture after is crossed, can reduce the auxiliary time, and easy to implement and multistage process. In modern times, is widely used in the machine tool's fixture etc mobile pneumatic, hydraulic clamping device, can make the assistant time do step.In the group technology group clamps are under the guidance of the principle, process and design for the implementation of the group, and special fixture Compared with the design group clamps, not for a certain parts of a process, but a group of some parts, Which group clamps to adapt to all parts of the group parts in a process of processing.Design of the key and difficult.When the workpiece in machine processing, the first to make workpiece in machine or a fixture in the correct position, it is the location, to prevent the process of cutting force or other forces destroyed the correct position, still must be fastened clamping workpiece, this is the clamping workpiece position and clamping workpiece installation process is called. Due to the workpiece position and orientation error, error called for clamping deformation and the error is called clamping error. Positioning error and clamping workpiece installation error named error.Because of this all parts for 21 kinds of workpieces, so the scheme is key to determine the fixture clamping deformation control at will The smallest. While clamping deformation control cannot rely on operators to realize in the past shell parts and machining by small and reliable clamping force to reduce clamping deformation, this will inevitably produce adverse product. In the introduction of domestic product technology at the same time, don't notice the processing technology, especially the shell parts, production batch processing, different, use equipment that needs are different, clamping orientated in the introduction,1黑龙江工程学院本科生毕业设计digestion and absorption and must therefore in the design process, according to the actual needs of clamping positioning in blank, add uniform positioning and clamping point.The selection principle of orientated may not deviate from the principle of localization, but at the time must note in the selection, I truly, Planar 3 point must form a stable support, namely the gravity of the triangle, near the workpiece center turn against restrictions freedom 2 some farther, the more accurate positioning.In parts of the shell, the key process is first step - graphic processing. According to the production batch and parts The structureand the precision, some parts processing, some parts of planar alone on a plane and hole machining process. Graphic processing quality directly cause the whole process, the success or failure. Surface processing, mainly is bad, the flatness of the flatness of the next procedure of processing produce larger clamping deformation, clamping, precisionparts in tolerance, loosen, clamping displacementrestoring, precision parts will change, and with regularity. Surface processing by fixture causes adverse has two main: 1, the location selection is not reasonable, 2, clamping point is not reasonable. Therefore, the shell parts processing, surface of fixture design becomes important.In the traditional processing, for milling machining processes,plane commonly, add a few auxiliary support to prevent due to the distortion caused by cutting force influence, because high-speed cuttingmachining precision cutting force, so, no need additional support commonly.In the face of processing, must consider the process of flexibility, can use the car is not to milling machining. In clamping point, on the choice of pay attention to the following problems:1. By 3 strong point to form a support to support workpiece surface, can avoid blank piece of planar degree due to the deviation caused the machined surface flatness, and supporting and clamping point should avoid a moment, and led up distortion. Because of clamping workpiece elastic deformation, loosen the clamping after springback, can cause planar degree, it is super flatness of the main reason.2. The best point and clamping point is the sphere, ensure all, otherwise, it will point is because the plane deformation caused by torsion blank clamping deformation. The deformation will also cause planar degree.3. When the workpiece surface cannot clamping, can use flank clamping, if clamping parts is deduced.and, must increase in the block, to avoid clamping deformation. The clamping way, had better not use or using other techniques, or request processing plane designers in clamping point increase in design.4. Because of the high-speed machining cutting force and deformation of more than 30% reduction processing, generally recommend that don't add additional support can guarantee machining accuracy.5. 2 limit rotational degree of freedom, the distance as far as possible, orientated if blank has note hole, 2 (note hole taper pin location using elastic is the most simple positioning scheme.2黑龙江工程学院本科生毕业设计In the design of the group clamps, considering the problems at the same time, we also need to consider many parts adopt a fixture, and replacing time processing varieties in a short time to finish. So the fixture design must consider quick change. This fixture is typical ofsix principles of fixture, positioning clamping adopt pneumatic clamping screw. This fixture locating adopts point positioning forms, interface, nearly may also used clamping point, ensure orientated and clamping point in the same line, this fixture milling face results in the plane degrees below, the precision of 0.02 from the Angle of subsequent processing position from the Angle of use or can be very well meet the requirements.In addition, in parts processing process, for a process, whether to use fixture, use what type of clip What class, and the use of fixture in jig design must be carefully considered before. Besides the machining quality assurance from view, should also do economic analysis to ensure that the design of fixture in the economy.传动轴凸缘叉夹具的设计凸缘叉成组加工要根据分组结果及选定的机床型号进行成组夹具设计,成组夹具是实现成组加工的有利保证,分组再合理,如果设计不出成组夹具或设计的成组夹具调整不方便,成组加工也不能顺利实现。

机械制造专业外文翻译--机床夹具的分类与构成

机械制造专业外文翻译--机床夹具的分类与构成

外文原文:Machine classification and pose fixture1 fixture in the role of machiningWorkpiece clamping fixture is a kind of process equipment, it is widely used in mechanical machining of the manufacturing process, heat treatment, assembly, welding and testing processes. In the use of metal-cutting machine tools collectively referred to as the jig fixture. n a modern production machine is an indispensable fixture of the process equipment, machining of the workpiece, the processing requirements in order to ensure. First of all to the workpiece and the machine tool relative to a correct position, and this location during processing does not change the impact of external forces. To this end, during the pre-machining, workpiece clamping must be good. There are two ways to clamp workpiece: one is directly clamping the workpiece in the machine table or on the chuck; The other is the workpiece in the fixture on the fixture. The first method used when the workpiece clamping, the general design requirements have to press lines in the surface to draw the size and location, clamping, or when the needle is zoned dial indicator to find is after the clamping. This method need special equipment, but low efficiency, are generally used for one-piece and small batch production. Large quantities, mostly with the workpiece clamping fixture. With the merits of the workpiece clamping fixtures are as follows: (l) Guarantee the stability of the machining accuracy of workpiece. Workpieces with clamping fixture, the workpiece relative to the location of tool and machine tool to ensure the accuracy of the fixture from the technical level of workers, so that a number of workpiece machining accuracy of the line.(2) To improve labor productivity. Workpiece clamping fixture can facilitate the user easily、rapidly, and the workpiece does not need to find is crossed, can significantly reduce the supplementary working hours, to improve labor productivity; workpiece in the fixture after the fixture to improve the rigidity of the workpiece, thus cutting the amount of increase, to improve labor productivity; can use more pieces of multi-workpiece clamping fixture, and the use of efficient clamping bodies, to further improve labor productivity.(3) To expand the use of machine tools. Machine tools in general use a dedicated machine tool fixture can expand the scope of the process and give full play to the potential of machine tools to achieve a multi-machine use. For example, the use of adedicated fixture can be easily Lathe processing small box to the workpiece. Even in the lathe out of oil, a reduction of expensive dedicated machines, reducing the cost, which is particularly important for small and medium-sized factories.(4) To improve the operator's working conditions. As the pneumatic, hydraulic, electro-magnetic power source, such as the application in the fixture, on the one hand to reduce the labor intensity of workers; the other hand, it guarantees the reliability of the workpiece clamping, and to achieve the interlocking machine, to avoid accidents, ensure the operator safety and machine tool equipment(5) To reduce costs. In mass production after the use of fixture, from stem to increase labor productivity, lower level technical workers, as well as lower scrap and other reasons, obviously to reduce the production costs.Fixture manufacturing cost-sharing in a group of workpieces, each workpiece to increase the cost is very minimal, far less than as a result of increased labor productivity and reduce costs. The greater volume of workpiece, fixture made to use has become more significant economic benefits.2 Fixture Category2.1 General characteristics of the fixture by CategoryAccording to the production in different types of fixtures in the common characteristics of machine tool fixture fixture can be divided into general, special fixtures, adjustable clamp, and automatic line of modular fixture fixture, such as: (l) General Fixture. Universal fixture refers to the structure, size has been standardized, and has a certain universal fixture. This type of fixture adaptable, can be used to setup the scope of a certain shape and size of various parts.(2)A dedicated fixture. This type of fixture is designed for a particular part of the processing procedures and the design and manufacture. Relatively stable in the product, the production of larger quantities, used a variety of special fixtures, access to higher productivity and machining accuracy. (3) Adjustable fixture. Adjustable fixture for general fixture and special fixture and the defects developed a new kind of fixture. Of different types and sizes of the workpiece, simply adjust or replace the fixture at the original location of the individual components and will be used to clamp components. (4) Modular Fixture. Modular fixture is a modular fixture. Standard components of the module with high precision and resistance to abrasion, can be assembled into a variety of fixtures. Removable fixture used to clean the assembly after the new fixture left. (5) Automatic line fixture. Automatic line clamp generally divided into two categories:fixed-type fixture, which is similar to a dedicated fixture; other accompanying a fixture for the use of the workpiece in the fixture, together with the movement, and automatic workpiece along the line from a move to the next position position for processing.2.2 Classification by the use of machine tools ClassificationBy the use of machine tools can be divided into lathe jig fixtures, milling fixtures, drilling fixtures, hang-bed fixture, jig gear machine, CNC machine tool fixture, automatic machine tool fixtures, accompanied by automatic line, and other fixtures, such as machine tools. This is a special fixture design of the classification method used. Dedicated fixture design, the machine group, the type and the main parameters have been determined. Their difference is the cutting forming machine tool movements, so the connection fixture with the machine in different ways. Machining accuracy of their different requirements.2.3 Clamping fixture according to the power sourceClamping fixture according to the power source can be divided into manual fixture, pneumatic fixtures, hydraulic fixtures, gas fixtures by force, electromagnetic fixture, vacuum fixtures, fixture, such as centrifugal force.3 the composition of fixtureAlthough the structure of machine tool fixture range, but their components can be summarized as the following sections.(1) Positioning components. Typically, when the shape of the workpiece datum position established, the position will be the basic components of the structure identified(2) Clamping device. Positioning of the workpiece in the fixture, the need to clamp the workpiece before processing to ensure that the workpiece during processing is not due to external force and undermine its position.(3) The specific folder. Fixture and the skeleton matrix, all the components through the fixture it will constitute a whole.(4) Of the knife or the guide. Tool used to determine position relative to the correct position of components. Of the knife device common in milling fixture. Used to adjust the cutter knife block position before machining.(5) To connect components. Connected components in the machine tool fixture is todetermine the correct position on the component, therefore, can double as a specific folder to connect components. Lathe fixture on the transition plate, the positioning ofmilling machine fixture on key components are connected.(6) Other devices or components. According to the processing needs, some degree fixture device were used by mode device, the whole device, and the balance of the top block and so on. These components or devices specially designed need.中文译文:机床夹具的分类与构成1机床夹具在机械加工中的作用夹具是一种装夹工件的工艺装备,它广泛地应用于机械制造过程的切削加工、热处理、装配、焊接和检测等工艺过程中。

第四章夹具设计

第四章夹具设计
2.基准移位误差ΔY 由于定位副的制造公差和最小配合间隙的影响,使得 定位基准和限位基准不重合,导致各个工件不一致,从而 给加工尺寸造成误差,这个误差称为基准位移误差。
3.定位误差的计算方法 在计算定位误差时,要注意误差的方向和工序 尺寸的方向。当基准位移误差和基准不重合误差与 工序尺寸的方向相同或平行时,则定位误差为两项 误差的代数和;若方向不同,则应将各误差向工序 尺寸方向投影,然后求其代数和。
第四章 夹具设计
Clamping Apparatus Design
第一节 概述 一、夹具的定义 在机械生产中,用来安装工件使之固定在正确位置上 所使用的工艺装备统称为夹具。 在机械加工中,为了迅速、准确地确定工件在机床上 的位置,保证工件与机床、刀具的正确相对位置关系,并 在加工过程中始终保持这个正确位置所使用的工艺装备称 为夹具。 General Consideration
六、欠定位与过定位
欠定位:按工序的加工要求,应该被限制的自由度而没有 被限制的定位,称为欠定位。欠定位是不允许的。
过定位:在夹具中,若某一自由度被定位元件重复限制, 这种定位称为过定位。
消除过定位的两种措施
(1)提高定位基面之间以及定位元件定位表面之间的位 置精度,以减少或消除过定位引起的干涉。
三、工件以外圆柱面定位 1.在V形块中定位
特点
对中性好,既能使工件的定位基面轴线对中在 V形块两斜面的对称平面上,而不受定位基面直径 误差的影响,并且安装方便。
V形块两斜面夹角一般为60、90、120,其中90V形 块的典型结构和尺寸已标准化,设计时可参考有关手册。
2.在定位套中定位
定位套其内孔轴线是限位基准,内孔面是限位基面。 为了限制工件轴向自由度,常与端面联合定位。定位套结 构简单,容易制造,但定心精度不高,只适用于精基面。 半圆套下半圆套为定位元件,上半圆套起夹紧作用。 主要用于大型轴类零件及不便于轴向装卸的零件。定位基 面的精度不低于IT8-IT9,半圆套的最小直径应取工件定 位基面的最大直径。

外文翻译-夹具设计机械

外文翻译-夹具设计机械

外文翻译基于事例推理的夹具设计研究与应用摘要:根据基于事例的设计方法,提出采用工序件的特征信息和夹具的结构特征信息来描述夹具的相似性,并建立了包括这2方面主要特征信息为基础的事例索引码,设计了事例库的结构形式,创建了层次化的事例组织方式;同时,提出了基于知识引导的夹具事例检索算法,以及事例的修改和采用同族事例码进行相似事例的存贮,形成了基于事例推理的夹具设计.所开发的原型系统在型号工程夹具设计等项目的设计过程中得到了应用,并取得了令人满意的使用效果.关键词: 基于事例的推理夹具设计CAD夹具是以确定工件安全定位准确为目的的装置,并在加工过程中保持工件与刀具或机床的位置一致不变。

因为夹具的结构依赖于产品的特点和在企业规划中加工工序的地位,所以它的设计是制造过程中的瓶颈,制约着效率的提高. 夹具设计是一个复杂的过程,需要有从大量的设计论文中了解质量知识的经验,这些设计论文包括工件的结构设计、涉及加工工艺,和加工环境。

当用这些擅长绘制详细设计图的传统的CAD工具(如Unigraphics、CATIA、Pro/E)时,这仍然是一项非常耗时的工作,但是利用以往的设计经验和资源也不能提供一些益处,而这正是提高效率的关键因素. 基于事例推理(CBR) 的方法适应以往个案解决的办法,建立一个新问题的方法,主要有以下四步骤:检索、利用、修改,并保留.这是一个比用专业系统模仿人类思维有用的使用方法,因为提出一个类似的情况,和采用一些修改,似乎不言自明,而且比人类更直观.所以支持不同事例的设计工具已经在诸多领域中发展起来,如在注射成型及设计、建筑设计、模具设计投死, 规划过程中,还有夹具设计. 孙用六个数字组成代码参数,包括工件的形状、机械部分、轴衬,第一定位装置,第二定位装置和夹紧装置. 但这个系统不能用于除钻床夹具外的其他夹具类型,不能解决储存需要保留的同一参数代码的问题,这在CBR中是非常重要的.1事例参数和事例图书馆的建立1.1事例参数事例参数应该由工件的所有的特征组成,来区别不同的夹具. 使用他们能够使操作方便. 因为零件的形状是多种多样的, 在生产企业中制造的技术要求也不断发展,许多特征作被用做事例参数将会使搜索速度降低,其主要特征是不重要的,因为分配给每个特征的比重必须减少. 另一方面,事例参数包含所有的特征是困难的。

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基于事例推理的夹具设计研究与应用摘要:根据基于事例的设计方法,提出采用工序件的特征信息和夹具的结构特征信息来描述夹具的相似性,并建立了包括这2方面主要特征信息为基础的事例索引码,设计了事例库的结构形式,创建了层次化的事例组织方式;同时,提出了基于知识引导的夹具事例检索算法,以及事例的修改和采用同族事例码进行相似事例的存贮,形成了基于事例推理的夹具设计.所开发的原型系统在型号工程夹具设计等项目的设计过程中得到了应用,并取得了令人满意的使用效果.关键词: 基于事例的推理夹具设计CAD夹具是以确定工件安全定位准确为目的的装置,并在加工过程中保持工件与刀具或机床的位置一致不变。

因为夹具的结构依赖于产品的特点和在企业规划中加工工序的地位,所以它的设计是制造过程中的瓶颈,制约着效率的提高. 夹具设计是一个复杂的过程,需要有从大量的设计论文中了解质量知识的经验,这些设计论文包括工件的结构设计、涉及加工工艺,和加工环境。

当用这些擅长绘制详细设计图的传统的CAD工具(如Unigraphics、CATIA、Pro/E)时,这仍然是一项非常耗时的工作,但是利用以往的设计经验和资源也不能提供一些益处,而这正是提高效率的关键因素. 基于事例推理(CBR) 的方法适应以往个案解决的办法,建立一个新问题的方法,主要有以下四步骤:检索、利用、修改,并保留.这是一个比用专业系统模仿人类思维有用的使用方法,因为提出一个类似的情况,和采用一些修改,似乎不言自明,而且比人类更直观.所以支持不同事例的设计工具已经在诸多领域中发展起来,如在注射成型及设计、建筑设计、模具设计投死, 规划过程中,还有夹具设计. 孙用六个数字组成代码参数,包括工件的形状、机械部分、轴衬,第一定位装置,第二定位装置和夹紧装置. 但这个系统不能用于除钻床夹具外的其他夹具类型,不能解决储存需要保留的同一参数代码的问题,这在CBR中是非常重要的.1事例参数和事例图书馆的建立1.1事例参数事例参数应该由工件的所有的特征组成,来区别不同的夹具. 使用他们能够使操作方便. 因为零件的形状是多种多样的, 在生产企业中制造的技术要求也不断发展,许多特征作被用做事例参数将会使搜索速度降低,其主要特征是不重要的,因为分配给每个特征的比重必须减少. 另一方面,事例参数包含所有的特征是困难的。

因此,考虑到实际和快速设计的需求,事例参数要包含工件的主要特征和夹具的结构。

事例参数代码由16位数组成:13位数是事例特征3位数是事例识别数字。

前13位数代表13个特征。

每个数字与特征的一个属性相一致,这可能是"*"、"?"、"1"、"2",…,"A"、"B",…,"Z",…,等其中的一个。

其中,"*"是指任何一个,"?"代表不确定,"0"代表没有。

系统规定:夹具的类型,工件的形状,位置模式不能是"*"和"?"。

在设计系统时,三个项目的属性信息没有这些选择,这就意味着必须选择确定的属性。

最后三位数是事例识别号码,如果事例特征的13位数是一样的,这三个数字就用来区别他们。

该系统还规定:"000"是用于修正的一个典型事例,其他事例"001"、"002"、…,这些是用于设计师查找参考事例的. 如果其中一个偶尔需要改变成典型事例,首先它必须要求改成"000",前面的自动变成参考事例.事例索引码的结构如图1所示。

1—夹具类型;6—工件重量;11—夹紧模型;2—工件形状;7—工件刚度;12—夹具体;3—工件材料;8—加工内容;13—其他;4—批量;9—过程所有物;14到16—事例识别码;5—工件比例;10—定位模型;图1 事例索引码的结构1.2事例库事例库由许多预定义的事例组成。

事例的描述是基于事例推理的最重要的问题之一。

所以由索引码复合。

1.3 事例的层次化夹具的结构相似被认为是整个夹具,成分和内容相似。

所以,整个夹具事例库,成分事例库,夹具的成分事例库形成相同。

整个夹具的设计资料通常是由工件资料和工件加工资料组成,这就意味着夹具的设计应满足特别功能的需求.全部夹具事例是由功能成分组成,它是用功能成分的名字和数字来进行描述的。

成分事例代表成员(成分功能和其他结构成分,主要驱动参数,数字,和它们的约束关系)。

成分事例(夹具的最低层)是功能成分和和其他成分的结构。

在现代夹具设计中有很多参数化准件和普通非标准件。

所以成分事例图书馆应记录特殊参数和保持它们的方法。

2事例修改的策略在基于事例的夹具设计中,最重要的是相似点的修改,这样能有助于获得最相似的事例,以及缩短适应时间。

根据夹具设计的需求,事例修改的策略使最接近的事例方法和知识指导结合起来。

首先在深度上查找,然后在宽度上;知识指导策略意味着在来自客观事物根源的知识规则上查找,这就要首先查找固定类型,然后查找工件的形状,第三查找定位方法。

例如,如果事例索引码包括夹具类型的磨削夹具,就只查找所有的磨削夹具,然后查找工件形状的盒子,第三查找一个平面两个销的定位方法。

如果没有合适的,就查找深度标点,然后回到最上层,然后再找所有与宽度相关的事例。

修改方法:1)根据夹具事例库的事例索引信息,查找有关事例库。

2)将事例索引码与事例库的每个事例码匹配,然后计算相似尺寸的价值。

3)整理相似尺寸的次序,最大的架子是最类似的事例。

两个事例之间的相似点是基于两个事例特征之间的相似点。

相似点尺寸的计算依靠特征的类型。

相似点的价值可以通过数字化的价值来计算,例如比较重量分别是50kg 和20kg的工件。

非数字化的价值也能计算,例如,现在前13位索引码都是非数字化的价值。

一个夹具的相似尺寸的计算公式如下:其中S表示通用夹具的相似尺寸,n表示索引特性数,表示每个特性的重量,表示事例库中特性和相关夹具的特性的相似尺寸。

同时,,数值计算如下:其中表示第i个特征的索引特性值,表示事例库中第j个事例的第i个特征的特性值。

所以有两种方法选择相似夹具。

一个方法是建立数值。

如果通用事例的相似尺寸值比给定的数值小,这些事例就不能选来作相似事例。

事例库最初建立的时候,只有一些事例,数值可以建小一点。

如果有大量的相似事例,数值就应该建的大一些。

另外一个方法是只建立相似事例的数字(例如10),这是类型单里相似尺寸的最大值。

3 事例的修改和存储3.1事例的修改夹具设计中相似事例的修改包括以下三个阶段:1)成分的替代2)保持形式不变,调整成分的特性3)模型重新设计如果夹具的成分是普通的物品,它们能通过使用工具被修改,代替以及删除,这些已经被设计好了。

3.2事例的存储在将一个新的事例保存到事例库之前,设计者必须考虑保存是否有价值。

如果这个事例不能增加系统的知识,就没有必要把它保存到事例库里。

如果它有价值的话,设计者在保存之前必须分析一下,看看这个事例是否作为标准事例或参考事例被存储了。

一个标准事例是一个描述同族事例主要特征的标准。

一个同族事例是有事例库中索引码前13位相同而最后三位不同的那些事例组成的。

一个标准事例的最后三位通常是“000”。

一个参考事例属于同族标准事例,最后三位用不同数字区分。

从被解释的概念中,可采用以下方法:1)如果一个新的事例和任何一个存在的事例族一致,和一个存在的标准事例的前13位数相同,那么这个事例就不能存储因为已经这种标准事例了。

或者只能作为一个参考事例保存(最后三位不是“000”,而且和其它的不一样)在事例库中。

2)如果一个新的事例和任何一个存在的事例族一致,并且被认为代替这个事例族要比以前的标准事例好,那么这个标准事例就被这个新的事例代替,以前的标准事例作为一个参考事例保存。

3)如果一个新的事例和任何一个存在的事例族不一致,一个新的事例族将会自动产生,并作为标准事例保存到事例库中。

4夹具设计中基于事例推理的过程根据夹具设计的特性,夹具设计的基本信息,例如夹具的名字,零件,生产和设计者等等,必须先输入。

然后,输入或设计工件的模型。

输入有关工件的细节信息,建立事例索引码,然后CBR开始依靠相似尺寸查找相似事例,选出最相似的事例。

如果需要的话,事例要满足通用性设计,再存储到事例库中。

程序流程图如图2所示图2 基于事例推理的夹具设计流程图5基于事例推理的夹具设计说明这是一个工件如图3所示。

材料是45钢,底座,形状为块状,生产批量为中批等。

需要设计成一个用来旋转孔的旋转夹具。

图3 需要设计夹具的一个工件(最大尺寸80mmx49mmx22mm)工件的特征值,属性值,事例索引码和重量在表1中列出。

表1 工件的事例索引码和重量特征名称特性值索引码重量夹具类型车床夹具 1 100工件形状块状9 90工件材料中碳钢 3 70批量中批 2 60工件比例小 5 60工件重量轻 5 60工件刚度硬度强 1 60加工内容孔 3 80程序要求完成加工 3 70定位方法三个平面 1 100夹紧方法不确定?90夹具体复合 4 80其他没有0 60通过查找和计算相似点,最相似的事例的事例索引码是19325513321402000,细节信息在表2中列出。

表2 最相似事例的事例索引码特征名称特性值索引码夹具类型车床夹具 1工件形状块状9工件材料中碳钢 3批量中批 2工件比例小 5工件重量轻 5工件刚度硬度强 1加工内容孔 3程序要求完成加工 3定位方法三个平面 1夹紧方法不确定?夹具体复合 4其他没有0相似点的计算如下:所以夹具的相似尺寸值是0.806,这是在事例库中用于设计的最相似的事例,最相似的事例的结构如图4所示图4 最相似的夹具当成分替代,修改定位模型和夹紧模型,以及调节相关尺寸之后,新的夹具被设计出来,图形如图6所示图5 需要设计的新夹具因为在事例库中没有相似夹具,新夹具被储存到事例库中。

事例索引码是19325523311402000。

6 结论基于事例推理,作为一个问题解决的方法,是一个比模仿人类思想的专业系统更有效的方法,已经在很多难获取知识的领域里得到发展。

基于事例推理的优点如下:它和人类的思想很相似;一个事例库通过保存新事例获得自学能力,它比有惯例库更快更容易,它可以更好的传递和解释新的知识,这和惯例库有很大的不同。

基于事例推理中提出的一个夹具设计的框架已经被实行了,使用的是支持基础数据的VC++,UG电脑绘图软件。

这个框架也已经和普通成分库和典型夹具库结合起来。

这个发展的标准系统,用于航空项目,帮助夹具设计者提高设计效率和重新使用先前的设计资源。

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