夹具设计英文文献翻译
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
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。
夹具设计英文文献
A review and analysis of current computer-aided fixture design approachesIain Boyle, Yiming Rong, David C. BrownKeywords:Computer-aided fixture designFixture designFixture planningFixture verificationSetup planningUnit designABSTRACTA key characteristic of the modern market place is the consumer demand for variety. To respond effectively to this demand, manufacturers need to ensure that their manufacturing practices are sufficiently flexible to allow them to achieve rapid product development. Fixturing, which involves using fixtures to secure work pieces during machining so that they can be transformed into parts that meet required design specifications, is a significant contributing factor towards achieving manufacturing flexibility. To enable flexible fixturing, considerable levels of research effort have been devoted to supporting the process of fixture design through the development of computer-aided fixture design (CAFD) tools and approaches. This paper contains a review of these research efforts. Over seventy-five CAFD tools and approaches are reviewed in terms of the fixture design phases they support and the underlying technology upon which they are based. The primary conclusion of the review is that while significant advances have been made in supporting fixture design, there are primarily two research issues that require further effort. The first of these is that current CAFD research is segmented in nature and there remains a need to provide more cohesive fixture design support. Secondly, a greater focus is required on supporting the detailed design of a fixture’s physical structure.2010 Elsevier Ltd. All rights reserved. Contents1. Introduction (2)2. Fixture design (2)3. Current CAFD approaches (4)3.1 Setup planning (4)3.1.1 Approaches to setup planning (4)3.2 Fixture planning (4)3.2.1 Approaches to defining the fixturing requirement (6)3.2.2 Approaches to non-optimized layout planning (6)3.2.3 Approaches to layout planning optimization (6)3.3 Unit design (7)3.3.1 Approaches to conceptual unit design (7)3.3.2 Approaches to detailed unit design (7)3.4 Verification (8)3.4.1 Approaches to constraining requirements verification (8)3.4.2 Approaches to tolerance requirements verification (8)3.4.3 Approaches to collision detection requirements verification (8)3.4.4 Approaches to usability and affordability requirements verification (9)3.5 Representation of fixturing information (9)4. An analysis of CAFD research (9)4.1 The segmented nature of CAFD research (9)4.2 Effectively supporting unit design (10)4.3 Comprehensively formulating the fixturing requirement (10)4.4 Validating CAFD research outputs (10)5. Conclusion (10)References (10)1. IntroductionA key concern for manufacturing companies is developing the ability to design and produce a variety of high quality products within short timeframes. Quick release of a new product into the market place, ahead of any competitors, is a crucial factor in being able to secure a higher percentage of the market place and increased profit margin. As a result of the consumer desire for variety, batch production of products is now more the norm than mass production, which has resulted in the need for manufacturers to develop flexible manufacturing practices to achieve a rapid turnaround in product development.A number of factors contribute to an organization’s ability to achieve flexible manufacturing, one of which is the use of fixtures during production in which work pieces go through a number of machining operations to produce individual parts which are subsequently assembled into products. Fixtures are used to rapidly, accurately, and securely position work pieces during machining such that all machined parts fall within the design specifications for that part. This accuracy facilitates the interchangeability of parts that is prevalent in much of modern manufacturing where many different products feature common parts.The costs associated with fixturing can account for 10–20% of the total cost of a manufacturing system [1]. These costs relate not only to fixture manufacture, assembly, and operation, but also to their design. Hence there are significant benefits to be reaped by reducing the design costs associated with fixturing and two approaches have been adopted in pursuit of this aim. One has concentrated on developing flexible fixturing systems, such as the use of phase-changing materials to hold work pieces in place [2] and the development of commercial modular fixture systems. However, the significant limitation of the flexible fixturing mantra is that it does not address the difficulty of designing fixtures. To combat this problem, a second research approach has been to develop computer-aided fixture design (CAFD) systems that support and simplify the fixture design process and it is this research that is reviewed within this paper.Section 2 describes the principal phases of and the wide variety of requirements driving the fixture design process. Subsequently in Section 3 an overview of research efforts that havefocused upon the development of techniques and tools for supporting these individual phases of the design process is provided. Section 4 critiques these efforts to identify current gaps in CAFD research, and finally the paper concludes by offering some potential directions for future CAFD research. Before proceeding, it is worth noting that there have been previous reviews of fixturing research, most recently Bi and Zhang [1] and Pehlivan and Summers [3]. Bi and Zhang, while providing some details on CAFD research, tend to focus upon the development of flexible fixturing systems, and Pehlivan and Summers focus upon information integration within fixture design. The value of this paper is that it provides an in-depth review and critique of current CAFD techniques and tools and how they provide support across the entire fixture design process.2. Fixture designThis section outlines the main features of fixtures and more pertinently of the fixture design process against which research efforts will be reviewed and critiqued in Sections 3 and 4, respectively. Physically a fixture consists of devices that support and clamp a work piece [4,5]. Fig.1 represents a typical example of a fixture in which the work piece rests on locators that accurately locate it. Clamps hold the work piece against the locators during machining thus securing the work piece’s location. The locating units themselves consist of the locator supporting unit and the locator that contacts the work piece. The clamping units consist of a clamp supporting unit and a clamp that contacts the work piece and exerts a clamping force to restrain it.Typically the design process by which such fixtures are created has four phases: setup planning, fixture planning, unit design, and verification, as illustrated in Fig. 2 , which is adapted from Kang et al. [6]. During setup planning work piece and machining information is analyzed to determine the number of setups required to perform all necessary machining operations and the appropriate locating datums for each setup. A setup represents the combination of processes that can be performed on a work piece without having to alter the position or orientation of the work piece manually. To generate a fixture for each setup the fixture planning, unit design, and verification phases are executed.During fixture planning, the fixturing requirements for a setup are generated and the layout plan, which represents the first step towards a solution to these requirements is generated. This layout plan details the work piece surfaces with which the fixture’s locating and clamping units will establish contact, together with the surface positions of the locating and clamping points. The number and position of locating points must be such that a work piece’s six degrees of freedom (Fig. 3 ) are adequately constrained during machining [7] and there are a variety of conceptual locating point layouts that can facilitate this, such as the 3-2-1 locating principle [4]. In the third phase, suitable unit designs (i.e., the locating and clamping units) are generated and the fixture is subsequently tested during the verification phase to ensure that it satisfies the fixturing requirements driving the design process. It is worth noting that verification of setups and fixture plans can take place as they are generated and prior to unit design.Fixturing requirements, which although not shown in Kang et al.[6] are typically generated during the fixture planning phase, can be grouped into six class es ( Table 1 ). The ‘‘physical’’requirements class is the most basic and relates to ensuring the fixture can physically support the work piece. The ‘‘tolerance’’requirements relate to ensuring that the locating tolerances aresufficient to locate the work piece accurately and similarly the‘‘constraining’’ requirements focus on maintaining this accuracy as the work piece and fixture are subjected to machining forces. The ‘‘affordability’’ requirements relate to ensuring the fixture represents value, for example in terms of material, operating, and assembly/disassembly costs.The ‘‘collision detection’’ requirements focus upon ensuring that the fixture does not collide with the machining path, the work piece, or indeed itself. The ‘‘usability’’ requirements relate to fixture ergonomics and include for example needs related to ensuring that a fixture features error-proofing to prevent incorrect insertion of a work piece, and chip shedding, where the fixture assists in the removal of machined chips from the work piece.As with many design situations, the conflicting nature of these requirements is problematic. For example a heavy fixture can be advantageous in terms of stability but can adversely affect cost (due to increased material costs) and usability (because the increased weight may hinder manual handling). Such conflicts add to the complexity of fixture design and contribute to the need for the CAFD research reviewed in Section 3.Table 1Fixturing requirements.Generic requirement Abstract sub-requirement examplesPhysical ●The fixture must be physically capable of accommodatingthe work piece geometry and weight.●The fixture must allow access to the work piece features tobe machined.Toleranc e ●The fixture locating tolerances should be sufficient to satisfypart design tolerances.Constraining●The fixture shall ensure work piece stability (i.e., ensure thatwork piece force and moment equilibrium are maintained).●The fixture shall ensure that the fixture/work piece stiffness issufficient to prevent deformation from occurring that could resultin design tolerances not being achieved.Affordabilit y ●The fixture cost shall not exceed desired levels.●The fixture assembly/disassembly times shall not exceeddesired levels.●The fixture operation time shall not exceed desired levels. CollisionPrevention●The fixture shall not cause tool path–fixture collisions to occur.●The fixture shall cause work piece–fixture collisions to occur(other than at the designated locating and clamping positions).●The fixture shall not cause fixture–fixture collisions to occur(other than at the designated fixture component connectionpoints).Usabilit y ●The fixture weight shall not exceed desired levels.●The fixture shall not cause surface damage at the workpiece/fixture interface.●The fixture shall provide tool guidance to designated workpiece features.●The fixture shall ensure error-proofing (i.e., the fixture shouldprevent incorrect insertion of the work piece into the fixture).●The fixture shall facilitate chip shedding (i.e., the fixture shouldprovide a means for allowing machined chips to flow awayfrom the work piece and fixture).3. Current CAFD approachesThis section describes current CAFD research efforts, focusing on the manner in which they support the four phases of fixture design. Table 2 provides a summary of research efforts based upon the design phases they support, the fixture requirements they seek to address (boldtext highlights that the requirement is addressed to a significant degree of depth, whilst normal text that the degree of depth is lesser in nature), and the underlying technology upon which they are primarily based. Sections 3.1–3.4 describes different approaches for supporting setup planning, fixture planning, unit design, and verification, respectively. In addition, Section 3.5 discusses CAFD research efforts with regard to representing fixturing information.3.1. Setup planningSetup planning involves the identification of machining setups, where an individual setup defines the features that can be machined on a work piece without having to alter the position or orientation of the work piece manually. Thereafter, the remaining phases of the design process focus on developing individual fixtures for each setup that secure the work piece. From a fixturing viewpoint, the key outputs from the setup planning stage are the identification of each required setup and the locating datums (i.e., the primary surfaces that will be used to locate the work piece in the fixture).The key task within setup planning is the grouping or clustering of features that can be machined within a single setup. Machining features can be defined as the volume swept by a cutting tool, and typical examples include holes, slots, surfaces, and pockets [8]. Clustering of these features into individual setups is dependent upon a number of factors (including the tolerance dependencies between features, the capability of the machine tools that will be used to create the features, the direction of the cutting tool approach, and the feature machining precedence order), and a number of techniques have been developed to support setup planning. Graph theory and heuristic reasoning are the most common techniques used to support setup planning, although matrix based techniques and neural networks have also been employed.3.1.1. Approaches to setup planningThe use of graph theory to determine and represent setups has been a particularly popular approach [9–11]. Graphs consist of two sets of elements: vertices, which represent work piece features, and edges, which represent the relationships that exist between features and drive setup identification. Their nature can vary, for example in Sarma and Wright [9] consideration of feature machining precedence relationships is prominent, whereas Huang and Zhang [10] focus upon thetolerance relationships that exist between features. Given that these edges can be weighted in accordance with the tolerance magnitudes, this graph approach can also facilitate the identification of setups that can minimize tolerance stack up errors between setups through the grouping of tight tolerances. However, this can prove problematic given the difficulty of comparing the magnitude of different tolerance types to each other thus Huang [12] includes the use of tolerance factors [13] as a means of facilitating such comparisons, which are refined and extended by Huang and Liu [14] to cater for a greater variety of tolerance types and the case of multiple tolerance requirements being associated with the same set of features.While some methods use undirected graphs to assist setup identification [11] , Yao et al. [15] , Zhang and Lin [16] , and Zhang et al. [17] use directed graphs that facilitate the determination and explicit representation of which features should be used as locating datums ( Fig. 4 ) in addition to setup identification and sequencing. Also, Yao et al. refine the identified setups through consideration of available machine tool capability in a two stage setup planning process.Experiential knowledge, in the form of heuristic reasoning, has also been used to assist setup planning. Its popularity stems from the fact that fixture design effectiveness has been considered to be dependent upon the experience of the fixture designer [18] .To support setup planning, such knowledge has typically been held in the form of empirically derived heuristic rules, although object oriented approaches have on occasion been adopted [19] . For example Gologlu [20] uses heuristic rules together with geometric reasoning to support feature clustering, feature machining precedence, and locating datum selection. Within such heuristic approaches, the focus tends to fall upon rules concerning the physical nature of features and machining processes used to create them [21, 22]. Although some techniques do include feature tolerance considerations [23], their depth of analysis can be less than that found within the graph based techniques [24]. Similarly, kinematic approaches [25] have been used to facilitate a deeper analysis of the impact of tool approach directions upon feature clustering than is typically achieved using rule-based approaches. However, it is worth noting that graph based approaches are often augmented with experiential rule-bases to increase their overall effectiveness [16] .Matrix based approaches have also been used to support setup planning, in which a matrix defining feature clusters is generated and subsequently refined. Ong et al. [26] determine a feature precedence matrix outlining the order in which features can be machined, which is then optimized against a number of cost indicators (such as machine tool cost, change over time, etc.) in a hybrid genetic algorithm-simulated annealing approach through consideration of dynamically changing machine tool capabilities. Hebbal and Mehta [27] generate an initial feature grouping matrix based upon the machine tool approach direction for each feature which is subsequently refined through the application of algorithms that consider locating faces and feature tolerances.Alternatively, the use of neural networks to support setup planning has also been investigated. Neural networks are interconnected networks of simple elements, where the interconnections are ‘‘learned’’ from a set of example data. Once educated, these networks can generate solutions for new problems fed into the network. Ming and Mak [28] use a neural network approach in which feature precedence, tool approach direction, and tolerance relationships are fed into a Kohonen self-organizing neural network to group operations for individual features into setups.3.2. Fixture planningFixture planning involves the comprehensive definition of a fixturing requirement in terms ofthe physical, tolerance, constraining, affordability, collision prevention, and usability requirements listed in Table 1 , and the creation of a fixture layout plan. The layout plan represents the first part of the fixture solution to these requirements, and specifies the position of the locating and clamping points on the work piece. Many layout planning approaches feature verification, particularly with regard to the constraining requirements. Typically this verification forms part of a feedback loop that seeks to optimize the layout plan with respect to these requirements. Techniques used to support fixture planning are now discussed with respect to fixture requirement definition, layout planning, and layout optimization.Fig. 4. A work piece (a) and its directed graphs showing the locating datums (b) (adapted from Zhang et al. [17] ).3.2.1. Approaches to defining the fixturing requirementComprehensive fixture requirement definition has received limited attention, primarily focusing upon the definition of individual requirements within the physical, tolerance, and constraining requirements. For example, Zhang et al. [17] under-take tolerance requirement definition through an analysis of work piece feature tolerances to determine the allowed tolerance at each locating point and the decomposition of that tolerance into its sources. The allowed locating point accuracy is composed of a number of factors, such as the locating unit tolerance, the machine tool tolerance, the work piece deformation at the locating point, and so on. These decomposed tolerance requirements can subsequently drive fixture design: e.g., the tolerance of the locating unit developed in the unit design phase cannot exceed the specified locating unit tolerance. In a similar individualistic vein, definition of the clamping force requirements that clamping units must achieve has also received attention [29,30].In a more holistic approach, Boyle et al. [31] facilitate a comprehensive requirement specification through the use of skeleton requirement sets that provide an initial decomposition of the requirements listed in Table 1, and which are subsequently refined through a series of analyses and interaction with the fixture designer. Hunter et al. [32,33] also focus on functional requirement driven fixture design, but restrict their focus primarily to the physical and constraining requirements.3.2.2. Approaches to non-optimized layout planningLayout planning is concerned with the identification of the locating principle, which defines the number and general arrangement of locating and clamping points, the work piece surfaces they contact, and the surface coordinate positions where contact occurs. For non-optimized layoutplanning, approaches based upon the re-use of experiential knowledge have been used. In addition to rule-based approaches [20,34,35] that are similar in nature to those discussed in Section 3.1, case-based reasoning has also been used. CBR is a general problem solving technique that uses specific knowledge of previous problems to solve new ones. In applying this approach to layout planning, a layout plan for a work piece is obtained by retrieving the plan used for a similar work piece from a case library containing knowledge of previous work pieces and their layout plans [18,36,37]. Work piece similarity is typically characterized through indexing work pieces according to their part family classification, tolerances, features, and so on. Lin and Huang [38] adopt a similar work piece classification approach, but retrieve layout plans using a neural network. Further work has sought to verify layout plans and repair them if necessary. For example Roy and Liao [39] perform a work piece deformation analysis and if deformation is too great employ heuristic rules to relocate and retest locating and clamping positions.3.2.3. Approaches to layout planning optimizationLayout plan optimization is common within CAFD and occurs with respect to work piece stability and deformation, which are both constraining requirements. Stability based optimization typically focuses upon ensuring a layout plan satisfies the kinematic form closure constraint (in which a set of contacts completely constrain infinitesimal part motion) and augmenting this with optimization against some form of stability based requirement, such as minimizing forces at the locating and/or clamping points [40–42] . Wu and Chan [43] focused on optimizing stability (measuring stability is discussed in Section 3.4) using a Genetic Algorithm (GA), which is a technique frequently employed in deformation based optimization.GAs, which are an example of evolutionary algorithms, are often used to solve optimization problems and draw their inspiration from biological evolution. Applying GAs in support of fixture planning, potential layout plan solutions are encoded as binary strings, tested, evaluated, and subjected to ‘‘biological’’ modification through reproduction, mutation, and crossover to generate improved solutions until an optimal state is reached. Typically deformation testing is employed using a finite element analysis in which a work piece is discretized to create a series of nodes that represent potential locating and clamping contact points, as performed for example by Kashyap and DeVries [44] . Sets of contact points are encoded and tested, and the GA used to develop new contact point sets until an optimum is reached that minimizes work piece deformation caused by machining and clamping forces [45,46]. Rather than use nodes, some CAFD approaches use geometric data (such as spatial coordinates) in the GA, which can offer improved accuracy as they account for the physical distance that exists between nodes [47,48].Pseudo gradient techniques [49] have also been employed to achieve optimization [50,51]. Vallapuzha et al. [52] compared the effectiveness of GA and pseudo gradient optimization, concluding that GAs provided higher quality optimizations given their ability to search for global solutions, whereas pseudo gradient techniques tended to converge on local optimums.Rather than concentrating on fixture designs for individual parts, Kong and Ceglarek [53] define a method that identifies the fixture workspace for a family of parts based on the individual configuration of the fixture locating layout for each part. The method uses Procrustes analysis to identify a preliminary workspace layout that is subjected to pairwise optimization of fixture configurations for a given part family to determine the best superposition of locating points for a family of parts that can be assembled on a single reconfigurable assembly fixture. This buildsupon earlier work by Lee et al. [54] through attempting to simplify the computational demands of the optimization algorithm.3.3. Unit designUnit design involves both the conceptual and detailed definition of the locating and clamping units of a fixture, together with the base plate to which they are attached (Fig. 5). These units consist of a locator or clamp that contacts the work piece and is itself attached to a structural support, which in turn connects with the base plate. These structural supports serve multiple functions, for example providing the locating and clamping units with sufficient rigidity such that the fixture can withstand applied machining and clamping forces and thus result in the part feature design tolerances being obtained, and allowing the clamp or locator to contact the work piece at the appropriate position. Unit design has in general received less attention than both fixture planning and verification, but a number of techniques have been applied to support both conceptual and detailed unit design.3.3.1. Approaches to conceptual unit designConceptual unit design has focused upon the definition of the types and numbers of elements that an individual unit should comprise, as well as their general layout. There are a wide variety of locators, clamps, and structural support elements, each of which can be more suited to some fixturing problems than others. As with both setup planning and fixture layout planning, rule-based approaches have been adopted to support conceptual unit design, in which heuristic rules are used to select preferred elements from which the units should be constructed in response to considerations such as work piece contact features (surface type, surface texture, etc.) and machining operations within the setup [35,55–58]. In addition to using heuristic rules as a means of generating conceptual designs, Kumar et al.[59] use an inductive reasoning technique to create decision trees from which such fixturing rules can be obtained through examination of each decision tree path.Neural network approaches have also been used to support conceptual unit design. Kumar et al. [60] use a combined GA/neural network approach in which a neural network is trained with a selection of previous design problems and their solutions. A GA generates possible solutionswhich are evaluated using the neural network, which subsequently guides the GA. Lin and Huang[38] also use a neural network in a simplified case-based reasoning (CBR) approach in which fixturing problems are coded in terms of their geometrical structure and a neural network used to find similar work pieces and their unit designs. In contrast, Wang and Rong[37] and Boyle et al.[31] use a conventional CBR approach to retrieve units in which the fixturing functional requirements form the basis of retrieval, which are then subject to refinement and/or modification during detailed unit design.3.3.2. Approaches to detailed unit designMany, but not all systems that perform conceptual design also perform detailed design, where the dominant techniques are rule, geometry, and behavior based. Detailed design involves the definition of the units in terms of their dimensions, material types, and so on. Geometry, in particular the acting height of locating and clamping units, plays a key role in the design of individual units in which the objective is to select and assemble defined unit elements to provide a unit of suitable acting height [61,62]. An et al. [63] developed a geometry based system in which the dimensions of individual elements were generated in relation to the primary dimension of that element (typically its required height) through parametric dimension relationships. This was augmented with a relationship knowledge base of how different elements could be configured to form a single unit. Similarly, Peng et al. [64] use geometric constraint reasoning to assist in the assembly of user selected elements to form individual units in a more interactive approach.Alternatively, rule-based approaches have also been used to define detailed units, in which work piece and fixture layout information (i.e., the locating and clamping positions) is reasoned over using design rules to select and assemble appropriately sized elements [32,55,56] . In contrast, Mervyn et al. [65] adopt an evolutionary algorithm approach to the development of units, in which layout planning and unit design take place concurrently until a satisfactory solution is reached.Typically, rule and geometry based approaches do not explicitly consider the required strength of units during their design. However for a fixture to achieve its function, it must be able to withstand the machining and clamping forces imposed upon it such that part design tolerances can be met. To address this, a number of behaviorally driven approaches to unit design have been developed that focus upon ensuring units have sufficient strength. Cecil [66] performed some preliminary work on dimensioning strap clamps to prevent failure by stress fracture, but does not consider tolerances or the supporting structural unit. Hurtado and Melkote [67] developed a model for the synthesis of fixturing configurations in simple pin-array type flexible machining fixtures, in which the minimum number of pins, their position, and dimensions are determined that can achieve stability and stiffness goals for a work piece through consideration of the fixture/work piece stiffness matrix, and extended this for modular fixtures [68] . Boyle et al. [31] also consider the required stiffness of more complex unit designs within their case-based reasoning method. Having retrieved a conceptual design that offers the correct type of function, this design’s physical structure is then adapted using dynamically selected adaptation strategies until it offers the correct level of stiffness.3.4. VerificationVerification focuses upon ensuring that developed fixture designs (in terms of their setup plans, layout plans, and physical units) satisfy the fixturing requirements. It should be noted from。
变速箱换挡叉的加工工艺及夹具设计(中英文文献)
毕业论文附件材料目录1 英文文献翻译 (1)1.1 Shift gearbox (1)1.2 变速箱的换挡方式 (12)1 英文文献翻译1.1 Shift gearboxClassification usually gearbox as follows:Manual transmissionThe general automatic gearbox / mon automatic transmission with tiptronicCVT stepless gearbox with gear box of the /CVTDual clutch gearboxSequential gearbox(1) manual gearboxManual transmission, also known as manual gear, English name is manual transmission, referred to as MT, which push the shift lever to change gears meshing position inside the transmission, changing the transmission ratio, so as to achieve the purpose of speed. Step on the clutch, can move the shift lever.The working principle of a manual gearboxThe manual gear box is posed of different gear ratio of the gear group, its basic principle is through the gear group work in different, to realize the transformation of gear ratio. As the key link for power distribution, transmission must have the power input shaft and the output shaft of the big two, together constitute the transmission gear, is a manual transmission is the most basic ponent. The power input is connected with the clutch shaft clutch transmission, from the power to directly through the input shaft to the group, the gear set is posed of different diameter gear, gear power transmission effectof different proportion reached is pletely different, the usual shift driving also refers to change gear ratio.Next, let us through a simple model to tell you, the principle of manual gearbox shift. Below is a simple structural model of 3 axis 2 speed gearbox.The input shaft (green) is also called the first shaft, connected by a clutch and engine, shaft and the gear is a hard connected ponents. Red is called the intermediate gear shaft. Enter the two gear shaft and intermediate shaft is in constant mesh state, so when the input shaft rotates will drive shaft rotation. Yellow is the output shaft, it is also called the second shafts and connected to the drive shaft (only for rear wheel drive, the precursor is generally two), and then through the differential drive vehicles.When the wheel rotates the same with spline shaft to rotate together, at this time,blue gear shaft can occur on the spline shaft relative free rotation. Therefore, the engine stops, and the wheel is rotated, the blue gear and shaft in the stationary state, and the spline shaft with wheels. The principle and the rear axle of the bicycle flywheel is similar. Blue gear and spline shaft is posed of a sleeve to connect, sleeve with spline shaft to rotate, but also can be free to slide on the spline shaft to gear.With these, the shifting process is very good understanding, when connecting sleeve and a blue gear, engine power will be transmitted to the output shaft through the shaft, at the same time, blue gear left in free rotation, but because there is no and sleeve engaged, so it does not affect the spline shaft. If the sleeve between the two blue gear, the gearbox in neutral position, the two blue gear on the spline shaft rotate freely, without mutual interference.Principle of a conventional 5 speed manual gearbox shift is the same, only thegearbox structure increased the number of sleeve and the gear sets, so that it has more gear. But the reverse is based on the intermediate shaft (red) and the output shaft (blue) is added between a gear to achieve. Due to the increase of a gear, the reverse gear will always rotate toward other gear in the opposite direction. The gear because only to change gear rotation direction function, so it is also called the idler.5 block two shaft transmission structure, the input shaft and the driving gear are integrated into a whole, simplifies the structure and saves spaceIn addition to the traditional three axis manual gearbox, the widespread use of cars is two axis manual transmission, its structure and the three shaft of the gearbox is similar, only the input shaft and intermediate shaft as a shaft, therefore has the advantages of simple structure, small size advantages, in addition, it also has the middle gear transmission high efficiency, and low noise characteristics, so it is more suitable to be theprecursor home car general car transmission form, is currently the most widely used, its shortings is not set up direct gear, transmission and file than the design cannot be too high. While driving, three shaft gearbox used is still the traditional.Manual gearbox in general, is through the push rod is connected or cable to control the shift. Push rod shift control connection, more direct but vibration will be large; and the cable type although no vibration, but the shift is not very clear, it is each to have good and bad. In addition to shift the two pure mechanical control, in addition, and the use of electronic shift device of manual transmission, which can bine the merits of push and pull the shift between the good. This kind of gear box in the shift when the gear shift lever, shifting to the corresponding gear, the transmission will be motor drive the corresponding fork control sleeve and the gear is engaged, so that there is no gear is not clear, but the shift schedule can be controlled in the ideal range.So, a good manual transmission need to have what characteristic? The first transmission must have good gear handle, each gear position clear, have reasonable horizontal and vertical stroke, into the block resistance is small and with suction. What is more important is, the gear tooth between than arrangement must be reasonable. Because each gear position than distribution, directly affect the cohesion power vehicles moving in a smooth, usually require a low gear can effectively accelerate, high block to achieve high speed and efficient, and the distance between each block should be uniform, otherwise will be very easy to cause the channeling shift when the car.Analysis of the advantages and disadvantages of manual gearboxAdvantages Obviously, which is simple in structure, reliable performance,manufacturing and maintenance cost is low, and the transmission efficiency is high (theory will be more fuel-efficient), also, because it is pure mechanical control, shift reaction is fast, and can be more direct expression of driver's intention, and therefore more driving pleasure, these are the advantages of manual gearbox. But pared to automatic transmission, its operation is plicated, and frustration in gear switch when the obvious disadvantage is irreparable.(2) automatic gearboxAutomatic transmission AT, the full name of Auto Transmission, which is posed of hydraulic torque converter, posed of planetary gear and hydraulic control system, through the hydraulic transmission and gear bination to achieve variable speed moment.pared with the manual transmission, automatic transmission is very different in structure and usage. The manual is mainly regulated by different gear bination to change gear, and the automatic transmission is through the hydraulic transmission and gear bination to achieve the purpose of changing speed. Hydraulic torque converter is one of the most characteristic of the automatic gearbox parts, which is posed of a pump, turbine and guide wheel and other ponents, pump wheel and turbine is a bination of work, through the liquid pump wheel drives the turbine to rotate, and the wheel between the pump and turbine wheel through the reaction between the pump wheel and turbine implementation the speed difference and implementation of variable torque function, the driver, you only need to different intensity slam the pedal, the gearbox can automatically stop lifting. Since the torque converter automatic transmission torque range is not big enough, so in a later series several rows of planetary gear to improve efficiency, thehydraulic control system will change with the engine to manipulate the planetary gear, so as to realize the automatic transmission torque. In order to meet a variety of running process needs (such as parking, reversing), automatic transmission also has some manual shift lever position, like the P block (R block (anchor), after the block), block N (neutral), D (forward), block.From the performance that the more gear automatic gearbox, the car in the process of running more smoothly, acceleration is better, and more fuel-efficient. In addition to providing a fortable driving feeling, automatic transmission also has insurmountable defects. Dynamic automatic transmission response is not directly, which makes it in the "driving pleasure" slightly shortage. In addition, because of the use of hydraulic transmission, the automatic transmission gearbox transmission power loss.Tiptronic automatic transmissionHands appeared gearbox is in order to improve the automatic gearbox and operating economy and increase the setting, let the original puter automatic shift time back into the hands of drivers. At the same time, if in the city traffic in, or you can always switch back to automatic.A tiptronic automatic transmission is actually automatic gearbox, first appeared in a Porsche 911, manual gearbox electronic control system through the simulation of the operation of a manual gearbox. It appears, giving the driver a greater degree of freedom in the operation, can block up the blocking or shift paddles on the steering wheel to choose their own gear and shift the timing right, thereby greatly improving the driving pleasure.(3) CTV non-polar transmissionCVT (Continuously Variable Transmission), direct translation is a continuously variable transmission, which is continuously variable transmission. We often say, just as its name implies is that there is no clear and specific file, which operate on similar automatic gearbox, gear jump process but the ratio change is different from the automatic gearbox, but a continuous, so the power transmission continues smooth.CVT transmission system, the traditional gear by a pair of pulleys and a steel belt is replaced, each block is V structure is posed of two intervertebral disk, engine shaft is connected through a small pulley, steel belt drive pulley. Mystery lies in this special pulley: drive pulley structures CVT strange activity, divided into halves, can be close to or separate relative. Cone disc can tighten or open the thrust hydraulic, extrusion sheet steel chain so as to adjust the V slot width. When the cone disc inside mobile tightened, steel chain in the extrusion cones to center outside of the direction of movement (centrifugal direction), but moving to the center of the circle. In this way, steel chain drives the disc diameter increases, the transmission ratio is changed.The CVT gearbox what are the advantages?1, because there is no general automatic transmission gear, there will be no shift process of automatic transmission, shift the resulting sense of frustration will disappear, so the power output of CVT gearbox is linear, in actual driving very smooth.Theory of transmission system of 2 CVT, the gear can be an unlimited number of gear set, more freedom, the traditional transmission gear ratio, speed ratio and performance, fuel consumption, exhaust emissions balance, are more likely to achieve.3, the mechanical efficiency of CVT transmission, the province is oily considerably better than the automatic transmission mon, after manual gearbox, fuel economy is much better than.Since there are so many advantages, why not let all the cars using CVT gearbox? There are two factors:1, pared with the traditional automatic transmission, its cost is high; and the operation is undeserved word, the higher probability.2, CVT gearbox itself still has its shortings, is the transmission of the steel belt can withstand strength is limited, generally more than 2.8L capacity or power above 280N • M is its limit, but we also see that there are more and more cars such as Audi, or Nissan, has broken the limit, believe strip the problem will be solved gradually.(4) dual clutch gearboxDual clutch gearbox DCT, English name is Dual Clutch Transmission, because it has two clutches, so called "dual clutch transmission".Technology introducedDual clutch gearbox bines the advantages of manual transmission and automatic transmission, no torque converter, instead of using two sets of clutch, through two sets of clutch alternately work, to achieve seamless shift effect. Two clutches respectively control the odd block and even block, that is to say, in the shift before, DSG had the next gear meshing, after shifting instruction, DSG quickly sends instructions to the engine, the engine speed increases, the previous meshing gears quickly, while the first group of clutch fully liberalized, the pletion of a rise to block the action time, action andso on.Because without the torque converter, so the power of the engine can be fully played out, while the two clutch alternately work, shift time making, dynamic fault engine may be very limited. As the driver is the feeling that we are the most direct, switch gear action very quickly and smoothly, dynamic transmission process of almost uninterrupted, vehicle dynamic performance can be fully play. pared with the traditional automatic transmission with torque converter, the DSG shift more directly, the power loss is smaller, so the fuel consumption can be reduced by more than 10%.DeficienciesHowever, with the traditional automatic transmission ratio, DSG also has some inherent disadvantages, firstly it is because there is no use hydraulic torque converter, nor realize manual transmission "linkage" action, so for the small-displacement engine, low speed torque characteristic is not enough to be pletely exposed; secondly, because the DSG transmission using puter control, belonging to an intelligent transmission, it needs to send electronic signals to the engine block in the process of falling in the L /, the engine after reply, and the engine to be pleted with L / reduction gear. A large number of electronic ponents, but also increases the probability of its failure.The dual clutch mon with Volkswagen's DSG, Ford Powershift, Mitsubishi SST and Porsche PDK.(5) sequential gearboxSequential gearbox (AMT) is improved on the traditional manual gear transmission based on; it bines hydromechatronics automatic transmission has the advantages of bothAT and MT; AMT has the advantages of automatic transmission mon automatic transmission, and the retention efficiency of the original manual transmission gear transmission, the high cost of low, simple structure, easy manufacture. It is the reform in the present manual transmission, retained most of the original assembly, only to change the shift lever manual operating system part, the production of succession, to transform the input costs less, is very easy to be manufacturers to accept.The driver through the accelerator pedal and joystick to the electronic control unit (ECU) control signal transmission; electronic control unit collects the engine speed sensor, the speed sensor signal, the time to master the running state of the vehicle; electronic control unit (ECU) based on the best program according to these signals stored therein, optimal shifting rules, clutch fuzzy control rules engine oil, adaptive control law, action and temporal separation of the engine, clutch and transmission shift binding, the three to achieve the best matching. In order to obtain the excellent fuel economy and power performance and ability to smooth start and rapid shift, in order to achieve the desired results.But the AMT transmission is not perfect, the biggest disadvantage of AMT gearbox is shifting fort is poor, and generate power interruption in the process of shifting, the shift in the process of speed performance is not good.AMT mechanical gearbox, its basic structure and conventional manual gearbox consistent, generally only one input shaft and an output shaft (RWD usually a middle shaft), which generally is the input shaft 5 forward gear and output shaft gear is in constant mesh state, wherein the output shaft of the 1 gear and a reverse gear, 2 blockand the 3 block, 4 block and 5 block were shared by the three shift fork. The mechanism of two adjacent gear with a shifting mechanism, when the shift action, fork need once upon a gear defect, through neutral to the next gear gear meshing, due to three actions is the order, even if each action will be the time to a minimum, is still very difficult to obtain the shift speed fast enough."Independent innovation shift fork"The ISR gearbox has a unique structure, the gear arrangement it is different with the traditional AMT gearbox, also different from the dual clutch gearbox. The use of four independent shift fork, two stalls adjacent to the gear shift fork is posed of different control. Four independent fork respectively control 1 gear and reverse gear; block 3 and block 5, block 2 and block 4, block 6 and block 7, that is to say, from 1 until 6 block, two adjacent stalls are posed of two independent fork to respectively control.Because of this design, the shifting process can be further shortened: when two adjacent gear to gear switch, a shift fork and the current gear gear detachment, another gear meshing has already started, and a shift fork action and activates the electronic clutch three, because the action is almost synchronously, so that the whole time shorten. Lamborghini is pared originally claimed, performance is very good before the generation of the E-gear sequential gearbox, shift speed upgrade 40%, shift speed of 50 milliseconds is close to F1 gearbox level.Gear shift mechanism of ISR is driven by the electric hydraulic pump, a maximum of 60 bar pressure ensures the necessary operating speed, 7 hydraulic valve controls the gear shift mechanism of action, and the electric pump to provide power, double plateclutch tough also driven by hydraulic pressure, will be responsible for the torque of the 690Nm transmitted to the four wheels. Synchronizer gear ring is made from carbon fiber, not only wear but also reduce the overall quality of the gearbox.In the design process, the transmission is not only fast, shift quality is equally important, VOCIS design control procedure is also fully take into account the daily driving fort. The gearbox can choose three kinds of work modes: Strada (Road) or full automatic mode can provide fortable for shift operation oriented; Sport (motion) mode will postpone shifting node and provides a more rapid gear switch; Corsa (track) model can provide the best track shift strategy, the model can also provide the starting control, also is the ejection start function.1.2 变速箱的换挡方式通常变速箱的分类为以下几种：手动变速箱普通自动变速箱/普通自动变速箱带手自一体CVT无级变速箱/CVT带挡位的变速箱双离合变速箱序列变速箱(1) 手动变速箱手动变速器，也称手动挡，英文全称为manual transmission，简称MT，即用手拨动变速杆才能改变变速器内的齿轮啮合位置，改变传动比，从而到达变速的目的。
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。
夹具设计外文文献
以下是一篇关于夹具设计的外文文献示例：Title: Design and Optimization of Fixture for Manufacturing Systems: A ReviewAbstract: Fixtures play a critical role in manufacturing systems by securely holding the workpiece during various machining and assembly operations. It is essential to design efficient and effective fixtures to ensure accurate and reliable production processes. This paper presents a comprehensive review of fixture design and optimization techniques in manufacturing systems. Various methodologies, such as analytical, heuristic, and numerical approaches, are discussed. The paper also highlights the challenges and future research directions in fixture design and optimization.Keywords: fixture design, manufacturing systems, optimization, workpiece, machining, assemblyIntroduction: Fixtures are widely used in manufacturing systems to provide stability and positioncontrol for the workpiece during machining, welding, and assembly operations. The design and optimization of fixtures are critical for the overall performance and quality of the manufacturing process. This paper aims to review the existing literature on fixture design and optimization techniques to provide insights and guidelines for researchers and practitioners in the field.Methods: The review is based on a systematic analysis of published research articles, conference papers, and patents related to fixture design and optimization. Various search engines and databases were used to identify relevant literature. The selected papers were analyzed and categorized based on the methodology used, such as analytical, heuristic, and numerical approaches.Results: The review demonstrates that fixture design and optimization have been extensively studied in manufacturing systems. Analytical methods, such as mathematical modeling and kinematic analysis, arecommonly used for fixture layout and configuration design. Heuristic approaches, such as rule-based and expert system methods, provide intuitive and practical solutions for fixture design. Numerical optimization techniques, such as finite element analysis and genetic algorithms, offer advanced optimization methods for fixture design.Discussion: The review reveals several challenges in fixture design and optimization, such as the trade-off between fixture complexity and cost, the consideration of dynamic loading conditions, and the integration of advanced materials and technologies. Future research directions include the development of intelligent fixture systems, the application of virtual reality and augmented reality in fixture design, and the exploration of sustainable and eco-friendly fixture materials.Conclusion: Fixture design and optimization are crucial for manufacturing systems to achieve accurate and reliable production processes. This review providesa comprehensive overview of fixture design and optimization techniques in the existing literature. The findings can guide researchers and practitioners in the development of efficient and effective fixtures for manufacturing systems.该文献的详细信息和全文内容可能需要通过在线学术数据库或图书馆资源获取。
车床机床夹具类外文文献翻译、中英文翻译、外文翻译
中北大学信息商务学院本科毕业设计英文参考资料题目 Lathes系名专业姓名学号指导教师2016年6 月2 日译文标题车床简介原文标题Lathes作者(Serope kalpakjian)译名卡尔帕基安国籍美国原文出处/原文：LathesLathes are machine tools designed primarily to do turning, facing and boring, Very little turning is done on other types of machine tools, and none can do it with equal facility. Because lathes also can do drilling and reaming, their versatility permits several operations to be done with a single setup of the work piece. Consequently, more lathes of various types are used in manufacturing than any other machine tool.The essential components of a lathe are the bed, headstock assembly, tailstock assembly, and the leads crew and feed rod.The bed is the backbone of a lathe. It usually is made of well normalized or aged gray or nodular cast iron and provides s heavy, rigid frame on which all the other basic components are mounted. Two sets of parallel, longitudinal ways, inner and outer, are contained on the bed, usually on the upper side. Some makers use an inverted V-shape for all four ways, whereas others utilize one inverted V and one flat way in one or both sets, They are precision-machined to assure accuracy of alignment. On most modern lathes the way are surface-hardened to resist wear and abrasion, but precaution should be taken in operating a lathe to assure that the ways are not damaged. Any inaccuracy in them usually means that the accuracy of the entire lathe is destroyed.The headstock is mounted in a foxed position on the inner ways, usually at the left end of the bed. It provides a powered means of rotating the word at various speeds . Essentially, it consists of a hollow spindle, mounted in accurate bearings, and a set of transmission gears-similar to a truck transmission—through which the spindle can be rotated at a number of speeds. Most lathes provide from 8 to 18 speeds, usually in a geometric ratio, and on modern lathes all the speeds can be obtained merely by moving from two to four levers. An increasing trend is to provide a continuously variable speed range through electrical or mechanical drives.Because the accuracy of a lathe is greatly dependent on the spindle, it is of heavyconstruction and mounted in heavy bearings, usually preloaded tapered roller or ball types. The spindle has a hole extending through its length, through which long bar stock can be fed. The size of maximum size of bar stock that can be machined when the material must be fed through spindle.The tailsticd assembly consists, essentially, of three parts. A lower casting fits on the inner ways of the bed and can slide longitudinally thereon, with a means for clamping the entire assembly in any desired location, An upper casting fits on the lower one and can be moved transversely upon it, on some type of keyed ways, to permit aligning the assembly is the tailstock quill. This is a hollow steel cylinder, usually about 51 to 76mm(2to 3 inches) in diameter, that can be moved several inches longitudinally in and out of the upper casting by means of a hand wheel and screw.The size of a lathe is designated by two dimensions. The first is known as the swing. This is the maximum diameter of work that can be rotated on a lathe. It is approximately twice the distance between the line connecting the lathe centers and the nearest point on the ways, The second size dimension is the maximum distance between centers. The swing thus indicates the maximum work piece diameter that can be turned in the lathe, while the distance between centers indicates the maximum length of work piece that can be mounted between centers.Engine lathes are the type most frequently used in manufacturing. They areheavy-duty machine tools with all the components described previously and have power drive for all tool movements except on the compound rest. They commonly range in size from 305 to 610 mm(12 to 24 inches)swing and from 610 to 1219 mm(24 to 48 inches) center distances, but swings up to 1270 mm(50 inches) and center distances up to3658mm(12 feet) are not uncommon. Most have chip pans and a built-in coolant circulating system. Smaller engine lathes-with swings usually not over 330 mm (13 inches ) –also are available in bench type, designed for the bed to be mounted on a bench on a bench or cabinet.Although engine lathes are versatile and very useful, because of the time required for changing and setting tools and for making measurements on the work piece, thy are not suitable for quantity production. Often the actual chip-production tine is less than 30% of the total cycle time. In addition, a skilled machinist is required for all the operations, and such persons are costly and often in short supply. However, much of the operator’s time is consumed by simple, repetitious adjustments and in watching chips being made. Consequently, to reduce or eliminate the amount of skilled labor that is required, turret lathes, screw machines, and other types of semiautomatic and automatic lathes have been highly developed and are widely used in manufacturing.2 Numerical ControlOne of the most fundamental concepts in the area of advanced manufacturing technologies is numerical control (NC). Prior to the advent of NC, all machine tools ere manually operated and controlled. Among the many limitations associated with manual control machine tools, perhaps none is more prominent than the limitation of operator skills. With manual control, the quality of the product is directly related to and limited to the skills of the operator. Numerical control represents the first major step away from human control of machine tools.Numerical control means the control of machine tools and other manufacturing systems through the use of prerecorded, written symbolic instructions. Rather than operating a machine tool, an NC technician writes a program that issues operational instructions to the machine tool. For a machine tool to be numerically controlled, it must be interfaced with a device for accepting and decoding the programmed instructions, known as a reader.Numerical control was developed to overcome the limitation of human operators, and it has done so. Numerical control machines are more accurate than manually operated machines, they can produce parts more uniformly, they are faster, and the long-run tooling costs are lower. The development of NC led to the development of several other innovations in manufacturing technology:Electrical discharge machining,Laser cutting,Electron beam welding.Numerical control has also made machine tools more versatile than their manually operated predecessors. An NC machine tool can automatically produce a wide of parts, each involving an assortment of widely varied and complex machining processes. Numerical control has allowed manufacturers to undertake the production of products that would not have been feasible from an economic perspective using manually controlled machine tolls and processes.Like so many advanced technologies, NC was born in the laboratories of the Massachusetts Institute of Technology. The concept of NC was developed in the early 1950s with funding provided by the U.S. Air Force. In its earliest stages, NC machines were able to made straight cuts efficiently and effectively.However, curved paths were a problem because the machine tool had to be programmed to undertake a series of horizontal and vertical steps to produce a curve. The shorter the straight lines making up the steps, the smoother is the curve, Each line segment in the steps had to be calculated.This problem led to the development in 1959 of the Automatically Programmed Tools (APT) language. This is a special programming language for NC that uses statementssimilar to English language to define the part geometry, describe the cutting tool configuration, and specify the necessary motions. The development of the APT language was a major step forward in the fur ther development from those used today. The machines had hardwired logic circuits. The instructional programs were written on punched paper, which was later to be replaced by magnetic plastic tape. A tape reader was used to interpret the instructions written on the tape for the machine. Together, all of this represented a giant step forward in the control of machine tools. However, there were a number of problems with NC at this point in its development.A major problem was the fragility of the punched paper tape medium. It was common for the paper tape containing the programmed instructions to break or tear during a machining process. This problem was exacerbated by the fact that each successive time a part was produced on a machine tool, the paper tape carrying the programmed instructions had to be rerun through the reader. If it was necessary to produce 100 copies of a given part, it was also necessary to run the paper tape through the reader 100 separate tines. Fragile paper tapes simply could not withstand the rigors of a shop floor environment and this kind of repeated use.This led to the development of a special magnetic plastic tape. Whereas the paper carried the programmed instructions as a series of holes punched in the tape, the plastic tape carried the instructions as a series of magnetic dots. The plastic tape was much stronger than the paper tape, which solved the problem of frequent tearing and breakage. However, it still left two other problems.The most important of these was that it was difficult or impossible to change the instructions entered on the tape. To made even the most minor adjustments in a program of instructions, it was necessary to interrupt machining operations and make a new tape. It was also still necessary to run the tape through the reader as many times as there were parts to be produced. Fortunately, computer technology became a reality and soon solved the problems of NC associated with punched paper and plastic tape.The development of a concept known as direct numerical control (DNC) solved the paper and plastic tape problems associated with numerical control by simply eliminating tape as the medium for carrying the programmed instructions. In direct numerical control, machine tools are tied, via a data transmission link, to a host computer. Programs for operating the machine tools are stored in the host computer and fed to the machine tool an needed via the data transmission linkage. Direct numerical control represented a major step forward over punched tape and plastic tape. However, it is subject to the same limitations as all technologies that depend on a host computer. When the host computer goes down, the machine tools also experience downtime. This problem led to the development of computernumerical control.3 TurningThe engine lathe, one of the oldest metal removal machines, has a number of useful and highly desirable attributes. Today these lathes are used primarily in small shops where smaller quantities rather than large production runs are encountered.Th e engine lathe has been replaced in today’s production shops by a wide variety of automatic lathes such as automatic of single-point tooling for maximum metal removal, and the use of form tools for finish on a par with the fastest processing equipment on the scene today.Tolerances for the engine lathe depend primarily on the skill of the operator. The design engineer must be careful in using tolerances of an experimental part that has been produced on the engine lathe by a skilled operator. In redesigning an experimental part for production, economical tolerances should be used.Turret Lathes Production machining equipment must be evaluated now, more than ever before, this criterion for establishing the production qualification of a specific method, the turret lathe merits a high rating.In designing for low quantities such as 100 or 200 parts, it is most economical to use the turret lathe. In achieving the optimum tolerances possible on the turrets lathe, the designer should strive for a minimum of operations.Automatic Screw Machines Generally, automatic screw machines fall into several categories; single-spindle automatics, multiple-spindle automatics and automatic chucking machines. Originally designed for rapid, automatic production of screws and similar threaded parts, the automatic screw machine has long since exceeded the confines of this narrow field, and today plays a vital role in the mass production of a variety of precision parts. Quantities play an important part in the economy of the parts machined on the automatic screw machine. Quantities less than on the automatic screw machine. The cost of the parts machined can be reduced if the minimum economical lot size is calculated and the proper machine is selected for these quantities.Automatic Tracer Lathes Since surface roughness depends greatly on material turned, tooling , and feeds and speeds employed, minimum tolerances that can be held on automatic tracer lathes are not necessarily the most economical tolerances.In some cases, tolerances of 0.05mm are held in continuous production using but one cut . groove width can be held to 0.125mm on some parts. Bores and single-point finishes can be held to 0.0125mm. On high-production runs where maximum output is desirable, a minimum tolerance of 0.125mm is economical on both diameter and length of turn。
机械加工工艺装备夹具外文文献翻译、中英文翻译、外文翻译
外语文献翻译摘自: 《制造工程与技术（机加工）》（英文版）《Manufacturing Engineering and Technology —Machining 》机械工业出版社 2004年3月第1版 页—564560P美 s. 卡尔帕基安(Serope kalpakjian)s.r 施密德(Steven R.Schmid) 著原文：20.9 MACHINABILITYThe machinability of a material usually defined in terms of four factors:1、Surface finish and integrity of the machined part; 2、Tool life obtained; 3、Force and power requirements; 4、 Chip control.Thus, good machinability good surface finish and integrity, long tool life, and low force And power requirements. As for chip control, long and thin (stringy) cured chips, if not broken up, can severely interfere with the cutting operation by becoming entangled in the cutting zone.Because of the complex nature of cutting operations, it is difficult to establish relationships that quantitatively define the machinability of a material. Inmanufacturing plants, tool life and surface roughness are generally considered to be the most important factors in machinability. Although not used much any more, approximate machinability ratings are available in the example below.20.9.1 Machinability Of SteelsBecause steels are among the most important engineering materials (as noted in Chapter 5), their machinability has been studied extensively. The machinability of steels has been mainly improved by adding lead and sulfur to obtain so-called free-machining steels.Resulfurized and Rephosphorized steels. Sulfur in steels forms manganese sulfide inclusions (second-phase particles), which act as stress raisers in the primaryshear zone. As a result, the chips produced break up easily and are small; this improves machinability. The size, shape, distribution, and concentration of these inclusions significantly influence machinability. Elements such as tellurium and selenium, which are both chemically similar to sulfur, act as inclusion modifiers in resulfurized steels.Phosphorus in steels has two major effects. It strengthens the ferrite, causing increased hardness. Harder steels result in better chip formation and surface finish. Note that soft steels can be difficult to machine, with built-up edge formation and poor surface finish. The second effect is that increased hardness causes the formation of short chips instead of continuous stringy ones, thereby improving machinability.Leaded Steels. A high percentage of lead in steels solidifies at the tip of manganese sulfide inclusions. In non-resulfurized grades of steel, lead takes the form of dispersed fine particles. Lead is insoluble in iron, copper, and aluminum and their alloys. Because of its low shear strength, therefore, lead acts as a solid lubricant (Section 32.11) and is smeared over the tool-chip interface during cutting. This behavior has been verified by the presence of high concentrations of lead on thetool-side face of chips when machining leaded steels.When the temperature is sufficiently high-for instance, at high cutting speeds and feeds (Section 20.6)—the lead melts directly in front of the tool, acting as a liquid lubricant. In addition to this effect, lead lowers the shear stress in the primary shear zone, reducing cutting forces and power consumption. Lead can be used in every grade of steel, such as 10xx, 11xx, 12xx, 41xx, etc. Leaded steels are identified by the letter L between the second and third numerals (for example, 10L45). (Note that in stainless steels, similar use of the letter L means “low carbon,” a condition that improves their corrosion resistance.)However, because lead is a well-known toxin and a pollutant, there are serious environmental concerns about its use in steels (estimated at 4500 tons of lead consumption every year in the production of steels). Consequently, there is a continuing trend toward eliminating the use of lead in steels (lead-free steels). Bismuth and tin are now being investigated as possible substitutes for lead in steels.Calcium-Deoxidized Steels. An important development is calcium-deoxidized steels, in which oxide flakes of calcium silicates (CaSo) are formed. These flakes, in turn, reduce the strength of the secondary shear zone, decreasing tool-chip interfaceand wear. Temperature is correspondingly reduced. Consequently, these steels produce less crater wear, especially at high cutting speeds.Stainless Steels. Austenitic (300 series) steels are generally difficult to machine. Chatter can be s problem, necessitating machine tools with high stiffness. However, ferritic stainless steels (also 300 series) have good machinability. Martensitic (400 series) steels are abrasive, tend to form a built-up edge, and require tool materials with high hot hardness and crater-wear resistance. Precipitation-hardening stainless steels are strong and abrasive, requiring hard and abrasion-resistant tool materials.The Effects of Other Elements in Steels on Machinability. The presence of aluminum and silicon in steels is always harmful because these elements combine with oxygen to form aluminum oxide and silicates, which are hard and abrasive. These compounds increase tool wear and reduce machinability. It is essential to produce and use clean steels.Carbon and manganese have various effects on the machinability of steels, depending on their composition. Plain low-carbon steels (less than 0.15% C) can produce poor surface finish by forming a built-up edge. Cast steels are more abrasive, although their machinability is similar to that of wrought steels. Tool and die steels are very difficult to machine and usually require annealing prior to machining. Machinability of most steels is improved by cold working, which hardens the material and reduces the tendency for built-up edge formation.Other alloying elements, such as nickel, chromium, molybdenum, and vanadium, which improve the properties of steels, generally reduce machinability. The effect of boron is negligible. Gaseous elements such as hydrogen and nitrogen can have particularly detrimental effects on the properties of steel. Oxygen has been shown to have a strong effect on the aspect ratio of the manganese sulfide inclusions; the higher the oxygen content, the lower the aspect ratio and the higher the machinability.In selecting various elements to improve machinability, we should consider the possible detrimental effects of these elements on the properties and strength of the machined part in service. At elevated temperatures, for example, lead causes embrittlement of steels (liquid-metal embrittlement, hot shortness; see Section 1.4.3), although at room temperature it has no effect on mechanical properties.Sulfur can severely reduce the hot workability of steels, because of the formation of iron sulfide, unless sufficient manganese is present to prevent such formation. Atroom temperature, the mechanical properties of resulfurized steels depend on the orientation of the deformed manganese sulfide inclusions (anisotropy). Rephosphorized steels are significantly less ductile, and are produced solely to improve machinability.20.9.2 Machinability of Various Other MetalsAluminum is generally very easy to machine, although the softer grades tend to form a built-up edge, resulting in poor surface finish. High cutting speeds, high rake angles, and high relief angles are recommended. Wrought aluminum alloys with high silicon content and cast aluminum alloys may be abrasive; they require harder tool materials. Dimensional tolerance control may be a problem in machining aluminum, since it has a high thermal coefficient of expansion and a relatively low elastic modulus.Beryllium is similar to cast irons. Because it is more abrasive and toxic, though, it requires machining in a controlled environment.Cast gray irons are generally machinable but are. Free carbides in castings reduce their machinability and cause tool chipping or fracture, necessitating tools with high toughness. Nodular and malleable irons are machinable with hard tool materials.Cobalt-based alloys are abrasive and highly work-hardening. They require sharp, abrasion-resistant tool materials and low feeds and speeds.Wrought copper can be difficult to machine because of built-up edge formation, although cast copper alloys are easy to machine. Brasses are easy to machine, especially with the addition pf lead (leaded free-machining brass). Bronzes are more difficult to machine than brass.Magnesium is very easy to machine, with good surface finish and prolonged tool life. However care should be exercised because of its high rate of oxidation and the danger of fire (the element is pyrophoric).Molybdenum is ductile and work-hardening, so it can produce poor surface finish. Sharp tools are necessary.Nickel-based alloys are work-hardening, abrasive, and strong at high temperatures. Their machinability is similar to that of stainless steels.Tantalum is very work-hardening, ductile, and soft. It produces a poor surfacefinish; tool wear is high.Titanium and its alloys have poor thermal conductivity (indeed, the lowest of all metals), causing significant temperature rise and built-up edge; they can be difficult to machine.Tungsten is brittle, strong, and very abrasive, so its machinability is low,although it greatly improves at elevated temperatures.Zirconium has good machinability. It requires a coolant-type cutting fluid,however, because of the explosion and fire.20.9.3 Machinability of Various MaterialsGraphite is abrasive; it requires hard, abrasion-resistant, sharp tools.Thermoplastics generally have low thermal conductivity, low elastic modulus, and low softening temperature. Consequently, machining them requires tools with positive rake angles (to reduce cutting forces), large relief angles, small depths of cut and feed, relatively high speeds, andproper support of the workpiece. Tools should be sharp.External cooling of the cutting zone may be necessary to keep the chips from becoming “gummy” and sticking to the tools. Cooling can usually be achieved with a jet of air, vapor mist, or water-soluble oils. Residual stresses may develop during machining. To relieve these stresses, machined parts can be annealed for a period of time at temperatures ranging from C ︒80 to C ︒160 (F ︒175to F ︒315), and then cooled slowly and uniformly to room temperature.Thermosetting plastics are brittle and sensitive to thermal gradients duringcutting. Their machinability is generally similar to that of thermoplastics.Because of the fibers present, reinforced plastics are very abrasive and aredifficult to machine. Fiber tearing, pulling, and edge delamination are significant problems; they can lead to severe reduction in the load-carrying capacity of the component. Furthermore, machining of these materials requires careful removal of machining debris to avoid contact with and inhaling of the fibers.The machinability of ceramics has improved steadily with the development of nanoceramics (Section 8.2.5) and with the selection of appropriate processing parameters, such as ductile-regime cutting (Section 22.4.2).Metal-matrix and ceramic-matrix composites can be difficult to machine, depending on the properties of the individual components, i.e., reinforcing or whiskers, as well as the matrix material.20.9.4 Thermally Assisted MachiningMetals and alloys that are difficult to machine at room temperature can be machined more easily at elevated temperatures. In thermally assisted machining (hot machining), the source of heat—a torch, induction coil, high-energy beam (such as laser or electron beam), or plasma arc—is forces, (b) increased tool life, (c) use of inexpensive cutting-tool materials, (d) higher material-removal rates, and (e) reduced tendency for vibration and chatter.It may be difficult to heat and maintain a uniform temperature distribution within the workpiece. Also, the original microstructure of the workpiece may be adversely affected by elevated temperatures. Most applications of hot machining are in the turning of high-strength metals and alloys, although experiments are in progress to machine ceramics such as silicon nitride.SUMMARYMachinability is usually defined in terms of surface finish, tool life, force and power requirements, and chip control. Machinability of materials depends not only on their intrinsic properties and microstructure, but also on proper selection and control of process variables.译文：20.9 可机加工性一种材料的可机加工性通常以四种因素的方式定义：1、分的表面光洁性和表面完整性。
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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。
一种新产品在其他竞争者之前快速进入市场内，是一个能够起到保护、增加市场较高占用额和利润的决定性的因素。
由于对多样性的消费者渴求，已经造成对制造业者需要发展有柔性的制造业的要求，现在产品的一届生产是产品发展中达成一个迅速的大量生产的转机。
一些因素对达成有柔性的制造业的组织能力有影响，其中之一，在生产期间，夹具使用在对哪一个工件进行过生产的机制操作后进入产品之内被装配的个别的部份。
夹具在生产期间要快速、准确、安全地定位工件，使机器制造部份满足设计规格。
现代制造业中准确性促进许多不同的产品以通常的部份为特色达到普遍的部份的可互换性。
夹具的费用占制造业系统的总计费用的10-20〔1。
这些费用不仅包括夹具产品、装配，运转，也包括它们的设计。
因此为了减少夹具与设计费用，有两种方法已经被采用实现这一目标。
一是专注于发展有柔性的夹具系统，例如使用适当地新型材料装夹工件〔2和发展商业模组夹具系统。
然而，有柔性的夹具重要标准是它没有处理设计夹具的困难。
要解决这一个问题，第二个研究方法是发展单一化夹具设计程序的辅助计算机的夹具设计（CAFD）制度，它就是在这文献里面被讨论的研究方法。
第2 节描述主要时期和使用夹具设计程序的需求的广泛多样性。
后来在第 3节研究努力哪一已经在技术的发展之上集中焦点的概观，而且提供用工具工作为了辅助设计程序的个第别时期。
4 节讨论这些努力识别现在CAFD 研究的缝隙，最后报纸藉由为将来的CAFD 研究提出一些潜在的方向总结。
在进行之前，已经有夹具研究的早先讨论值得注意，最近毕和张〔1，Pehlivan 和Summers〔3.毕和张当提供关于CAFD 研究的一些细节的时候，容易在有柔性的夹具系统的发展和Pehlivan 与Summers 之上集中和在夹具设计里面的在数据整合之上重合。
这篇论文的价值是它提供现在CAFD 技术和工具和他们如何提供横跨整个的夹具设计程序的支持的深入讨论和批评。
2. 夹具设计这一个区段概括说明夹具的主要特征，相关夹具设计程序对研究努力不利将会在第3和4 节被分别地检讨和批评。
机床上有一个支持夹紧工件夹具装置〔45.图 1 是一个工件正确地固定在它的夹具体上的典型例子。
螺栓在加工期间，如此支撑夹紧夹具体工件，固定工件位置。
定位系统有自己的辅助单元和连络工件的定位器。
定位组件有一个螺栓，—辅助单元和一个连络工件，而且产生一个定位力量防止螺栓的松动。
制造这样典型地夹具的设计程序有四个阶段：装备设计，夹具设计，元件设计，和确认，例如在图2 中的说明这是适用于Kang et al 的论点的〔6. 在装置规划和加工工件信息，为每个装置分析决定机构的数量要求，完成所有必要的加工操作和适当的定位基准。
工件的手动操作代表一个设置相结合的过程可以执行一个无需改变位置或定位工件操作。
要为产生每种装备一个夹具夹具计划单元设计，和运行确认阶段。
在夹具规划，包含设置生成满足要求的夹具和生成的布局规划，它代表了对这些要求解决方案的第一步。
这种布局计划的细节将建立与夹具的定位和夹紧装置的工件表面接触，加上表面的定位和夹紧点位置。
定位点的数量和位置，必须使工件加工过程中的6 度自由（图3）有足够的的约束7，有各种各样的方便概念定位点布局，如3- 2-1 定位的原则4。
在第三阶段，产生合适的元件设计（即定位和夹紧装置）和夹具随后在验证阶段测试，以确保它满足夹具的设计过程中要求。
因为它们产生和元件设计前，采取设置和夹具计划的核查，这是值得注意的地方。
夹具的要求虽然没有显示Kang et al。
6通常设计夹具阶段可以划分为六类表1。
“公差”的要求与确保有足够“支撑”是最基本的要求同时和保证工件夹具可以物理支持；的定位误差的工件定位准确；同样的“夹紧”的要求集中维护这个精度夹具中工件与受加工的力量；“购买力”的要求与保障夹具代表的值例如在从材料、操作和装配、拆卸成本。
“可用性”的“碰撞检测”要求专注于确保夹具与加工路径、工件、甚至本身不碰撞。
要求与夹具相关工程学有关，包括例如需要确保一个固定以防止不正确特征嵌入一个工件和芯片脱落的误差分析那里的夹具协助去除工件加工的误差。
有很多设计的情况下这些要求是有冲突的。
举个例子一个重夹具在安定方面可能是有利的但是成本由于材料成本的增加和可用性因为体重增加可能会阻碍手工处理效果不好。
这种冲突增加夹具的设计的复杂性并对此需要研究综述CAFD 第3 节。
3.目前CAFD 的方法这部分描述了当前的CAFD 的研究成果重点介绍了在他们支持的四阶段夹具设计的方表式。
2 总结研究成果提供了一个基于设计阶段他们的支持该夹具的要求他们寻求地址要求是写给很大程度上的深度而普通文本程度在自然界的深度较小以及他们潜在的技术对主要的基础。
第 3.1-3.4 部分分别描述了不同方案支持设置规划、夹具规划、元件设计、验证。
此外第3.5 节讨论了对于CAFD 代表夹具的信息研究成果。
3.1 设置规划设置规划涉及识别加工方法一种个别的装备定义能在没有必须用手改变工件的位置或定方位的工件上被以机器制造的特征。
其后，设计程序的剩余阶段把重心集中在为保护工件的每种装备发展夹具。
从夹具的观点关键输出安装规划阶段是识别各类要求设置、定位基准例如主要的表面将用于工件在夹具定位。
在关键任务设置规划或分组加工的功能可以在一个单一工件设置。
加工特征量可以定义为被切削工具典型的例子包括孔、槽、表面和内表面8。
这些特征聚类成独立的设置是依赖于许多因素包括公差之间的依赖关系的能力特点机床将被用来创造特点、方向刀具的加工方法和特征优先顺序和一批技术已经开发支持设置规划。
虽然基于矩阵的技术和神经网络也被使用，但是图论和启发式推理是最普遍的技术用于支持设置规划。
3.1.1 满足要求的设置规划使用图论方法确定和代表机构已经是一个特别常用的方法。
9 - 11。