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This work currently, is In essence, developing fixture design methodology needs to implemented by a typical designer-centered pattern, that is, all clear two crucial problems: how to represent fixture design knowl- fixture design related work is heavily dependant on the experience edge in a computer and how to implement the problem solving and knowledge of fixture designer. This situation hampers the procedure. Thus, new intelligent or automatic designer to a complete fixture design solution, particularly, fixture technologies on synthesizing traditional geometric design tools, configuration design in an interactive environment .
In most design knowledge, and past design cases have attracted much of these methods, design knowledge is modeled as a set of interest in both academic institutions and industries. Then, during the interactive fixture design over past decades in this field have resulted in numerous computer process, the design solution would be concluded by a series of aided fixture design CAFD applications using various intelligent questioning—answering actions based on these rules.
But as a typical experienced et al. That is why we proposed et al. Multi- Boyle, Divide fixture design Combination of the search level CBRs, from rough indexing, solution configuration to physical et al. Each time, after library and fixture unit library one CBR process completes case indexing and retrieval, the system Sun, Using MOP Memory Cases matching according to will present the designer with a selection of cases for a detailed de- et al.
Generating optimal fixture configuration layouts tree for reasoning procedure have an obvious impact on the design efficiency and the quality of the result. Furthermore, the interactive The research of generating optimal fixture configuration lay- mode also makes the reasoning procedure very boring. These layouts specify the optimum positions where the fix- so much complicated domain knowledge system as the expert ture should contact the workpiece being machined.
The main ideas system.
It is mainly concerned on how to create a new solution are similar in these typical fixture layout optimization research by imitating past cases, based on the assumption that similar articles as Fig. The first step is the application of the machin- workpiece will have a similar fixture design solution. So first, it ing process analysis method to predict the machining forces ex- focuses on structuralizing fixture design cases and to emphasize erted on the workpiece. This analysis is typically carried out for some crucial data which will be the focus in measuring similarities.
The second step is the deformation anal- best similar design case according to case comparison. The CBR ysis of the fixture-workpiece system, utilizing the pre-determined technique gives the possibility to avoid time-consuming and load cases. Typically deformation analysis is based on the finite expensive experiments and is able to propose a good starting point element method FEM.
The loads and the shape of the machined for the detailed design physical form without many complicated surface are calculated, and hence, the deformation of workpiece, calculations. Table 2 gives a comparison among some CBR methods under a given locating and clamping scheme, will be analyzed as in the past decade. In general, if consid- Two techniques remain necessary and crucial in CBR.
One is ering the clamping and machining forces over the entire machining for an efficient method to refine, model and utilize fixture design process, by simulating the dynamic machining process, the analy- domain knowledge fixture design cases , and the other is for an sis on workpiece deformation will be more accurate [54,55], with effective technical system which can assist the fixture designer a cost of time-consuming computation.
Finally, it will employ an not only by simplifying the design process, but also by generating optimization process GA is mostly used to search for a potential design ideas. For example, Chen  used a case template to mation [56,57]. However, there are few deformable while the tools and fixtures are rigid.
So one limitation guidelines on defining and choosing appropriate attributes. Even though by current design case and use these attributes as a vector to compute considering more relevant factors, e. Thus, it results in a demand for systemizing process information, some performance criteria ease of loading fixture design domain knowledge to clarify the design requirement unloading, cost and rate of production , in the design process [44, in CAFD.
Therefore, Boyle [48,49] developed a methodology to 45], fixture unit information also is a high level concept that only classify fixture design information into two libraries: conceptual specifies its basic type and the nature of its components. Currently, design information and fixture unit information.
One interesting method is using the required height as the criti- The fixture design domain knowledge representation has a cal dimension for fixture unit generation, then to complete the de- crucial impact on the CBR procedure. Actually, a single CBR system tailed fixture shape. Particularly, this method is useful for modular using attribute similarity often has not a good performance on fixture unit design where a fixture unit is usually assembled with accurate results.
Sometimes, the attributes which the designer several existing modular fixture components. So the fixture height determined this time do not fit the next time for case indexing, or a can play a crucial role on searching potential elements to assemble. Typical FEM based fixture design solution analysis framework . In this field, the stability of the workpiece-fixture system, par- ticularly, the deformation and accuracy of the system, always attracts most of the attention.
Research on the stability of the fixture-workpiece system, can provide a mechanism for the defor- mation and error chain in the workpiece-fixture system which will guide the user to choose perfect fixtures, adjust suitable fixturing forces and fixture positions to generate adequate contact forces to keep the workpiece in an accurate position during machining. By contrast, due to the fact that most research focuses on machining fixtures where there is only one workpiece, seldom does research put attention on the degree of freedom and geometric constraints of whole system, even though this problem also is important in as- sembly related fixturing situations.
Typical research on the stability of a workpiece-fixture system needs to model workpiece boundary conditions and applied loads during a machining process, before the analysis on the deformation of a workpiece, as the work by Amaral et al. However, they only considered the positions of locators and clamps, and did not consider the deformation of fixtures in this process. The tolerances are defined based on surface sample points, and the workpiece-fixture system is assumed to be rigid.
This kind of workpiece-fixture system for fixtures of rigid bodies and of point Fig. Overview of fixture verification system [62—65]. However, in machining, particularly, in precision and ultra- 3. So in the analysis and numerical simulation pro- achieved tolerance, the deformation and stability of fixture- cess, the stiffness of fixtures should be considered, and the contact workpiece system, and fixturing accessibility, etc.
Fixture curate. Ratchev et al. Verification of a fixture design solu- to represent the point contact between the fixture and workpiece. Assuming a case of only single a manufacturing system; the design solution needs to be verified workpiece-fixture contact, Satyanarayana  have presented as practicable for the whole manufacturing system. Verification or a comparative analysis of the different boundary conditions — monitoring is also needed in the use of a fixture system to justify contact elements nodal and surface-to-surface , nodal boundary whether the system is in a good condition.
As the Fig.
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Un- a framework. Conclusions and future research sure distribution at the contact region in a workpiece-fixture system. Thus, this can help the designer very much in the detailed Recent achievements in the development of computer aided design of a fixture including its shape, material, etc. However, current design and automation theories and 3. Deformation and error analysis of workpiece-fixture system technologies are still not mature. Most current commercialized fixture design tools in manufacturing are traditional geometric- Fixture positioning error has a direct impact on the machining based, for instance, the tooling and fixture design functions in some errors of a workpiece.
In this field, two problems have usually been CAD systems, e. They only provide engineers with a fixture component library of errors on the locators and another is its inverse problem that or simple modules to do fixture design manually based on some involves establishing bounds on the errors of the locators to ensure extended functions of commercial CAD software. Fixture design that the limits specified by geometric tolerances at a feature are still continues to be a major bottleneck in the promotion of current not violated.
So the essential problem is how to represent the manufacturing, though numerous innovative CAFD techniques relationship between the machining error, fixturing error and the have been proposed. Those techniques also need time to be tested deformation of the workpiece-fixture system.
Therefore, several the workpiece datum geometric errors can result in a localization research aspects are promising and challenging. Fixture positioning error or fixel error, by 4. To develop intelligent techniques for computer aided fixture M. Wang comes mainly from three sources. But the real performance of a computerized in the geometric shape of the locator, such as profile tolerance fixture design system is rooted in a powerful ability of the sys- specified for a spherical locator.
For instance, an increasing research interest is using 3 The third source is related to geometric variations that may various meta-heuristic methods to obtain optimal fixture layout exist in the physical datum features of the workpiece. The datum solutions [58—61], which often requires much precise calcula- geometric variations will have an equivalent result of fixel errors in tions in geometry and mechanics. Actually, computer supported the reference frame embedded in the workpiece body.
The primary intelligent algorithms can have a better performance on this objective of a fixturing scheme is to reduce the manufacturing error kind of work. Meanwhile, deploying a multi-sensor network into as related to the three types of fixel errors that are essentially a workpiece-fixture system and using online intelligent control caused by the positional and geometric variability of the locators techniques can adjust fixturing contacts and forces adaptively in and the geometric variability of the workpiece itself.
That is an important reason for the rapid progress of tion and orientation of datum references. For a workpiece, this intelligent techniques on fixture design applications over the past deviation must be within the limits allowed by the geometric years. Various methods on controlling the manufac- Furthermore, recent achievements on some new knowledge- turing errors have been suggested, for instance, 1 using stiffness related techniques, such as knowledge modeling, data mining, ma- optimized machining fixtures and configuration layout to ensure chine learning, and so on, indicate a more promising and fruitful the tolerance limit specified for the machined part surface ; future for the development of advanced computer aided fixture de- 2 during the manufacturing process, clamping forces of active sign.
In many manufacturing companies, the technical knowledge fixtures can be adjusted according to the FEA analysis result to of experienced fixture designers, a huge amount of technical files compensate for machining errors , or 3 adjust suitable clamp and many good design cases are a very valuable resource for fixture forces to generate adequate contact forces and pressure distribu- design. Using new technologies in the knowledge engineering field tion at the contact region to keep the workpiece in position during to refine, model and utilize fixture design domain knowledge as an machining .
For example, some interesting progress eral basic sources of error which can lead to improper results: on using XML technology as a fixture knowledge representation 1 poor input data due to the lack of information about the pro- tool to support case-based reasoning in the fixture design process cess, 2 unreasonable simplifications, idealization and assump- is attractive, despite the reality that it need more effort on the sys- tions of the manufacturing process, 3 improper modeling of the temization of intelligent techniques in fixture design [47,50].
Integrated fixture design system for manufacturing ciated with re-mapping. Besides those sources, in the research of the relationship between machining error and fixture positioning In essence, fixture design only is a partial process in manufac- error, some assumptions on modeling the workpiece-fixture sys- turing, and it should obey to the total objective of workpiece man- tem also can affect the validity of the results.
For instance, assum- ufacturing requirements which often are related with production ing that the workpiece-fixture system is a rigid body [76,70], and resources, equipment, cost and machining processes, etc. There- the workpiece-fixture contact as a theoretical non-friction point fore, it is necessary to put the fixture design task into an overall contact . Managing to achieve quality.
McGraw Hill: Maidenhead; Advanced computer-aided fixture design.
Advanced fixture design for fms. Future  Cecil J. Computer-aided fixture design—a review and future trends. Interna- tional Journal of Advanced Manufacturing Technology ;18 11 —3. Reconfigurable fixtures for automotive integration of fixture systems with other manufacturing systems. In: Dashchenko AI, editor. Particularly, view the fixture design as one node in a whole chain Reconfigurable manufacturing systems and transformable factories.
Berlin: Springer Heidelberg; Assembly fixture fault diagnosis using designated component of fixture design result on the cutting center and machining analysis. Journal of Manufacturing Science and Engineering ; 2 : toolpath, and meanwhile, we also may find a necessary redesign — Instrumented fixtures for on-line correction of welding paths. Tools for simulation based Another important research is on the integration of various fixture design to reduce deformation in advanced fusion welding.
In: The 1st techniques directly used in computer aided fixture design. As International conference on intelligent robotics and applications. Part II.
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Principle and simulation of fixture configuration design different considerations, such as tolerance configuration, stiffness for sheet metal assembly with laser welding. Part 1: finite element modeling configuration, machining process, etc. Applied Mechanics and Materials Volumes Main Theme:. Mechanical Engineering, Materials and Energy. Edited by:. Grace Chang. Online since:. December Add to Cart. Cited by. Related Articles. Paper Title Pages. Abstract: In order to solve the deformation of thin-walled parts when fixed by fixtures in the environment of examination, transport, welding, assembly and demonstration, the paper is based on automatic planning approach of main champing points in Rapid Fixture Design System and mainly focuses on auto-planning auxiliary clamping points of thin-walled parts in Rapid Fixture Design System and represents the layout of auxiliary clamping points to deal with the problem of easy deformation of thin-wall parts when under small stress environment, which establishes automatic planning approach of RP.
Finally, the paper gives an example to verify the effectiveness of the approach. Achieve the goal of designing rapid fixture automatically, fast and efficiently and enhance the capacity of enterprises responding quickly to dynamic changes in the market. Abstract: Optimal fixture involves fixture layout and clamping force determination.
It is critical to ensure the machining accuracy of workpiece. In this paper, the clamping process is analyzed with the consideration of cutting forces and frictions using the finite element method. Then the fixture layout and clamping force are optimized by minimizing the workpiece deformation via a Genetic Algorithm GA. Subsequently, linear programming method is used to estimate the stability of workpiece. It is shown through an example that the proposed method is proved to be efficient.
The optimization result is not only far superior to the experiential one, but also the total optimization time can be reduced significantly. Sign up for new issue notifications. An automated fixture setup design system is developed where when fixturing surfaces and points are described allowing modular fixture components to get automatically select for generating fixture units and placed into position with satisfying assembled conditions. In past, various knowledge based system have been developed to implement CAFD in practice.
Advanced Computer-Aided Fixture Design - Semantic Scholar
In this paper, to obtain an acceptable automated machining fixture design, a case-based reasoning method with developed retrieval system is proposed. Visual Basic VB programming language is used in integrating with SolidWorks API Application programming interface module for better retrieval procedure reducing computational time. These properties are incorporated in numerical simulation to determine the best fit for practical use.
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