制造系统设计-毕业论文外文翻译.docx

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1、Production Systems DesignThe design of a production system starts with the design of the product to be manufactured. Figure 6. 1 describes a typical sequence of steps starting with a product design concept that culminates in a final product design for manufacture. Product engineers are those individ

2、uals in a manufacturing organization most familiar with the function of a product.and the customers changing needs relative to that product.Figure 6. 1 The design manufacturing Interface.Arts-Way Manufacturing is a manufacturer of farm machinery in Armstrong, Iowa. As soon as the beet harvesting sea

3、son comes to an end at the end of summer, Arts Way product engineering and marketing personnel evaluate their most recent harvester design successes and any unique conditions or problems that affected the performance of their equipment. Theres nothing like a harvest to bring to light the strengths a

4、nd weaknesses of a harvester design. As soon as the harvester performance information is collected and evaluated and customer and dealer Inputs have been reviewed. it is likely that design improvements and related engineering tests will begin immediately for an improved harvester product to be avail

5、able for next summer. The more mature is the design. the fewer design changes that will likely be developed during the next improvement cycle. This is the kind of interest a small manufacturer has in its products that no amount of central planning in the Soviet economy could have ever successfully d

6、uplicated, The Russians should talk to the people in Armstrong, Iuwa, and watch them analyze, design. And make harvesters if they want to learn how to make farm machinery the American way. If all goes well, the nine months between harvests will provide sufficient time to make the desired engineering

7、 tests,and to add design improvements needed before the release of material requisitions, so that next years improved harvesters will he ready in time, It is not uncommon that, as the time approaches to make material releases for the improved designs, product engineering will beg for more time to ru

8、n one more test. A saying in the.Architectural and Engineering (A&E) business often applies in this situation: Sooner or later you have to shoot the engineer and build the building. The best compromise often is for some product improvements to wait for next years product design. It will be noted in

9、reviewing Figure 6. 1 that much of the shove effort lies in interactions between product engineering, manufacturing engineering, and production. The manufacture of a new design is always a process of discovery. In Frederick W. Taylors days, the new design for a machine element might be a line drawn

10、on the molding shop floor, which the master mold maker would then use to produce a stronger machine element for the next test of.the machine. When the stronger part was molded. It would be Installed on the machine, the machine would run for some seconds, minuites, or hours. And would fail again, oft

11、en in a different place, and the process would be repeated. Ultimately, a machine design would evolve that would produce a machine that would run all the time. These machines were sold to customers. With todays perfected engineering knowledge it is much more likely that the design will perform as de

12、signed, if not the first time. with far fewer prototype redesigns. Expert systems and Taguchi methods, both to be discussed later in this text. Provide the means for doing a much better job today of optimizing both the product design in its underlying function and identifying the best means of manuf

13、acture for producing a highquality. Reliable, and cost effective product.Computer-Aided Drafting and design (CADD)Whereas design may have been accomplished with a stick on the molding shop floor in Tailors time, CAD/CAE/CAM (computer-aided design, computer-aided engineering ,computer-aided manufactu

14、ring) is becoming the preferred means today for producing designs. Most people think of CADD (computer-aided drafting and design) as simply electronic drafting, which greatly understates the computer revolution associated with the tasks implied in Figure 6. 1. The following excerpt from a paper by F

15、loyd concerning the use of CADD in the automotive industry provides some insight as to the overall comprehensiveness of the computer revolution in engineered product design today.CAD/CAE/CAM for the Automotive IndustryBryan FloydExecutive ManagerMechanical Design/Engigneering/Manunfacturing. Intergr

16、aph CorpFully integrated design, engineering, and manufacturing. Automotive manufacturing is a complex business that integrates the efforts of many departments and disciplines. Tools that promote the integration of design, engineering, and manufacturing processes yield the greatest productivity bene

17、fits. Intergraph offers automakers the master model Concept asingle Intelligent product definition that drives all aspects of development, from concept through production. Intergraphs tightly integrated systems eliminate intermediate transfer or re-entry of data between design. Analysis, and manufac

18、turing phases. Additionally, all product development capabilities are simultaneously accessible through a single user interface, allowing engineers to combine functions, as needed, without changing environments, Conceptual design and styling. Intergraph systems provide advanced tools for conceptual

19、design and automotive styling, with high-performance graphics for concept visualization and communication. I/DESIGN. Intergraphs Industrial design system. Includes high precision modeling and photo realistic rendering capabilities that aid in developing a functional, ergonomic, and aesthetic design.

20、 Precision geometric modeling. Automotive engineers require CAD/CAE/CAM modeling that ran precisely describe complex surfaces and completely model Intricate assemblies. Intergraph meets these demands with the Engineering Modeling System (I/EMS). which isbased on highly accurate non-uniform rational

21、B-spline (NURBS) mathematics. Intergraph is distinguished from other CAD/CAE/CAM vendors by offering advanced geometric modeling as a foundation for analysis and manufacturing.Solid modeling. When designing an automobile, engineers must know Critical geometric properties including masses and displac

22、ement volumes that are only available with solid modeling techniques. Property calculations, such as volume, cross sectional area. radius of gyration, moments of Inertia. mass density, and others are included in I/EMS as standard functions supporting the sofwares solid modeling capability.Assembly d

23、esign and configuration management. Automotive development depends on a wealth of application data for thousands of components. Intergraph provides Product Data Manager (I/PDM) as a complete system for controlling and managing access to the product database. Without regard for physical storage locat

24、ions, file names. or operating system platforms. engineers can locate and retrieve data from any location on a heterogeneous network. Structural analysis. By simulating performance characteristics of designs before products are built, automakers complete designs in less time and reduce overdesign. F

25、inite element analysis techniques help ensure compliance with performance standards and reduce the risk of failure in the field. These benefits are achieved with automatic and interactive meshing.Hadaptive refinement technology and integrated solver，and full postprocessing functions,all available wi

26、th lntergraphs Finite Element Modeling (I/FEM system.Plastics design and analysis. When Integrated Into the mechanical design process, plastics design and analysis functions can improve the quality of plastic components, increase yield, and reduce manufacturing cycle times. Plastics engineers can pr

27、edict plastics behavior under molding conditions using the injection Flow Analysis (I/FLO) package. The FLOW model can then be used in conjunction with the Plastics Cooling Analysis (l/COOL) software to analyze heat transfer in cooling circuit layouts. By analyzing temperature distribution .Engineer

28、s can reduce distortion and cooling times for infected plastic parts.Mechanism and kinematic analysis. Engineers designing mechanical systems must determine how forces and motions vary over time to achieve performance goals and eliminate part to part Interference. With Mechanical Systems Modeler (I/

29、MSM). engineers analyze motions and part to part interactions and conduct kinematic and kinetostatic analyses with the built in solution program. To conduct static equilibrium and dynamic analyses, engineers have access to I/MSMs modeling and post processing functions and direct Interface to third p

30、arty programs, including ADAMS and DADS.Manufacturing capabilities. The diversity of processes required in automotive production demands a versatile set of manufacturing tools. Intergraph manufacturing solutions include the Industrys broadest range of NC programming and fabrication tools, I/NC. Inte

31、rgraph s off line programming environment. Supports machining capabilities for multiple-axis milling, thermal cutting, wire EDM, turret punching, and turning. Integrated fabrication software addresses flat pattern development and nesting processes.Integrated designand manufacturing. To minimize prod

32、uction lead times, Increase equipment and material yields, and reduce errors. Intergraph offers automakers complete CAD-to-CAM integration. M8nufacturing processes are developed directly from the design model, An intelligent database structure automatically maintains the relationships between compon

33、ent geometries, toolpaths, machine and tool characteristics, and other variables to greatly reduce the input required to generate, maintain, and verify manufacturing data.Electronic design and analysis. The Increasing electronic content of automobiles demands coordination of electronic and mechanica

34、l design processes. To satisfy this demand Intergraph provides a full suite of Integrated electronics design applications. The Design Engineer series of products works in conjunction with mechanical design applications topromote a concurrent engineering environmentFacilities mauagement. To operate a

35、t peak efficiency. manufacturing facilities must optimize spatial and functional relationships. Designers can avoid trial-and-error space planning and factory layout with Project Planner, a software package that models facilities, simulates manufacturing scenarios, and determines an optimal lit with

36、in the building envelope.Computer Aided Process Planning.According to the Tool & Manufacturing Engineers Handbook, process planning is the systematic determination of the methods by which a product is to be manufactured economically and documentation. Processes, machines, tools, operations, and sequ

37、ences must be selected. Such factors as feeds, speeds, tolerances, dimensions, and costs must be calculated. Finally, documents in the form of setup instructions, work instructions, illustrated process sheets, and routings must be prepared. Process planning is an intermediate stage between designing

38、 and manufacturing the product. But how well does it bridge design and manufacturing?Most manufacturing engineers would agree that, if ten different planners were asked to develop a process plan for the same part, they would probably come up with ten different plans. Obviously, and, in fact, there i

39、s no guarantee that any one of them will constitute the optimum method for manufacturing the part.What may be even more disturbing is that a process plan developed for a part during a current manufacturing program may be quote different form the plan developed for the same or similar part during a p

40、revious manufacturing program and it may never be used again for the same or similar part. That represents a lot of wasted effort and produces a great many inconsistencies in routing, tooling, labor requirements, costing, and possibly even purchase requirements. Of course, process plans should not n

41、ecessarily remain static. As lot sizes change and new technology, equipment, and processes become available, the most effective way to manufacture a particular part also changes, and those changes should be reflected in current process plans released to the shop.A planner must manage and retrieve a

42、great deal of data and many documents, including established standards, mach-inability data, machine specifications, tooling inventories, stock availability, and existing process plans. This is primarily an information-handling job, and the computer is an ideal companion.There is anther advantage to

43、 using computers to help with process planning. Because the task involves many interrelated activities, determining the optimum plan requires many-iterations. Since computer can readily perform vast numbers of comparisons, many more alternative plans can readily perform vast numbers of comparisons,

44、many more alternative plans can be explored than would be possible manually.A third advantage in the use of computer-aided process planning is uniformity.Several specific benefits can be expected from the adoption of computer-aided process-planning techniques:l Reduced clerical effort in preparation

45、 of instructions.l Fewer calculation errors due to human error.l Fewer oversights in logic or instructions because of the prompting capability available with interactive computer programs.l Immediate access to up-to-data information from a central database.l Consistent information, because every pla

46、nner accesses the same database.l Faster response to changes requested by engineering of other operating departments.l Automatic use of the latest revision of a part drawing.l More-detailed, more-uniform process-plan statements produced by word-processing techniques.l More-effective use of inventori

47、es of tools, gages and fixtures and a concomitant reduction in the variety of those items.l Better communication with shop personnel because plans can be more specifically tailored to a particular task and presented in unambiguous, proven language.l Better information for production planning, includ

48、ing cutter-life, forecasting, materials-requirements planning, scheduling, and inventory control.制造系统设计制造系统设计开始于产品制造的设计，图6.1介绍的是一项产品从概念设计到最后完成产品的典型的次序步骤。产品工程师是那些在产品制造业中最熟悉产品功能和客户的不同需求的人。 图6.1 Art-Way农机制造业厂商在啊姆斯特朗、爱荷华地区。在收获季节即将结束时，Art-Way 的设计人员就会衡量收割机设计的成功之处，械的工作条件，以及特殊情况影响了机械运行的问题，没有什么可以象收割一样来揭示收割机的

49、优点和不足了。尽快的收集收割机的工作资料信息和做出的评估以及经销商和客户资金的投入。这样，设计的改善和相关的动力改进将会马上为了明年的更新进的收割机进行测试和生产。比较成熟的设计将会在以后的设计周期减少改进。这种小型厂商的利益,没有自己产品的金额,在中央规划 苏联经济能不断成功复制。俄国人效仿啊姆斯特朗、爱荷华人，看他门农机的设计和分析去制造走自己的美国之路。如果一切顺利，在丰收季节之间将有足够的9个月时间去做工程调整，补充，设计改进，以及物资调用。这样明年的新收割机就会准备好。工程上乞求多做实验是很平常的。在建筑和工程上有句话：“Sooner or later you have to shoot the engineer and build the building。”最好的折衷往往是一些产品的改进等待明年的产品设计回顾图6.1上述办法在产品工程、制造业工程学和生产之间的相互作用这种方式有着很大的帮助。一个新的制造设计总是体现一个发现的过程。在Frederick W.Taylor