外文翻译--国内外轿车覆盖件冲压模具设计概况

Domestic and foreign car coverage Die Design Overview A.S. Pouzada, E.C. Ferreira and A.J. Pontes Abstract : In introducing the current domestic car stamping die design and manufacture of the foundation, expounded foreign auto company cars panel particular panel of the stamping process and die design status application of new technologies . Key words : mechanical manufacturing； Car panel； Stamping technology； Mold Design 1 Introduction In recent years, Chinas car market has developed very rapidly in 2002 in car sales more than one million on the basis of in 2003 to 2 million people relations forward, reaching 1.97 million. However, in the car heat rapidly warming, had to face the embarrassment of this reality-market best-selling vehicle for the majority of people must be directly imported from abroad. As domestic car cover mold design and manufacturing capability on the whole is relatively weak, in order to produce these models, each company had to spend hundreds of millions or hundreds of billion of overseas procurement die. People with foreign automobile companies, because the relatively small scale of production, This has resulted in motorcycle smoothing wood into the mold much higher than foreign cars, This is also produced cars along with high w ood manufacturing into one of the main reasons. 2 Domestic car coverage Die development capability Major car manufacturers to Die : Die Manufacturing Co. Ltd. of FAW, Dongfeng Motor Die Works, Tianjin Automobile Die Company, CAC Integration Technology Co., Ltd Nanjing mold equipment, Shanghai Auto Body 1000 margin Die Company. Most people as a domestic car production and sales of commercial-vehicle population of Shanghai Limited, also has its own mold design and manufacturing departments (TMM Division). Currently, Although domestic Die in Car cover the mold design and manufacturing has a small capacity, auto plants can undertake some development projects die, but for a very high surface accuracy and surface quality requirements of the outside panel. It is especially the high-grade cars outside panel, auto plants rarely die by the will of such domestic development. Shanghai Public Motors Limited in order to reduce vehicle production costs, but also to increase the companys core technical competencies, Since the beginning of 2001, set foot in the car stamping die design and manufacturing fields. 2001 -2002 completed POLO cars manually presses the production line 10 Die simple parts , the companys quality assurance department as well and put into production. Beginning in 2002, the type of people to the complex, automation, 6000kN the design and manufacture of automatic production line POLO cars tyres. Die Block (dimensions of the parts, deep drawing deep, complex shape) in 2003, in order to further enhance the design and manufacture of mold ability and level We get involved in the Multi-Position 20000kN Press and 10000kN automatic production line of die design. Shanghai over the past number of people in many public spaces 20000kN Press on the use of the mold, all u need to progress, Die domestic business still lacks the ability to design and manufacture the mold. To this end, we chose POLO Car column plate mold design. 20000kN Multi-Position Press is the worlds most advanced presses, integration, a very high degree of automation. Of course, this right mold design requirements also increased accordingly. Parts Feeding height, distance, location manipulator strict requirements ensure that the manipulator in the course of the campaign and die without interference, so the mold design for space on a small lot. In considering many factors, we finally completed the whole mold design, CAD state assembly as shown in figure 1. In addition, we have completed the POLO cars 10000kN automatic production line of the rear wheel cover mold design, In last years build on that. These successful completion of the Shanghai marks the number of people die design capability has reached advanced domestic level. thus for the future of Shanghai people die Domestic car lay a solid foundation. Nevertheless, with the international advanced level, the more people there are still gaps, For example, in the car outside cover mold design or from the air. Die in Car, the most difficult of the outer covering die design, mainly in the following two aspects : (1)Overcome by the resilience of parts surface deviations Breakdown, wrinkling, Rebound car is stamping process of forming the main shortcomings, as car outside panel dimensions. deep drawing shallow, plastic deformation low level generally will not crack, Resilience as a result of such parts on the manufacturing process and the main problems, it will seriously affect the parts with the mutual relations. Finite element simulation software in the stamping die design universal application, has been able to accurately predict rupture and wrinkle-free. thus contribute to the design of appropriate auxiliary surfaces to improve the process of drawing materials flow, improve parts forming ft. However, to date) unknown. Most of the finite element software can not be accurately forecast Stamping Die them removed from the rebound after deformation. Therefore, the external panel dealing with the resilience of the major changes to rely on the experience of the die face, stamping parts are forming over, to offset rebound led to the deformation. (2)Stamping the pick-up As foreign coverage (eg front cover plate, the roof and fender panels) are subject to complex flanging plastic or anticipated beading crafts, This makes the design of the mold structure, we must consider the ram after forming the pick-up, the current people are relying on more complex Wedge institutional linkages to achieve some of the work to mold parts his resignation to achieve to enable them to pieces. The resulting mold of the entire structure is very complicated. 3 Foreign coverage Die Design Currently, foreigners Motors Corporation in order to reduce mold development and manufacturing costs, shorten production cycles, In addition to cars outside panel of people out of the car Stamping Die Mold were left to professional companies (such as Fontana Pietro.Kuka.Laepple.Schuler Cartec.Ogi-ha la-Fuji Techniaca etc.) to design and manufacture, these companies have strong development capabilities, and in some parts of the manufacturing mold with unique advantages. But as auto plants, taking into account the development of new models in the process of confidentiality, such as the right-wing boards, suitcase covers, doors, side-Wai, the roof front cover and other sensitive parts of the die, die by their own manufacturing sector to design and manufacture. 3.1 Software Environment Stamping die design, in addition to the need for CAD software, also large-scale application of the finite element simulation software If AutoForm.PamStamp. DynaForm. Indeed, aided design stamping process. Below, AutoForm as an example to show how the use of CAE software design process of drawing surfaces. AutoForm is supplied by the Swiss Development professional rapid simulation of sheet metal forming software can be used in sheet, welded plate stamping, such as Hydroforming process simulation, with different functional modules, can also be used for single-step stamping parts and the simulation of forming processes of drawing surfaces (Addendum) Design . Car stampings, About two-thirds of the use of AutoForm Diedesigner Module Module Design A ddendum the module under specified by the designer or by the software automatically generate pressure-ring face and and the process of multi-added section of the line (Profile), to produce rapid-added process, Drawing for the simulation process, as shown in Figure 2. V-ring face and Profile parameter can be the adjustment. This rapid design is based on surface Addendum Construction of the rough, curved surface film itself, and between the curved surface of the film is not very continuous fairing, Despite this surface is not used directly to the mold surface machining. But the simulation accuracy is not affected people. According to the simulation results. designers can easily add-on technology adjustment until simulation results meet design requirements. Finally, will Blankholder circle Profile Addendum to surface and neutral data format output IGS or VDA, CAD software for surface reconstruction and digital-analog integrated products, will be able to be machined can use the drawing process a few Die Mold. Stamping Process traditional design methods : First, on the basis of experience, the use of CAD technology to add noodles. Secondly, CAD will be transmitted to the model number of AutoForm software such as CAE deep drawing process simulation； According to the simulation results. in CAD add-on process adjustments and a few new CAD - CAE pass to start new simulation, Until meet the requirements for competition. This is one from CAD to CAE to return to the CAD kept in the process. Because each of the CAD surface structure than in AutoForm are complex, therefore, The whole process will have to spend much more time. And the new method of stamping process in the design stage, Diedesigner Module used in AutoForm software design and adjust the deep drawing process surfaces with the traditional design methods, we will be able to greatly improve the efficiency of design. A AutoForm is due to the rapid simulation software in a relatively short time stamping parts of the complicated process of forming the evaluation of membrane modules used to model discrete geometry, bound to reduce the simulation accuracy, therefore, Some car companies prior to the start of mold design will use high-precision simulation of the CAE software, Germany on the number of people using the software Indeed, Drawing on procedures for the simulation again (Indeed calculation software is based on the thickness of the shell element. to be more accurate results, However, the calculation of time spent AutoForm is usually several times that of the 10, The software is applicable to the ultimate test), Drawing all must pass Indeed Process simulation and validation to be feasible, in order for mold design. Mold design complete, the combination of drawings through the bubble acceptance model (Figure 3) different procedures with different colors of the lines marking the bubble model, the so intuitive and clear. Technology should also be organized, including designers, project planning, mold testing, Die operators and other stakeholders to discuss acceptance. For the stamping process difficult to solve the problem of forming, product development should also be invited to discuss personnel, look for changes in product design possibilities. 3.2 Rebound amendment response The former is known, the rebound was cars outside panel forming process of the main questions are covered plate before example, conduct detailed analysis. Usually panel of the rebound following two categories : Large flat surface caused by the elastic response of buckling or collapse, as illustrated in figure 4, Part C Click below, dotted said parts removed from the mold and rebound occurred after the position. In such cases, the design process is not normally be considered. Technology products in a few die-face with some of the data from the product development departments of consistent data, and for die manufacturing. To tryout, and the specimens were seized compared with measurements, according to the deviation of drawing surface model amendment. If designers to control such problems have very rich experience, can be estimated in advance surface elastic recovery and the direction of offset, and will reverse its superposition of several product-development, Rebound consider seeking deformation of the surface of deep drawing process, the calculation process requires specialized computer software to accomplish, In Germany public, using the ICEM. Flanging plastic part by bending the rebound fold angle changes, as illustrated in figure 4 B Click below. For this kind of problem, in addition to the Department of Drawing and cutting edge, but also including flanging and Wedge plastic, plastic take-off process is forming 2 -3, to offset the springback. The process design work completed and reflected in the number of program modules. 3 3 Wedge new outer body mold coverage on the application Currently, many of the new models outside panel, fender panels (Figure 5) front cover plate, the roof flanging plastic processes, used as a revolving Wedge, new technology. The working principle see figure 6, rotating Wedge part of the cavity is required plastic stamping parts of the region, when the plastic process is complete, Cylinder - driven carriers to promote Wedge around rotating drum rotation, so as to achieve the purpose of the yield components, After the convenience of plastic parts, removed from the mold. Rotating Wedges advantages are : plastic parts for stamping parts and materials entrusted part of the mosaic is very fairing, Therefore, there is no obvious parts indentation； Die simple structure； maintenance is simple and low cost. 4 Concluding remarks In recent years, through the tireless efforts and the car stamping die design and manufacturing capabilities made significant progress. However, the car is especially luxury cars outside the coverage of mold development, the international level and there are still more people gap. However, this gap is not narrowing, So long as we strengthen international exchanges and learn from their foreign counterparts in designing and manufacturing experience, car will be able to accelerate the coverage Die domestic process. References 1 C. Burke and R. Malloy, An experimental study of the ejection forces encountered during injection molding, SPE ANTEC Tech. Pap. 37 (1991). 2 R. Balsamo, D. Hayward and R. Malloy, An experimental evaluation of ejection forces: frictional effects, SPE ANTEC Tech. Pap. 39 (1993). 3 A.J. Pontes and A.S. Pouzada, Ejection force in tubular injection moldings. Part I: Effect of processing conditions, Polym. Eng. Sci. 44 (2004), p. 891. 4 G. Menges and H. Bangert, Measurement of coefficients of static friction as a means of determinating opening and demoulding forces in injection moulds, Kunstst. Ger. Plast. 71 (1981), p. 552. 5 B.J. Arajo and A.S. Pouzada, Design of ejection systems for injection moulds, O Molde 54 (2002), p. 36. 6 A.J. Pontes, A.M. Pinho, A.S. Miranda and A.S. Pouzada, Effect of processing conditions on ejection forces in injection moulds, O Molde 34 (1997), p. 25. 7 P. Collins, E.M.A. Harkin-Jones and P.J. Martin, The role of tool/sheet contact in plug-assisted thermoforming, Intern. Polym. Process. 17 (2002), p. 361. 8 P. Blau (Ed.), Friction, Lubrication and Wear Technology, ASM Handbook, vol. 18, ASM International, Ohio, 1992, p. 8. 9 N.A. Waterman and M.F. Ashby, The Materials Selector vol. 3, Chapman & Hall (1997). 10 D.I. James and W.G. Newell, A new concept in friction testing, Polym. Test. 1 (1980), p. 9. 11 M. Vaziri, F.H. Stott and R.T. Spurr, Studies of the friction of polymeric materials, Wear 122 (1988), p. 313. 12 R. Malloy and P. Majeski, Design of pin ejector systems for injection molds, SPE ANTEC Tech. Pap. 47 (1989). 13 P.A. Dearnley, Low friction surfaces for plastic injection moulding dies an experimental case study, Wear 229 (1999), p. 1109. 14 T. Sasaki, N. Koga, K. Shirai, Y. Kobayashi and A. Toyoshima, An experimental study on ejection force of injection molding, J. Precis. Eng. 24 (2000), p. 270. 15 A.J. Pontes, R. Pantani, G. Titomanlio and A.S. Pouzada, Ejection force in tubular injection moldings. Part II: A prediction model, Polym. Eng. Sci. 45 (2005), p. 325. 16 Friction and Wear Testing Source Book, ASM International, Ohio, 1997. 17 ISO 8295, Plastics Film and Sheeting Determination of the Coefficients of Friction, 1995. 国内外轿车覆盖件模具设计概况 A.S. Pouzada, E.C. Ferreira and A.J. Pontes 摘要 : 在介绍目前国内轿车冲压模具设计制造情况的基础上，阐述了国外汽车公司轿车覆盖件特别是外覆盖件的冲压工艺设计现状及模具新技术应用情况。 关键词 : 机械制造 ；轿车覆盖件 ；冲压工艺 ；模具设计 1 前言 近 几年来，我国轿车市场发展十分迅猛， 2002 年在轿车销售超过 100 万辆的基础上， 2003 年则向 200 万辆大关迈进，达到了 197 万辆。然而，在轿车热迅速升温的同时，不得不尴尬地面对这样的现实 市场上热销的绝 大 多数车型是直接从国外引进的。由于国内轿车覆盖件模具设计制造能力从总体上看还比较薄弱，为了生产这些车型，各 大 汽车公司不得不耗资几亿、十几亿元采购海外模具。与国外 大 汽车公司相比，由于生产规模比较小，这就造成单车均摊的模具成 本 远高于国外车，这也是造成国产车整车制造成木居高不下的主要原因之一。 2 国产轿车覆盖件模 具开发能力 国内主要的轿车模具制造商有 :一 汽模具制造有限公司、东风汽车模具厂、天津汽车模具有限公司、成飞集成科技股份有限公司、南京模具装备有限公司、上海千缘汽车车身模具有限公司等等。作为国内最 大 轿车生产销售商 上海 大 众汽车有限公司，也有自己的模具设计制造部门 (TMM 部 )。目前，虽然国内模具商在轿车内覆盖件模具设计制造方面已小有能力，并可承接整车厂的部分模具开发项目，但对于有很高型面精度和表面质量要求的外覆盖件，特别是中高档轿车的外覆盖件，整车厂很少会将这类模具交由国内开发。 上海 大 众汽车有限公司为了降低整 车生产成本，同时也为了提高公司的核心技术能力，从 2001年开始，涉足轿车冲压模具设计制造领域。 2001 年 -2002 年完成了 POLO 轿车在手动压机线上生产的10 只简单零件的模具，通过了公司质保部门验收并投产。 2002 年开始向大型化、复杂化、自动化发展，设计制造了 6000kN 自动线上生产的 POLO 轿车备胎座模具 (该零件外形尺寸大、拉深深度深、形状复杂 )2003 年，为进一步提高模具设计制造的能力和水平，我们涉足 20000kN 多工位压力机和10000kN 自动线生产使用的模具设计。过去上海大众在 20000kN 多工位 压力机上使用的模具，全部需进 u,国内模具商还没有能力设计制造这样的模具。为此，我们选择了 POLO 轿车中柱内板的模具进行设计。 20000kN 多工位压力机是世界上最先进的压力机之一，集成化、自动化程度非常高，当然这对模具设计的要求也相应地提高。零件的送料高度、步距、机械手的位置有严格的要求，还要保证机械手在运动过程中与模具无干涉，这样给予模具设计的空间就小了很多。在考虑诸多因素之后，我们最终完成了整套模具的设计，其 CAD 装配状态如图 1 所示。另外，我们还完成了 POLO 轿车在 10000kN自动线上生产的后轮罩的模具 设计，在去年的基础上更进一步。这些工作的顺利完成，标志着上海大众模具设计能力已经达到了国内先进水平，从而为今后上海大众汽车模具国产化打下了坚实的基础。尽管如此，与国际先进水平比较，仍有较大差距，比如在轿车外覆盖件模具设计方面还是空自。 在轿车冲模中，难度最 大 的是外覆盖件模具设计，主要表现在以下两个方面 : (1)克服由回弹造成的零件型面偏差 破裂、起皱、回弹是轿车冲压件成形过程中的主要缺陷，由于轿车外覆盖件外形尺寸大、拉深深度浅、塑性变形程度低，一般不易拉裂，因而回弹就成为该类 零件制造过程中的主要问题，它将严重影响零件间的相互配合关系。有限元模拟软件在冲压模具设计中得到普遍应用，已经能够比较准确地预测破裂和起皱，从而有助于设计合适的工艺补充面来改善拉深过程中材料的流动状况，提高零件的成形 ft。然而，迄今为 止 ，大多数有限元软件还不能精确地预测冲压件从模具当中取出后的回弹变形。因此，对外覆盖件回弹问题的处理，主要还是依靠经验来修改模具型面，使冲压件过正成形，来抵消由于回弹导致的变形。 (2)冲压件的取件 由于外覆盖件 (如前盖外板、车顶、翼子板 )都需进行复杂的翻边整形或预卷边工艺，这就 使得在模具结构设计时，必须考虑冲压件成形后的取件问题，目前，大都依靠复杂的多斜楔机构联动来实现模具工作部分对零件让位，以实现方便取件，由此造成整个模具的结构十分复杂。 3 国外覆盖件模具设计 目前，国外大汽车公司为了降低模具开发、制造成本，缩短生产周期，将除轿车外覆盖件之外的大部分轿车冲压件的模具都交由专业模具公司 (如 Fontana Pietro. Kuka. Laepple.Schuler Cartec.Ogi-hala-Fuji Techniaca 等等 )设计和制造，这些公司都有很强的开发能力，并在某些 零件的模具制造方面拥有独到的优势。但作为整车厂，考虑到新车型开发过程中的保密，对诸如翼子板、行李箱盖、车门、侧围、车顶、前盖等敏感零部件的模具，则都由自己的模具制造部门来设计和制造。 3.1 软件环境 冲压模具设计，除了必要的 CAD软件之外，还大量应用了有限元模拟软件，如 AutoForm.PamStamp. DynaForm. Indeed 等，来辅助冲压工艺设计。下面，以 AutoForm 为例，说明如何利用 CAE 软件来设计拉深工序工艺补充面。 AutoForm 是一款由瑞士开发的专业薄板成形快速模拟软件，可以用于 薄板、拼焊板的冲压成形、液压胀形等过程的模拟，配合不同的功能模块，还可以进行冲压件单步法成形模拟以及拉深工序工艺补充面 (Addendum)的设计。轿车冲压件中，约有 2/3 可以利用 AutoForm 的 Diedesigner Module 模块设计 Addendum，该模块根据由设计者指定的或由软件自动产生的压边圈型面，以及工艺补充面的多条截面线 (Profile)，能够快速地生成工艺补充面，用于拉深工序的模拟，如图 2 所示。压边圈型面、 Profile 均可进行参数化式的调整。这种快速设计是建立在对 Addendum 曲面的 粗略构造上的，即曲面面片本身以及曲面面片之间的连续并非十分光顺，尽管这种曲面不能够直接用于模具表面的机械加工，但是对于模拟精度的影响却不是很大。根据模拟结果，设计者可以很方便地对工艺补充面进行调整，直到模拟结果满足设计要求。最后，将压边圈、 Addendum 曲面和 Profile 以中性数据格式IGS 或 VDA 输出，在 CAD 软件中进行曲面重构，并结合产品数模，就能够得到机加工可以使用的拉深工序模具数模。 冲压工艺传统设计方法 :首先，在经验基础上，利用 CAD 设计工艺补充面 ；其 次，将 CAD 数模传递给 AutoForm 等 CAE 软件进行拉深过程模拟 ；根据模拟结果，在 CAD 中对工艺补充面进行调整，并将新的 CAD 数模传递给 CAE，开始新的模拟，直到满足要求为比。这是一个从 CAD 到 CAE 再回到 CAD 的不断反复的过程。由于每次在 CAD 中构造曲面都远较在 AutoForm 中复杂，因此，整个过程所花费的时间就多得多。而新方法在冲压工艺设计初期，就用 Diedesigner Module 在 AutoForm 软件中设计并调整拉深工艺补充面，与传统的设计方法相比，就能够大大提高设计效率。 由于 AutoForm 是一款快速模拟软件，为了在较短的时间内对复杂冲压件的成形过程进行评价，采用了膜单元来离散几何模型，必然要降低模拟精度，因此，有些汽车公司在模具设计开始之前还要利用模拟精度高的 CAE 软件，如德国大众就采用了 Indeed 软件，对拉深工序进行再次模拟 (Indeed软件的计算是基于带厚度的壳单元的，能够得到更为准确的计算结果，但是其计算所花费的时间通常是 AutoForm 的几到十几倍，该软件比较适用于最终验证 )，所有拉深工艺必须通过 Indeed 模拟并验证为是可行的，才可用于模具设计。 模具设计完备，应通过图纸结合 泡沫模型进行验收 (图 3)，各道工序用不同颜色的线条标记在泡沫模型上，这样做直观而清晰。还应组织包括工艺设计者、项目规划员、模具调试人员、模具操作者等相关人员进行讨论验收。对于在冲压工艺上难以解决的成形问题，还应邀请产品开发人员一同讨论，寻求对产品进行更改设计的可能性。 3.2 修正回弹的对策 由前已知，回弹是轿车外覆盖件成形过程中的主要问题，现以前盖外板为例，对此进行详细分析。 通常外覆盖件的回弹有以下两类 : 大片平坦曲面由弹性回复造成的拱起或塌陷，如图 4 中 C 部放大所示，虚线表示零件从模具中取出并 发生回弹后的位置。这类问题，工艺设计时通常不加以考虑，工艺数模中产品型面部分的数据与来自于产品开发部门的数据相一致，并用于模具制造。待试模之后，将试件与检具进行对比测量，根据偏差对拉深模型面进行修正。如果设计人员对于这类问题的控制拥有非常丰富经验的话，也可以事先估计出曲面弹性回复的方向以及偏移量，并将其反向叠加到产品数模上去，求得考虑回弹变形的拉深工艺曲面，这个计算过程需要由专门的计算机软件来完成，在德国大众，采用的是 ICEM。 翻边整形部分由弯曲变形回弹造成的折边转角变化，如图 4 中 B 部放大所示。对于这类 问题，该处除拉深和剪边外，还包括翻边和斜楔整形，整形工艺需过正成形 2 -3 ，以抵消弯曲回弹。该工作由工艺设计完成，并体现在工艺方案的数模中。 3.3 新斜楔机构在外覆盖件模具上的应用 目前，新车型的很多外覆盖件，如翼子板 (图 5)前盖外板、车顶等的翻边整形工序中，采用了一种称之为 “ 旋转斜楔 ” 的新工艺。其工作原理见图 6，旋转斜楔上的凹槽部分是冲压件需整形的区域，当整形过程完成后，气缸驱动的托架推动旋转斜楔绕滚筒转动，从而达到对零件让位的目的，方便整形后的零件从模具上取出。旋转斜楔的优点是 :因整形部分与冲压件托料部分的拼接处非常光顺，故零件上无明显压痕 ；模具结构简单 ；维修保养简便且费用低。 4 结束语 近年来，通过不懈的努力，国内轿车冲压模具的设计制造能力取得了显著的进步。但是，在轿车特别是中高档轿车外覆盖件模具的开发上，我们与国际水平仍有较大差距。不过，这种差距并非不能缩小，只要我们多加强国际交流，多吸取国