外文翻譯--成形模具設(shè)計(jì)中的板料成形數(shù)值模擬與試制模具的比較

1、<p><b>　　中文5520字</b></p><p>　　出處：Journal of Engineering Design, 2004, 15(6): 551-561</p><p><b>　　附錄</b></p><p><b>　　英文資料</b></p><

2、p>　　Comparison of sheet-metal-forming simulation and </p><p>　　try-out tools in the design of a forming tool</p><p>　　A. ANDERSSON</p><p>　　Today, sheet-metal-forming simulation

3、is a poAwerful technique for predicting the formability of automotive parts. Compared with traditional methods such as the use of try-out tools, sheet-metal-forming simulation enables a significant increase in the number

4、 of tool designs that can be tested before hard tools are manufactured. Another advantage of sheet-metal-forming simulation is the possibility to use it at an early stage of the design process, for example in the prelimi

5、nary design phase.Toda</p><p>　　1 Introduction</p><p>　　Traditionally, try-out tools are used to verify that a certain tool design will produce parts of the required quality. The try-out tools

6、are often made of a cheaper material (e.g. kirksite) than production tools in order to reduce the try-out costs. This is a very time-consuming and cost-consuming method. However, today another more efficient technique is

7、 available—sheet-metal-forming simulation. This new technique is based on the simulation of the forming process, and could result in a cost red</p><p>　　more and more accurate. In the future it will also be

8、possible to analyse more processes using sheet-metal-forming simulations. Today, the accuracy of the results in sheetmetal- forming simulation is high enough to replace the use of try-out tools to a great extent.</p&g

9、t;<p><b>　　2 Method</b></p><p>　　The purpose of this study is to analyse and compare the benefits and drawbacks of the use of sheet-metal-forming simulation and try-out tools in the desig

10、n of forming tools. The method employed in this study is based on the Production Reliability Matrix (PSM) (Rundqvist and Sta°hl 2001) together with a Process Correspondence Matrix (PCM) that has been developed espec

11、ially for this study. The PSM is a matrix that categorizes the effects of different factors (parameters) in the process into differ</p><p>　　3 Process for designing a forming tool</p><p>　　Figu

12、re 1 shows a simplified flow of the production process of developing a forming tool at Volvo Car Corporation, Body Components (VCBC).</p><p>　　The process of the design of a forming tool includes a try-out p

13、hase where different designs of the tool are tested. This is a very important stage in the tool design process,in order to verify that the part will fulfil the required quality. It is very difficult to predict the result

14、 of a forming operation, but by using sheet-metal-forming simulation there is a possibility to gain valuable insight into the outcome of the forming operation.</p><p>　　3.1 Use of sheet-metal-forming simula

15、tion</p><p>　　Sheet-metal-forming simulation can be used in several stages of a tool design process:</p><p>　　●early in the preliminary design phase, to enable rapid verification of different pr

16、oposals for the design of automotive components</p><p>　　●to improve an existing process.</p><p>　　3.1.1. Requirements for sheet-metal-forming simulation.</p><p>　　Sheet-metal-formi

17、ng simulation requires the following:</p><p>　　●Simulation software.</p><p>　　●A computer-aided design (CAD) model of the part layout or a CAD model of the forming surfaces of the tool.</p>

18、;<p>　　●Parameters for description of the specified sheet-metal material.</p><p>　　●Process parameters.</p><p>　　●Workstations (today the development of the personal computer (PC) is rapi

19、dly advancing so that PCs will be a strong alternative in the future).</p><p>　　●A competent staff that can handle the software and analyse the results of the simulation.</p><p>　　Simulation sof

20、tware. Today there is a variety of commercial software available on the market. In order to find suitable software, the area of use must be analysed. The software package is different with regard to user-friendliness and

21、 flexibility.</p><p>　　At VCBC, where this study was performed, two different software packages are used. One is Autoform (2001), which is user-friendly and provides fast results. This software is used for t

22、he iterative process of finding the proper tool geometry. The other software is LS-DYNA (2001), which is used at VCBC to verify the results of</p><p><b>　　Autoform.</b></p><p>　　CAD

23、model. In order to analyse a part or a tool design using sheet-metal-forming simulation, a CAD model of the part or tool is needed. This model can be created in most CAD programs, for instance CATIA, which is used at VCB

24、C. Different simulation software demand different qualities of the CAD models.</p><p>　　Material parameters. Uniaxial tensile tests are used to describe the material parameters. There is also a need for desc

25、ribing the risk of fracture in the material. Data regarding risk for fracture are obtained by creating a forming limit curve. The forming limit curve is a curve in the plane of principal strains that indicates the maximu

26、m allowed strain values before fracture occurs. A more thorough description is presented in Pearce (1991).</p><p>　　Process parameters. Sheet-metal-forming simulation requires proper process parameters (e.g.

27、 drawbeads).</p><p>　　Workstations. The simulation models that are used in sheet-metal-forming simulation are generally so large that they require a workstation in order to achieve reasonable calculation tim

28、es. However, the development of PCs enables the clustering of several PCs, which can be an alternative to workstations.</p><p>　　Competent personnel. In order to interpret the results of a sheet-metal-formin

29、g simulation, it is necessary to enter the correct input data and possess the ability to understand the results. This requires competent personnel. The competence should consist of both forming knowledge and simulation k

30、nowledge since that gives a natural connection between the production process and the interpretation of the results.</p><p>　　Table 1 Material data for V-1158.</p><p>　　3.2. Results of a sheet-

31、metal-forming simulation</p><p>　　Sheet-metal-forming simulation enables the study of:</p><p>　　●Thickness distribution.</p><p>　　●Risk of fracture.</p><p>　　●Draw line

32、s.</p><p>　　●Wrinkles.</p><p>　　●Drawbeads/ blankholder pressure.</p><p>　　●Surface defects.</p><p>　　●Stability of the surface.</p><p>　　●Springback.</

33、p><p>　　●Material behaviour.</p><p>　　●Process surveillance.</p><p><b>　　●Draw in.</b></p><p>　　●Forming window.</p><p>　　●Forces (punch, blankhol

34、der).</p><p>　　In order to demonstrate possible results, a simulation of a Body Side Outer from a Volvo S80 has been studied. The material used for this automotive component is a mild steel with good formabi

35、lity (V-1158). Material data are presented in table 1.</p><p>　　3.2.1. Thickness distribution. </p><p>　　The sheet-metal-forming simulation can provide a good approximation of the thickness dist

36、ribution for a part (see figure 2). In the automotive industry there are requirements concerning the maximum allowable reduction in thickness, in order to ensure safety margins in the event of a crash.</p><p&g

37、t;　　3.2.2. Risk for fracture. Risk for fracture during the forming process could be evaluated by means of a forming limit curve, which was described earlier in this section.</p><p>　　3.2.3. Draw lines. Draw

38、lines occur when a visible section of an exterior part has been gliding over a radius during forming. A plot of how a point on the part surface moves during the simulation (see figure 4) illustrates these lines. Draw lin

39、es are not acceptable on a visible surface on an exterior part.</p><p>　　In figure 5, which describes formability, surfaces with enough strains to be stable can be seen. By studying these images together it

40、is possible to estimate the stability of the surfaces. This is a simplified analysis. A more detailed analysis would include the interaction between stresses and strains for the complete part.</p><p>　　3.2.4

41、 Wrinkles. Visible wrinkles are not allowed on a part. These can be detected with sheet-metal-forming simulation (see figure 6).</p><p>　　3.2.5 Forces. In order to dimension the process in an accurate way,

42、 it is necessary to know which forces are necessary to form the part. The data for these forces can be obtained from the results of a sheet-metal-forming simulation.</p><p>　　3.2.6 Surface defects. Exterior

43、 automotive parts are sensitive to deflections of the surface that can occur during forming. These deflections can be very small but can still be visible after the part is painted, which means that the part must be scrap

44、ped.The defects can be detected by the human hand as it moves gently across the surface.Sheet-metal-forming simulation can be used for detecting risk areas through analysis of the stress strain distribution.。</p>

45、<p>　　3.2.7 Stability of the surface. Stable surfaces are required in order to increase the stiffness of the part to prevent the part from becoming unstable and vibrating. Sheet-metal-forming simulation can be used

46、 for detecting risk areas through analysis of the strain distribution. Figure 6 describes a simplified analysis. A more detailed analysis would include the interaction between stresses and strains for the complete part.。

47、</p><p>　　3.2.8 Springback. Springback is a phenomenon that could be described as a change in geometry that occurs after the parts have been removed from the forming tool. This g eometry change causes misma

48、tch for the part when it is assembled with other parts.</p><p>　　3.2.9 Process surveillance. In sheet-metal-forming simulation, the process can be followed in detail by means of animations. Figure 5 illustr

49、ates this.</p><p>　　3.2.10 Draw in. To minimize material consumption, it is important to optimize the shape of the blank. Sheet-metal-forming simulation can facilitate optimization of the blank by analysing

50、 the draw in (see figure 7).</p><p>　　3.2.11 Forming window. A forming window could be described as the allowable variation of the process parameters in order to keep the quality of the produced parts.</

51、p><p>　　3.3. Use of try-out tools</p><p>　　Try-out tools are used when the design of the process is to be verified (see figure 1).Based on this design the try-out tools are then cast in kirksite, f

52、or example. Prototype parts are then produced from this try-out tool. There are several differences between a try-out tool and a production tool. One is that the try-out tool wears out much faster than a production tool.

53、 Therefore, it is not possible to produce so many parts in a try-out tool. Another difference is that a try-out tool is much c</p><p>　　The PSM can be used to determine which parameters have significant effe

54、cts on the stability of the process. It is also possible to determine the extent of an effect. This provides valuable help in the identification of the most severe problems. These severe problems are especially interesti

55、ng since they are the most cost-effective when solved. A more detailed description of the PSM is presented by Rundqvist and Sta°hl (2001). An example where the PSM is applied is presented in Pettersson (1991),</p

56、><p><b>　　5 Result</b></p><p>　　The technique of using try-out tools has been compared with the technique of using sheet-metal-forming simulation from two aspects. The first aspect is

57、a comparison of the ability to predict the different parameters of the production process, mentioned in section 3. The second aspect is the ability to verify which process parameters should be studied.</p><p&g

58、t;　　5.1 Study of agreement of predicted process with production process</p><p>　　The PCM allows a clear comparison between try-out tools and simulation regarding correspondence with the production process.

59、Table 2 presents the different fields of applications for the different techniques together with the ability to predict behaviour in the production process. The values in table 2 have been determined through extensive in

60、terviews with senior forming experts.</p><p>　　In table 2 the following scale is used:</p><p>　　5 The results show perfect agreement with the production process.</p><p>　　4 The resu

61、lts show good agreement with the production process. Special cases can deviate.</p><p>　　3 The results show good agreement in most cases with the production process.</p><p>　　2 The results show

62、good agreement in certain cases with the production process. Indirect interpretation of the results is needed.</p><p>　　1 The results show no agreement with the production process. It cannot be used for proc

63、ess prediction or verification.</p><p>　　Comments on table 2 include the following:</p><p>　　● The difference between risk for fracture and actual fracture is that risk for fracture shows areas

64、that have not cracked but where necking has appeared.</p><p>　　●The parameter ‘Material characteristics’ refers to the ability to predict the quality of the part depending on variation in the material qualit

65、y.</p><p>　　● Process surveillance enables the monitoring of how different parameters change during the process.</p><p>　　●The forming window is an aid for detecting how sensitive the process is

66、 to disturbances.</p><p>　　●The values for the tool forces are based on the assumption that it is possible to measure the forces in the try-out press.</p><p>　　Table 2. Process Correspondence Ma

67、trix (PCM): correspondence with the production process.</p><p>　　5.2 Study of which factors in the production process are possible to analyse</p><p>　　The concept of grouping different factors

68、that are typical for the production process into different factor groups has been used in this study according to the PSM model. In a previous study (Andersson et al. 1999), different factors concerning the forming of al

69、uminium were studied. This work has been modified in order to facilitate a comparison between the two techniques for prediction and verification considered in this study; namely, sheet-metal-forming simulation and try-ou

70、t tools. See table</p><p>　　In table 3 the following scale is used:</p><p>　　3 The results show perfect prediction of production process.</p><p>　　2 The results show direct predicti

71、on of production process.</p><p>　　1 The results show indirect prediction of production process.</p><p>　　0 The results cannot predict production process at all.</p><p>　　5.3. Restr

72、iction /expansion of test possibilities</p><p>　　An analysis of tables 2 and 3 shows several advantages of using sheet-metal-simulation in the tool design process. However, one of the biggest advantages of s

73、heetmetal- forming simulation is that it enables the testing of many different designs of the part, tool or process, which generates substantial savings in costs and time. In this respect, try-out tools are more limited

74、and expensive, which means that only a minimum number of try-out tools are produced. The use of try-out tools contributes </p><p>　　6. Conclusions</p><p>　　The use of sheet-metal-forming simula

75、tion leads to a significant reduction in both cost and time compared with the use of try-out tools. The requirement is that the respective parameter for study (see section 3.1.2) demonstrates good correspondence between

76、simulation and actual production processes. Sheet-metal-forming simulation is also superior to try-out tools with regard to predicting and verifying the forming process. </p><p>　　The investment requirements

77、 are relatively small when starting to implement sheet-metal-forming simulation. It is necessary to invest in a workstation and software, which cost about SEK 500,000. In addition, it is necessary to have competent perso

78、nal for handling the sheet-metal-forming simulation. Compared with the investment for one try-out tool (.SEK 500,000 per tool), it is clear that there is a lot to gain in reducing cost and time if sheet-metal-forming sim

79、ulation is used when it is suitab</p><p>　　Table 3. The possibilities to predict different factors (parameters) in the production process </p><p>　　compared in a Production Reliability Matrix (P

80、SM)</p><p>　　Assuming the possibility of measuring forces in the try-out tool.</p><p>　　As stated earlier, today the accuracy of the results in sheet-metal-forming simulation is high enough to r

81、eplace the use of try-out tools to a great extent. The use of try-out tools in the tool design process may be necessary for some time to come to verify some process parameters, but the following advantages are closely as

82、sociated with sheet-metal-forming simulation:</p><p>　　● Deeper insight into the process at significantly earlier stages.</p><p>　　● Greater flexibility in testing designs for the part, the tool

83、 and the process.</p><p>　　● Greater understanding of when try-out tools should be used, making try-out tools much more cost-effective.</p><p>　　● Greater potential to design cars with more dari

84、ng designs.</p><p>　　● Greater possibility to test new materials for the automotive parts.</p><p>　　● Greater competitive advantage due to more daring designs, lower costs and shorter lead times

85、.</p><p>　　7 Comments</p><p>　　At VCBC, where this study was carried out, sheet-metal-forming simulation is today a natural part of the tool design process. Sheet-metal-forming simulation has b

86、een used in manufacturing since 1995 and the experiences have been very good. Today all processes that are so complex that it is difficult to choose process conditions based on experience are simulated. During the develo

87、pment of the Volvo S80, which was the first car project to use simulation technology in full scale, it was established</p><p>　　Acknowledgement</p><p>　　The author would like to express gratitud

88、e to colleagues at VCBC, who have contributed much valuable information and interesting discussions during this work. He would also like to thank his supervisor, Professor Jan-Eric Sta°hl (Division of Production and

89、 Materials Engineering, Lund University), and his co-supervisor, Professor Kjell Mattiasson (Chalmers University of Technology), for their support and constructive criticism of the article.</p><p>　　Referenc

90、es</p><p>　　ANDERSSON, A., ASSARSSON, J. and INGEMANSSON, A., 1999, Front fender—aluminium versus steel, a study in PROPER’s research areas at VOLVO. Working Paper LUTMDN/(TMMV-7023)/1-18/2001, Lund Universi

91、ty, Lund, Sweden.;</p><p>　　AUTOFORM, 2001, http://www.autoform.de, April.;</p><p>　　LS-DYNA, 2001, http://www.lstc.com, April.;</p><p>　　PEARCE, R., 1991, Sheet Metal Forming, edit

92、ed by J. Wood (Bristol: Adam Hilger), pp. 143–169.</p><p>　　PETTERSSON, M., 1991, Produktionssto¨rningar i presslinjer. Division of Production and Materials Engineering, Lund University, Lund, Sweden.;&

93、lt;/p><p>　　RUNDQVIST, T. and STA° HL, J.-E., 2001, Tillverkningssystem, Division of Production and Materials Engineering, Lund..</p><p><b>　　中文翻譯</b></p><p>　　成形模具設(shè)計(jì)中

94、的板料成形數(shù)值模擬與試制模具的比較</p><p>　　當(dāng)今，金屬板料成形數(shù)值模擬是一種用于預(yù)測(cè)汽車零部件成形能力的強(qiáng)有力的技巧。與傳統(tǒng)的方法比如使用試制模具，金屬板料成形數(shù)值模擬在模具設(shè)計(jì)中應(yīng)用程度的巨大的增加使實(shí)體模具在制造之前被測(cè)試成為可能。另外一種金屬板料成形模擬的優(yōu)點(diǎn)在于其可利用于工藝設(shè)計(jì)早期階段，例如在最初的設(shè)計(jì)階段。如今，金屬板料成形數(shù)值模擬的結(jié)果的精確度在很大程度上已足夠高，以致于可代替試制模具的

95、使用。在沃爾沃汽車公司，車身部件工廠，該項(xiàng)研究已經(jīng)被啟動(dòng)，金屬板料成形模擬以集成的模塊形式在模具設(shè)計(jì)與模具生產(chǎn)的工藝中被使用。</p><p><b>　　引言</b></p><p>　　傳統(tǒng)地，試制模具被用于驗(yàn)證某種模具設(shè)計(jì)能否生產(chǎn)滿足要求質(zhì)量的零件。試制模具通常由比生產(chǎn)用模具更便宜的材料制成。這是一種很省時(shí)且節(jié)約成本的方式。但是，如今另外一種更為行之有效的技術(shù)可

96、以使用——金屬板料成形模擬。這種新技術(shù)基于成形工藝的數(shù)值模擬，并且對(duì)于每套實(shí)用模具可以降低10%的成本和15%的生產(chǎn)時(shí)間。金屬板料成形數(shù)值模擬技術(shù)不斷的發(fā)展，并且模擬的結(jié)果越來越精確。在將來，或許可以使用金屬板料成形數(shù)值模擬用于分析更多的工藝。如今，金屬板料成形數(shù)值模擬的結(jié)果的精確度在很大程度上已足夠高可代替試制模具的使用。</p><p><b>　　方法</b></p>&

97、lt;p>　　該研究的目的在于分析和比較金屬板料成形數(shù)值模擬和試制模具在成形模具設(shè)計(jì)中的優(yōu)缺點(diǎn)。此研究中使用的方法基于專為該研究開發(fā)的產(chǎn)品可靠性模板（PSM) (Rundqvist and Sta°hl 2001年)和工藝一致性模板 (PCM)。PSM是一種把工藝中的不同因素（參數(shù)）按目錄編入不同因素組的模板。然后每種因素（參數(shù)）的影響被評(píng)定為0—3等級(jí)?；谀０宓慕Y(jié)果，對(duì)產(chǎn)品工藝有最大影響的參數(shù)可以被篩選出來，然后可以

98、制作折中或是最小化這些影響的優(yōu)先表。PCM是通過高級(jí)專家測(cè)試在實(shí)際生產(chǎn)中對(duì)汽車元器件成形的連續(xù)測(cè)試來分析金屬板料成形數(shù)值模擬、試制模具的結(jié)果，生產(chǎn)零件的質(zhì)量</p><p><b>　　設(shè)計(jì)成形模具的工藝</b></p><p>　　圖1所示，一種在沃爾沃汽車公司車身部件工廠（VCBC）的開發(fā)一種成形模具的簡(jiǎn)化生產(chǎn)工藝流程。</p><p>　

99、　一種成形模具設(shè)計(jì)的工藝包括試制階段，該階段各種不同的模具設(shè)計(jì)被測(cè)試。這是一個(gè)在模具設(shè)計(jì)工藝中很重要的階段，目的在于驗(yàn)證零件將會(huì)滿足所要求的質(zhì)量。預(yù)測(cè)一種成形操作的結(jié)果是很困難的，但是通過使用金屬板料成形數(shù)值模擬方法使得對(duì)成形操作的結(jié)果有價(jià)值的預(yù)測(cè)成為可能。</p><p>　　3.1 金屬板料成形數(shù)值模擬的使用</p><p>　　金屬板料成形數(shù)值模擬可以被利用到模具設(shè)計(jì)工藝的幾個(gè)階段

100、。</p><p>　　起初設(shè)計(jì)的早期階段，能夠快速驗(yàn)證汽車元器件設(shè)計(jì)的不同的方案</p><p>　　預(yù)測(cè)并且驗(yàn)證成形工藝</p><p><b>　　改善現(xiàn)有的工藝</b></p><p>　　3.1.1 金屬板料成形數(shù)值模擬的需求</p><p><b>　　● 數(shù)值模擬軟件&

101、lt;/b></p><p>　　● 零件布局的CAD模型或模具成形表面的CAD模型</p><p>　　● 描述特定金屬板料材料的參數(shù)</p><p><b>　　● 工藝參數(shù)</b></p><p>　　● 工作站（現(xiàn)今個(gè)人計(jì)算機(jī)的發(fā)展快速的提升以致于個(gè)人計(jì)算機(jī)在將來會(huì)成為一種強(qiáng)有力的替代）</p

102、><p>　　● 一名有能力可以操作該軟件并能夠分析數(shù)值模擬結(jié)果的員工</p><p>　　數(shù)值模擬軟件?，F(xiàn)今市場(chǎng)有各種各樣的商業(yè)軟件可供使用。為找到合適的軟件，必須分析所使用的領(lǐng)域?？紤]到用戶界面友好性與軟件柔性，軟件包是不同的。</p><p>　　在進(jìn)行該項(xiàng)研究的VCBC，兩種不同的軟件包得以使用。一種是用戶友好的可快速提供結(jié)果的AUTOFORM（2001）。該