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濟(jì)源職業(yè)技術(shù)學(xué)院畢業(yè)設(shè)計(jì) I 摘要 目前機(jī)械廠普遍采用線切割加工制造電器產(chǎn)品專用墊片的工藝，該生產(chǎn)工藝效率低， 成本高；本文提出采用模具來(lái)生產(chǎn)墊片的新工藝，并針對(duì)某機(jī)械廠一規(guī)格墊片設(shè)計(jì)了級(jí) 進(jìn)模，該模具沖裁的設(shè)計(jì)難點(diǎn)主要是如何解決好零件中的小孔沖裁、確定模具結(jié)構(gòu)、如 何進(jìn)行模具的制造及沖裁方案選定等。 本文結(jié)合墊片的特點(diǎn)，通過(guò)采取給小凸模加保護(hù)套，在模具結(jié)構(gòu)上選用倒裝復(fù)合模 取代以往采用的正裝復(fù)合模，這樣廢料不落在模具表面便于工人操作；在模具制造過(guò)程 中，為了提高凸模的韌性防止在使用過(guò)程中折斷，采用 模具鋼取代常規(guī)采用的12rnCMV 模具鋼，并采用真空熱處理，硬度取 ；在裝配過(guò)程中為了提高凸模的穩(wěn)12rC579HR 定性，凸模與凸模固定板的裝配采用厭氧膠固定等措施，較好的解決了沖裁方案的確定、 模具結(jié)構(gòu)選擇、壓力機(jī)頭的選擇與校核、凸、凹模刃口尺寸計(jì)算及結(jié)構(gòu)設(shè)計(jì)、定位方案 設(shè)計(jì)、卸料方式的設(shè)計(jì)、模架的確定及模具設(shè)計(jì)制造困難等問(wèn)題。 目前該模具已經(jīng)制造試沖完畢，交付工廠使用且已經(jīng)制造出上萬(wàn)個(gè)墊片，零件尺寸 精度比較高，效果良好，生產(chǎn)效率提高 10 倍以上，成本降低 5 倍以上，完全符合要求。 關(guān)鍵詞：沖孔，落料，級(jí)進(jìn)模 濟(jì)源職業(yè)技術(shù)學(xué)院畢業(yè)設(shè)計(jì) II 前言 模具，是工業(yè)生產(chǎn)的基礎(chǔ)工藝裝備，在電子、汽車、電機(jī)、電器、儀表、家電和通 訊等產(chǎn)品中，6080的零部件都依靠模具成形，模具質(zhì)量的高低決定著產(chǎn)品質(zhì)量的 高低，因此，模具被稱之為“百業(yè)之母”。模具又是“效益放大器”，用模具生產(chǎn)的最 終產(chǎn)品的價(jià)值，往往是模具自身價(jià)值的幾十倍、上百倍。 模具生產(chǎn)的工藝水平及科技含量的高低，已成為衡量一個(gè)國(guó)家科技與產(chǎn)品制造水平 的重要標(biāo)志，它在很大程度上決定著產(chǎn)品的質(zhì)量、效益、新產(chǎn)品的開(kāi)發(fā)能力，決定著一 個(gè)國(guó)家制造業(yè)的國(guó)際競(jìng)爭(zhēng)力。 我國(guó)模具工業(yè)的技術(shù)水平近年來(lái)也取得了長(zhǎng)足的進(jìn)步。大型、精密、復(fù)雜、高效和 長(zhǎng)壽命模具上了一個(gè)新臺(tái)階。大型復(fù)雜沖模以汽車覆蓋件模具為代表，已能生產(chǎn)部分新 型轎車的覆蓋件模具。體現(xiàn)高水平制造技術(shù)的多工位級(jí)進(jìn)模的覆蓋面，已從電機(jī)、電器 鐵芯片模具，擴(kuò)展到接插件、電子槍零件、空調(diào)器散熱片等家電零件模具。在精密塑料 模具方面，已能生產(chǎn)照相機(jī)塑料模具、多型腔小模數(shù)齒輪模具及塑封模具等。在大型精 密復(fù)雜壓鑄模方面，國(guó)內(nèi)已能生產(chǎn)自動(dòng)扶梯整體踏板壓鑄模和及汽車后橋齒輪箱壓鑄模 及其他類型的模具，例如子午線輪胎活絡(luò)模具、鋁合金和塑料門(mén)窗異型材擠出模等，也 都達(dá)到了較高的水平，并可替代進(jìn)口模具。 雖然如此，我國(guó)的沖壓模具設(shè)計(jì)制造能力與市場(chǎng)需要和國(guó)際先進(jìn)水平相比仍有較大 差距，這些主要表現(xiàn)在高檔轎車和大中型汽車覆蓋件模具及高精度沖模方面，無(wú)論在設(shè) 計(jì)還是加工工藝和能力方面，都有較大差距。轎車覆蓋件模具，具有設(shè)計(jì)和制造難度大， 質(zhì)量和精度要求高的特點(diǎn)，可代表覆蓋件模具的水平。雖然在設(shè)計(jì)制造方法和手段方面 已基本達(dá)到了國(guó)際水平，模具結(jié)構(gòu)功能方面也接近國(guó)際水平，在轎車模具國(guó)產(chǎn)化進(jìn)程中 前進(jìn)了一大步，但在制造質(zhì)量、精度、制造周期等方面，與國(guó)外相比還存在一定的差距。 標(biāo)志沖模技術(shù)先進(jìn)水平的多工位級(jí)進(jìn)模和多功能模具，是我國(guó)重點(diǎn)發(fā)展的精密模具品種。 有代表性的是集機(jī)電一體化的鐵芯精密自動(dòng)閥片多功能模具，已基本達(dá)到國(guó)際水平，但 總體上和國(guó)外多工位級(jí)進(jìn)模相比，在制造精度、使用壽命、模具結(jié)構(gòu)和功能上，仍存在 一定差距，這說(shuō)明我們還有相當(dāng)長(zhǎng)的一段路要走，同時(shí)也要求我們模具設(shè)計(jì)人員在工作 中要刻苦努力，不斷創(chuàng)新，打造屬于自己的品牌，所以需要我們更努力的去奮斗！ 濟(jì)源職業(yè)技術(shù)學(xué)院畢業(yè)設(shè)計(jì) 3 目錄 摘 要 .II 前 言 .III 1 墊片圖紙及設(shè)計(jì)要求 .1 1.1 零件圖 .1 1.2 設(shè)計(jì)要求 .1 2 沖壓工藝及模具設(shè)計(jì) .2 2.1 零件沖裁工藝性分析 .2 2.2 確定沖壓工藝方案 .2 2.3 模具結(jié)構(gòu)的確定 .3 2.4 排樣方案的確定及計(jì)算 .3 2.5 沖裁間隙的確定 .6 2.6 沖裁力和壓力中心的計(jì)算 .6 2.7 工作零件刃口尺寸計(jì)算 .8 2.8 工作零件結(jié)構(gòu)尺寸 .10 2.9 小孔沖裁小凸模的設(shè)計(jì) .11 3 模具材料的選用及其他零部件的設(shè)計(jì) .13 3.1 級(jí)進(jìn)模的特點(diǎn) .13 3.2 模具材料的選用 .13 3.3 定位零件的選擇 .15 3.4 卸料、出件、導(dǎo)向方式的選擇 .16 3.5 模架的確定 .17 3.6 連接與固定零件 .17 3.7 其它模具零件結(jié)構(gòu)尺寸列表 .19 3.8 沖壓機(jī)的選擇 .19 4 模具總裝配圖及零件加工工藝 .21 4.1 模具總裝配 .21 4.2 模具零件加工工藝 .23 5 模具的裝配和沖裁模具的試沖 .25 5.1 模具的裝配 .25 5.2 沖裁模具的試沖 .26 致 謝 .29 參考文獻(xiàn) .30 濟(jì)源職業(yè)技術(shù)學(xué)院畢業(yè)設(shè)計(jì) 4 濟(jì)源職業(yè)技術(shù)學(xué)院
機(jī)電系2008屆畢業(yè)生畢業(yè)設(shè)計(jì)答辯記錄
姓 名
郭大慶
專 業(yè)
模具設(shè)計(jì)與制造
班 級(jí)
0501
答辯時(shí)間
答辯地點(diǎn)
設(shè)計(jì)題目
墊片導(dǎo)正銷定距級(jí)進(jìn)模設(shè)計(jì)
1.設(shè)計(jì)排樣時(shí)應(yīng)考慮哪些因素？
答：（1）提高材料的利用率；
（2）模具結(jié)構(gòu)簡(jiǎn)單，能提高模具壽命；
（3）排樣方法應(yīng)使沖壓操作方便，減小勞動(dòng)強(qiáng)度且保證安全；
（4）保證制件質(zhì)量和制件板料對(duì)纖維方向的要求。
2.沖裁間隙的調(diào)整有哪幾種方法？
答：（1）透光法 （2）測(cè)量法 （3）墊片法
（4）涂層法 （5）鍍銅法
3.確定搭邊值的因素有哪些？
答：1）.沖件的尺寸和形狀；
2）.材料的硬度和厚度；
3）.排樣的形式（直排、斜排、對(duì)排）；
4）.條料的送進(jìn)方式（是否有側(cè)壓板）；
5）.擋料裝置的形式（擋料銷、導(dǎo)料銷、定距側(cè)刃）；
4.卸料裝置的形式和作用？
答：卸料裝置的形式包括固定卸料板、活動(dòng)卸料板、彈壓卸料板和廢料切刀等,卸料板除了把料從凸模上卸下外，有時(shí)也起壓料或?yàn)橥鼓?dǎo)向的作用。
5.落料和沖孔的區(qū)別？
答：落料件的尺寸取決于凹模，因此落料模應(yīng)先決定凹模尺寸，用減小凸模尺寸來(lái)保證合理間隙；沖孔件的尺寸取決于凸模，因此沖孔模應(yīng)先決定凸模尺寸，用增大凹模尺寸來(lái)保證合理間隙。
記錄教師（簽名）：
第 26 頁(yè) 共 27 頁(yè)
e pos 模具工業(yè)現(xiàn)狀Process simulation in stamping – recent
applications for product and process design
Abstract
Process simulation for product and process design is currently being practiced in industry. However, a number of input variables have a significant effect on the accuracy and reliability of computer predictions. A study was conducted to evaluate the capability of FE-simulations for predicting part characteristics and process conditions in forming complex-shaped, industrial parts.
In industrial applications, there are two objectives for conducting FE-simulations of the stamping process; (1) to optimize the product design by analyzing formability at the product design stage and (2) to reduce the tryout time and cost in process design by predicting the deformation process in advance during the die design stage. For each of these objectives, two kinds of FE-simulations are applied. Pam-Stamp, an incremental dynamic-explicit FEM code released by Engineering Systems Int'l, matches the second objective well because it can deal with most of the practical stamping parameters. FAST_FORM3D, a one-step FEM code released by Forming Technologies, matches the first objective because it only requires the part geometry and not the complex process information.
In a previous study, these two FE codes were applied to complex-shaped parts used in manufacturing automobiles and construction machinery. Their capabilities in predicting formability issues in stamping were evaluated. This paper reviews the results of this study and summarizes the recommended procedures for obtaining accurate and reliable results from FE simulations.
In another study, the effect of controlling the blank holder force (BHF) during the deep drawing of hemispherical, dome-bottomed cups was investigated. The standard automotive aluminum-killed, drawing-quality (AKDQ) steel was used as well as high performance materials such as high strength steel, bake hard steel, and aluminum 6111. It was determined that varying the BHF as a function of stroke improved the strain distributions in the domed cups.
Keywords: Stamping; Process ;stimulation; Process design
1. Introduction
The design process of complex shaped sheet metal stampings such as automotive panels, consists of many stages of decision making and is a very expensive and time consuming process. Currently in industry, many engineering decisions are made based on the knowledge of experienced personnel and these decisions are typically validated during the soft tooling and prototyping stage and during hard die tryouts. Very often the soft and hard tools must be reworked or even redesigned and remanufactured to provide parts with acceptable levels of quality.
The best case scenario would consist of the process outlined in Fig. 1. In this design process, the experienced product designer would have immediate feedback using a specially design software called one-step FEM to estimate the formability of their design. This would allow the product designer to make necessary changes up front as opposed to down the line after expensive tooling has been manufactured. One-step FEM is particularly suited for product analysis since it does not require binder, addendum, or even most process conditions. Typically this information is not available during the product design phase. One-step FEM is also easy to use and computationally fast, which allows the designer to play “what if” without much time investment.
Fig. 1. Proposed design process for sheet metal stampings.
Once the product has been designed and validated, the development project would enter the “time zero” phase and be passed onto the die designer. The die designer would validate his/her design with an incremental FEM code and make necessary design changes and perhaps even optimize the process parameters to ensure not just minimum acceptability of part quality, but maximum achievable quality. This increases product quality but also increase process robustness. Incremental FEM is particularly suited for die design analysis since it does require binder, addendum, and process conditions which are either known during die design or desired to be known.
The validated die design would then be manufactured directly into the hard production tooling and be validated with physical tryouts during which the prototype parts would be made. Tryout time should be decreased due to the earlier numerical validations. Redesign and remanufacturing of the tooling due to unforeseen forming problems should be a thing of the past. The decrease in tryout time and elimination of redesign/remanufacturing should more than make up for the time used to numerically validate the part, die, and process.
Optimization of the stamping process is also of great importance to producers of sheet stampings. By modestly increasing one's investment in presses, equipment, and tooling used in sheet forming, one may increase one's control over the stamping process tremendously. It has been well documented that blank holder force is one of the most sensitive process parameters in sheet forming and therefore can be used to precisely control the deformation process.
By controlling the blank holder force as a function of press stroke AND position around the binder periphery, one can improve the strain distribution of the panel providing increased panel strength and stiffness, reduced springback and residual stresses, increased product quality and process robustness. An inexpensive, but industrial quality system is currently being developed at the ERC/NSM using a combination of hydraulics and nitrogen and is shown in Fig. 2. Using BHF control can also allow engineers to design more aggressive panels to take advantage the increased formability window provided by BHF control.
Fig. 2. Blank holder force control system and tooling being developed at the ERC/NSM labs.
Three separate studies were undertaken to study the various stages of the design process. The next section describes a study of the product design phase in which the one-step FEM code FAST_FORM3D (Forming Technologies) was validated with a laboratory and industrial part and used to predict optimal blank shapes. Section 4 summarizes a study of the die design stage in which an actual industrial panel was used to validate the incremental FEM code Pam-Stamp (Engineering Systems Int'l). Section 5 covers a laboratory study of the effect of blank holder force control on the strain distributions in deep drawn, hemispherical, dome-bottomed cups.
2. Product simulation – applications
The objective of this investigation was to validate FAST_FORM3D, to determine FAST_FORM3D's blank shape prediction capability, and to determine how one-step FEM can be implemented into the product design process. Forming Technologies has provided their one-step FEM code FAST_FORM3D and training to the ERC/NSM for the purpose of benchmarking and research. FAST_FORM3D does not simulate the deformation history. Instead it projects the final part geometry onto a flat plane or developable surface and repositions the nodes and elements until a minimum energy state is reached. This process is computationally faster than incremental simulations like Pam-Stamp, but also makes more assumptions. FAST_FORM3D can evaluate formability and estimate optimal blank geometries and is a strong tool for product designers due to its speed and ease of use particularly during the stage when the die geometry is not available.
In order to validate FAST_FORM3D, we compared its blank shape prediction with analytical blank shape prediction methods. The part geometry used was a 5?in. deep 12?in. by 15?in. rectangular pan with a 1?in. flange as shown in Fig. 3. Table 1 lists the process conditions used. Romanovski's empirical blank shape method and the slip line field method was used to predict blank shapes for this part which are shown in Fig. 4.
Fig. 3. Rectangular pan geometry used for FAST_FORM3D validation.
Table 1. Process parameters used for FAST_FORM3D rectangular pan validation
Fig. 4. Blank shape design for rectangular pans using hand calculations.
(a) Romanovski's empirical method; (b) slip line field analytical method.
Fig. 5(a) shows the predicted blank geometries from the Romanovski method, slip line field method, and FAST_FORM3D. The blank shapes agree in the corner area, but differ greatly in the side regions. Fig. 5(b)–(c) show the draw-in pattern after the drawing process of the rectangular pan as simulated by Pam-Stamp for each of the predicted blank shapes. The draw-in patterns for all three rectangular pans matched in the corners regions quite well. The slip line field method, though, did not achieve the objective 1?in. flange in the side region, while the Romanovski and FAST_FORM3D methods achieved the 1?in. flange in the side regions relatively well. Further, only the FAST_FORM3D blank agrees in the corner/side transition regions. Moreover, the FAST_FORM3D blank has a better strain distribution and lower peak strain than Romanovski as can be seen in Fig. 6.
Fig. 5. Various blank shape predictions and Pam-Stamp simulation results for the rectangular pan.
(a) Three predicted blank shapes; (b) deformed slip line field blank; (c) deformed Romanovski blank; (d) deformed FAST_FORM3D blank.
Fig. 6. Comparison of strain distribution of various blank shapes using Pam-Stamp for the rectangular pan.
(a) Deformed Romanovski blank; (b) deformed FAST_FORM3D blank.
To continue this validation study, an industrial part from the Komatsu Ltd. was chosen and is shown in Fig. 7(a). We predicted an optimal blank geometry with FAST_FORM3D and compared it with the experimentally developed blank shape as shown in Fig. 7(b). As seen, the blanks are similar but have some differences.
Fig. 7. FAST_FORM3D simulation results for instrument cover validation.
(a) FAST_FORM3D's formability evaluation; (b) comparison of predicted and experimental blank geometries.
Next we simulated the stamping of the FAST_FORM3D blank and the experimental blank using Pam-Stamp. We compared both predicted geometries to the nominal CAD geometry (Fig. 8) and found that the FAST_FORM3D geometry was much more accurate. A nice feature of FAST_FORM3D is that it can show a “failure” contour plot of the part with respect to a failure limit curve which is shown in Fig. 7(a). In conclusion, FAST_FORM3D was successful at predicting optimal blank shapes for a laboratory and industrial parts. This indicates that FAST_FORM3D can be successfully used to assess formability issues of product designs. In the case of the instrument cover, many hours of trial and error experimentation could have been eliminated by using FAST_FORM3D and a better blank shape could have been developed.
Fig. 8. Comparison of FAST_FORM3D and experimental blank shapes for the instrument cover.
(a) Experimentally developed blank shape and the nominal CAD geometry; (b) FAST_FORM3D optimal blank shape and the nominal CAD geometry.
3. Die and process simulation – applications
In order to study the die design process closely, a cooperative study was conducted by Komatsu Ltd. of Japan and the ERC/NSM. A production panel with forming problems was chosen by Komatsu. This panel was the excavator's cabin, left-hand inner panel shown in Fig. 9. The geometry was simplified into an experimental laboratory die, while maintaining the main features of the panel. Experiments were conducted at Komatsu using the process conditions shown in Table 2. A forming limit diagram (FLD) was developed for the drawing-quality steel using dome tests and a vision strain measurement system and is shown in Fig. 10. Three blank holder forces (10, 30, and 50?ton) were used in the experiments to determine its effect. Incremental simulations of each experimental condition was conducted at the ERC/NSM using Pam-Stamp.
Fig. 9. Actual product – cabin inner panel.
Table 2. Process conditions for the cabin inner investigation
Fig. 10. Forming limit diagram for the drawing-quality steel used in the cabin inner investigation.
At 10?ton, wrinkling occurred in the experimental parts as shown in Fig. 11. At 30?ton, the wrinkling was eliminated as shown in Fig. 12. These experimental observations were predicted with Pam-stamp simulations as shown in Fig. 13. The 30?ton panel was measured to determine the material draw-in pattern. These measurements are compared with the predicted material draw-in in Fig. 14. Agreement was very good, with a maximum error of only 10?mm. A slight neck was observed in the 30?ton panel as shown in Fig. 13. At 50?ton, an obvious fracture occurred in the panel.
Fig. 11. Wrinkling in laboratory cabin inner panel, BHF=10?ton.
Fig. 12. Deformation stages of the laboratory cabin inner and necking, BHF=30?ton.
(a) Experimental blank; (b) experimental panel, 60% formed; (c) experimental panel, fully formed; (d) experimental panel, necking detail.
Fig. 13. Predication and elimination of wrinkling in the laboratory cabin inner.
(a) Predicted geometry, BHF=10?ton; (b) predicted geometry, BHF=30?ton.
Fig. 14. Comparison of predicted and measured material draw-in for lab cabin inner, BHF=30?ton.
Strains were measured with the vision strain measurement system for each panel, and the results are shown in Fig. 15. The predicted strains from FEM simulations for each panel are shown in Fig. 16. The predictions and measurements agree well regarding the strain distributions, but differ slightly on the effect of BHF. Although the trends are represented, the BHF tends to effect the strains in a more localized manner in the simulations when compared to the measurements. Nevertheless, these strain prediction show that Pam-Stamp correctly predicted the necking and fracture which occurs at 30 and 50?ton. The effect of friction on strain distribution was also investigated with simulations and is shown in Fig. 17.
Fig. 15. Experimental strain measurements for the laboratory cabin inner.
(a) measured strain, BHF=10?ton (panel wrinkled); (b) measured strain, BHF=30?ton (panel necked); (c) measured strain, BHF =50?ton (panel fractured).
Fig. 16. FEM strain predictions for the laboratory cabin inner.
(a) Predicted strain, BHF=10?ton; (b) predicted strain, BHF=30?ton; (c) predicted strain, BHF=50?ton.
Fig. 17. Predicted effect of friction for the laboratory cabin inner, BHF=30?ton.
(a) Predicted strain, μ=0.06; (b) predicted strain, μ=0.10.
A summary of the results of the comparisons is included in Table 3. This table shows that the simulations predicted the experimental observations at least as well as the strain measurement system at each of the experimental conditions. This indicates that Pam-Stamp can be used to assess formability issues associated with the die design.
Table 3. Summary results of cabin inner study
4. Blank holder force control – applications
The objective of this investigation was to determine the drawability of various, high performance materials using a hemispherical, dome-bottomed, deep drawn cup (see Fig. 18) and to investigate various time variable blank holder force profiles. The materials that were investigated included AKDQ steel, high strength steel, bake hard steel, and aluminum 6111 (see Table 4). Tensile tests were performed on these materials to determine flow stress and anisotropy characteristics for analysis and for input into the simulations (see Fig. 19 and Table 5).
Fig. 18. Dome cup tooling geometry.
Table 4. Material used for the dome cup study
Fig. 19. Results of tensile tests of aluminum 6111, AKDQ, high strength, and bake hard steels.
(a) Fractured tensile specimens; (b) Stress/strain curves.
Table 5. Tensile test data for aluminum 6111, AKDQ, high strength, and bake hard steels
It is interesting to note that the flow stress curves for bake hard steel and AKDQ steel were very similar except for a 5% reduction in elongation for bake hard. Although, the elongations for high strength steel and aluminum 6111 were similar, the n-value for aluminum 6111 was twice as large. Also, the r-value for AKDQ was much bigger than 1, while bake hard was nearly 1, and aluminum 6111 was much less than 1.
The time variable BHF profiles used in this investigation included constant, linearly decreasing, and pulsating (see Fig. 20). The experimental conditions for AKDQ steel were simulated using the incremental code Pam-Stamp. Examples of wrinkled, fractured, and good laboratory cups are shown in Fig. 21 as well as an image of a simulated wrinkled cup.
Fig. 20. BHF time-profiles used for the dome cup study.
(a) Constant BHF; (b) ramp BHF; (c) pulsating BHF.
Fig. 21. Experimental and simulated dome cups.
(a) Experimental good cup; (b) experimental fractured cup; (c) experimental wrinkled cup; (d) simulated wrinkled cup.
Limits of drawability were experimentally investigated using constant BHF. The results of this study are shown in Table 6. This table indicates that AKDQ had the largest drawability window while aluminum had the smallest and bake hard and high strength steels were in the middle. The strain distributions for constant, ramp, and pulsating BHF are compared experimentally in Fig. 22 and are compared with simulations in Fig. 23 for AKDQ. In both simulations and experiments, it was found that the ramp BHF trajectory improved the strain distribution the best. Not only were peak strains reduced by up to 5% thereby reducing the possibility of fracture, but low strain regions were increased. This improvement in strain distribution can increase product stiffness and strength, decrease springback and residual stresses, increase product quality and process robustness.
Table 6. Limits of drawability for dome cup with constant BHF
Fig. 22. Experimental effect of time variable BHF on engineering strain in an AKDQ steel dome cup.
Fig. 23. Simulated effect of time variable BHF on true strain in an AKDQ steel dome cup.
Pulsating BHF, at the frequency range investigated, was not found to have an effect on strain distribution. This was likely due to the fact the frequency of pulsation that was tested was only 1?Hz. It is known from previous experiments of other researchers that proper frequencies range from 5 to 25?Hz [3]. A comparison of load-stroke curves from simulation and experiments are shown in Fig. 24 for AKDQ. Good agreement was found for the case where μ=0.08. This indicates that FEM simulations can be used to assess the formability improvements that can be obtained by using BHF control techniques.
Fig. 24. Comparison of experimental and simulated load-stroke curves for an AKDQ steel dome cup.
5 Conclusions and future work
In this paper, we evaluated an improved design process for complex stampings which involved eliminating the soft tooling phase and incorporated the validation of product and process using one-step and incremental FEM simulations. Also, process improvements were proposed consisting of the implementation of blank holder force control to increase product quality and process robustness.
Three separate investigations were summarized which analyzed various stages in the design process. First, the product design phase was investigated with a laboratory and industrial validation of the one-step FEM code FAST_FORM3D and its ability to assess formability issues involved in product design. FAST_FORM3D was successful at predicting optimal blank shapes for a rectangular pan and an industrial instrument cover. In the case of the instrument cover, many hours of trial and error experimentation could have been eliminated by using FAST_FORM3D and a better blank shape could have been developed.
Second, the die design