蓋體沖壓模具設(shè)計(jì)[工藝]【含15張圖紙】

喜歡就充值下載吧。資源目錄里展示的全都有，下載后全都有請(qǐng)放心下載，原稿可自行編輯修改=【QQ：1304139763可咨詢交流】喜歡就充值下載吧。喜歡就充值下載吧。資源目錄里展示的全都有，下載后全都有請(qǐng)放心下載，原稿可自行編輯修改=【QQ：1304139763可咨詢交流】喜歡就充值下載吧。喜歡就充值下載吧。資源目錄里展示的全都有，下載后全都有請(qǐng)放心下載，原稿可自行編輯修改=【QQ：1304139763可咨詢交流】喜歡就充值下載吧。 北華航天工業(yè)學(xué)院畢業(yè)論文摘 要分析了蓋體的結(jié)構(gòu)和成形工藝，計(jì)算了毛坯尺寸和沖壓力。為了提高蓋體的生產(chǎn)效率，設(shè)計(jì)了集兩工序?yàn)橐惑w的落料拉深復(fù)合模的結(jié)構(gòu)，經(jīng)過工藝分析、結(jié)構(gòu)設(shè)計(jì)，論證了其可能性，保證了制品的質(zhì)量。在模具設(shè)計(jì)中,為了提高速度和效率,充分利用已經(jīng)掌握的知識(shí)和資源。利用Pro/E曲面設(shè)計(jì)功能快速求出曲面的面積,通過計(jì)算驗(yàn)證結(jié)果。利用沖模設(shè)計(jì)手冊(cè)快速設(shè)計(jì)沖壓模具,并對(duì)模具的強(qiáng)度進(jìn)行檢驗(yàn)。實(shí)踐證明,確實(shí)提高了設(shè)計(jì)的速度和效率。本模具設(shè)計(jì)中,由于卸料力較大,采用了固定卸料板卸料力較大的優(yōu)點(diǎn)解決了這一問題。關(guān)鍵詞 落料 拉深 復(fù)合模 AbstractCover of the structure and forming process were analyzed, calculate the size of rough-and pressure. In order to cover the increased production efficiency, the set design process as one of the two-and-blank drawing of the model structure, the process analysis, structural design, and demonstrated its potential to ensure the quality of the products. In the mould design, in order to improve the speed and efficiency, should make full use of available knowledge and resources. Use of Pro / E surface design features of the surface area of rapid obtained by calculating verify the results. Die Design Manual use of rapid design stamping die and mould the strength test. Practice has proved that, indeed improve the design of the speed and efficiency. The die design, since the unloading of the larger, fixed by the board unloading which unloading of the advantages of greater resolve this issue.Key words cut tandem compound die 目 錄摘 要Abstract第1章 緒 論1第2章 設(shè)計(jì)題目2第3章 工藝分析33.1 技術(shù)分析33.1.1 沖裁的結(jié)構(gòu)工藝性33.1.2 拉深的結(jié)構(gòu)工藝性33.2 經(jīng)濟(jì)分析43.2.1 沖壓件成本分析43.2.2 降低制造成本的措施53.3 蓋體的工藝分析63.3.1 材料63.3.2 零件結(jié)構(gòu)63.3.3 尺寸精度6第4章 制定工藝方案74.1 工藝方案的分析74.1.1 修邊余量74.1.2 計(jì)算毛坯尺寸74.1.3 確定是否用壓邊圈74.1.4 確定拉深次數(shù)84.2 工藝方案的確定8第5章 工藝計(jì)算105.1 材料排樣及材料利用率的計(jì)算105.1.1 材料排樣的選用原則105.1.2 確定板料規(guī)格和裁料方式105.2 沖壓力的計(jì)算及設(shè)備的選擇115.2.1 落料115.2.2 拉深115.2.3 總沖壓力125.2.4 沖壓設(shè)備的選擇125.3 模具壓力中心的計(jì)算145.4 模具刃口尺寸和公差確定155.4.1 坯料沖裁間隙的確定155.4.2 落料刃口尺寸的計(jì)算165.4.3 拉深工序工作部分的尺寸及間隙16第6章 模具結(jié)構(gòu)合理性分析196.1 模具結(jié)構(gòu)圖196.2 模具的工作過程20結(jié) 論21致 謝22參考文獻(xiàn)23北華航天工業(yè)學(xué)院畢業(yè)論文第1章 緒 論作為一個(gè)即將畢業(yè)的材料專業(yè)模具方向?qū)W生來說，年專業(yè)知識(shí)的學(xué)習(xí)，為以后從事沖壓模具設(shè)計(jì)打下了良好的基礎(chǔ)。同時(shí)在校時(shí)了解模具行業(yè)的發(fā)展趨勢(shì)也是很有必要的,它有助于我們把握自己的學(xué)習(xí)方向，不斷提高自己的專業(yè)素養(yǎng)。近年中國經(jīng)濟(jì)高速增長。各行各業(yè)高速發(fā)展，帶動(dòng)了模具市場(chǎng)的持續(xù)高速發(fā)展。模具市場(chǎng)中最大的板塊是汽車。模具市場(chǎng)中第二大板塊是電子及信息產(chǎn)業(yè)。中國的玩具、自行車、微波爐分別占全世界市場(chǎng)份額的70%、60%和50%。中國的影印機(jī)、個(gè)人電腦、電視機(jī)和空調(diào)器分別占全世界市場(chǎng)份額的2/3、2/5和1/3。冰箱也已占了20%。這些產(chǎn)品制造業(yè)都是模具的大用戶。在此形勢(shì)之下，中國的模具工業(yè)高速發(fā)展是必然所趨。 隨著中國加入WTO，在機(jī)遇與挑戰(zhàn)并存中，中國模具工業(yè)面臨的形勢(shì)是機(jī)遇大于挑戰(zhàn)。因而，一方面是模具的進(jìn)出口高速發(fā)展，另一方面是外資大量涌入中國的模具行業(yè)。外資大量涌入中國模具行業(yè)產(chǎn)生兩方面效應(yīng)。一是外資不僅帶來資金，也帶來了技術(shù)與市場(chǎng)；二是外資企業(yè)在市場(chǎng)中處于優(yōu)勢(shì)地位，給國內(nèi)民族工業(yè)帶來了很大的競爭壓力。這兩方面效應(yīng)都促使中國模具工業(yè)的快速發(fā)展，包括模具產(chǎn)品的數(shù)量、質(zhì)量、品種和水平?，F(xiàn)代模具工業(yè)有“不衰亡工業(yè)”之稱。世界模具市場(chǎng)總體上供不應(yīng)求，市場(chǎng)需求量維持在600億至650億美元，同時(shí)，我國的模具產(chǎn)業(yè)也迎來了新一輪的發(fā)展機(jī)遇。近幾年，我國模具產(chǎn)業(yè)總產(chǎn)值保持13%的年增長率（據(jù)不完全統(tǒng)計(jì)，2004年國內(nèi)模具進(jìn)口總值達(dá)到600多億，同時(shí)，有近200個(gè)億的出口），2005年模具產(chǎn)值超過600億元，模具及模具標(biāo)準(zhǔn)件出口將從每年9000多萬美元增長到2005年的2億美元左右。質(zhì)量、周期、價(jià)格、服務(wù)，是模具銷售的四大要素。在目前的模具市場(chǎng)中，周期越來越重要。模具材料不斷漲價(jià)，工資不斷上升，模具價(jià)格總體上卻是不漲反降，因此模具生產(chǎn)企業(yè)利潤空間被壓縮。為了生存與發(fā)展，近年模具企業(yè)更加注重技術(shù)進(jìn)步和管理改善。這些也都促進(jìn)了模具市場(chǎng)的健康發(fā)展。由于中低檔模具競爭加劇，中高檔模具市場(chǎng)空間相對(duì)較大，因此，不斷提高模具產(chǎn)品的技術(shù)含量，已是許多模具企業(yè)的共同目標(biāo)。這樣，大型、精密、復(fù)雜、長壽命等技術(shù)含量高的中高檔模具的發(fā)展速度自然也就快于模具行業(yè)的總體發(fā)展速度。從而促進(jìn)了模具市場(chǎng)的產(chǎn)品和技術(shù)結(jié)構(gòu)向著合理化方向發(fā)展，致使模具市場(chǎng)更加繁榮。未來模具技術(shù)的發(fā)展趨勢(shì)：（1）模具產(chǎn)品發(fā)展將大型化精密化。（2）快速經(jīng)濟(jì)模具的前景十分廣闊。（3）模具標(biāo)準(zhǔn)件的應(yīng)用將日漸廣泛。（4）在模具設(shè)計(jì)制造中將全面推廣CAD/CAM/CAE技術(shù)。（5）模具高速掃描及數(shù)字化系統(tǒng)將發(fā)揮更大的作用。（6）模具研磨拋光將向自動(dòng)化、智能化方向發(fā)展。（7）模具自動(dòng)加工系統(tǒng)的研制和發(fā)展。第2章 設(shè)計(jì)題目產(chǎn)品名稱：蓋體材料：LF21（M），厚度t=1.2mm。下圖為零件的二維CAXA圖： 圖2-1 蓋體零件圖第3章 工藝分析工件的工藝性是指工件對(duì)沖壓加工工藝的適應(yīng)性，它是從沖壓加工角度對(duì)產(chǎn)品設(shè)計(jì)提出的工藝要求。工藝分析包括技術(shù)和經(jīng)濟(jì)兩方面內(nèi)容。在技術(shù)方面，根據(jù)產(chǎn)品圖樣，主要分析該沖壓件的形狀特點(diǎn)、尺寸大小、精度要求和材料性能等因素是否符合沖壓加工的要求。在經(jīng)濟(jì)方面，主要根據(jù)沖壓件的生產(chǎn)批量，分析產(chǎn)品成本，闡明采用沖壓加工可取得的經(jīng)濟(jì)效益。3.1 技術(shù)分析3.1.1 沖裁的結(jié)構(gòu)工藝性 （1）沖裁件的外形或內(nèi)孔應(yīng)避免尖銳的清角，在各直線或曲線的連接處，除屬于無廢料沖裁或采用鑲拼模結(jié)構(gòu)外，宜有適當(dāng)?shù)膱A角，其半徑的最小值如表1所示：本次沖裁為落料一圓形件。（2）用普通沖裁模沖制的零件，其斷面與零件表面并不垂直，并有明顯區(qū)域性特征。采用合理使用間隙沖裁模沖制的零件，光亮區(qū)域約占斷面厚度的30%；凹模側(cè)有明顯的塌角，凸模側(cè)有高度不小于0.05mm的毛刺；外形有一定程度的拱曲。（3）凡產(chǎn)品圖紙上未注公差的尺寸均屬于未注公差尺寸。在計(jì)算凸模和凹模時(shí)，沖壓件未注公差尺寸的極限偏差數(shù)值通常按GB1800-79IT14級(jí)。3.1.2 拉深的結(jié)構(gòu)工藝性（1）拉深件的形狀應(yīng)盡量簡單、對(duì)稱。（2）拉深件各部分尺寸比例要恰當(dāng)。拉深件高度不宜太大，一般控制在h=2d(h為拉深件高度，d為拉深件直徑)。拉深件凸緣寬度不宜太寬，一般控制在如下范圍：d+12t=d凸h1/d1 故不能一次拉深成形。材料的首次拉深極限為0.520.55，以后各次為0.700.75。選定m1=0.58 m2=0.722 m2=m/(m1m2)=0.298/(0.580.722)=0.71d1=m1D=0.5898=57mmh1=9.73mmm2=0.724 查得m2=0.700.75d2=m2d1=0.72457=41.2mmh2=22.86mm 至此，拉深成筒形件。m3=0.71 查得m3=0.700.75d2=m2d1=0.7141.2=29.2mmh2=36mm 綜上所述，完成錐形件的拉深需三次。4.2 工藝方案的確定在沖壓工藝性分析的基礎(chǔ)上，找出工藝與模具設(shè)計(jì)的特點(diǎn)與難點(diǎn)，根據(jù)實(shí)際情況提出各種可能的沖壓工藝方案，內(nèi)容包括工序性質(zhì)、工序數(shù)目、工序順序及組合方式等。有時(shí)同一種沖壓零件也可能存在多個(gè)可行的沖壓工藝方案，通常每種方案各有優(yōu)缺點(diǎn)，應(yīng)從產(chǎn)品質(zhì)量、生產(chǎn)效率、設(shè)備占用情況、模具制造的難易程度和壽命高低、生產(chǎn)成本、操作方便與安全程度等方面進(jìn)行綜合分析、比較，確定出適合于現(xiàn)有生產(chǎn)條件的最佳方案。 初步分析可以知道蓋體的沖壓成形需要多道工序:落料，筒形拉深，錐體拉深，翻孔，整形，沖孔及切邊，成形工藝方案十分重要?？紤]到生產(chǎn)批量大,因此制定應(yīng)在生產(chǎn)合格零件的基礎(chǔ)上,盡量提高生產(chǎn)效率,降低生產(chǎn)成本.要提高生產(chǎn)效率,就應(yīng)該盡量復(fù)合能復(fù)合的工序,但復(fù)合程度太高,模具結(jié)構(gòu)復(fù)雜,而且各零件在動(dòng)作時(shí)要求相互不干涉,準(zhǔn)確可靠.這就要求模具的制造應(yīng)有較高的精度,從而模具的制造成本也就提高了,制造周期延長,維修不如單工序模簡便.因此端蓋的沖壓成形主要有以下幾種工藝方案:方案一:(1)落料 (2)拉深 (3)預(yù)沖孔（4）翻孔（5）整形（6）沖孔（7）切邊方案二:(1)落料拉深復(fù)合模 (2)二次拉深及三次拉深（3）沖孔翻孔復(fù)合模 （4）整形（5）沖孔（6）切邊方案一復(fù)合程度低,模具結(jié)構(gòu)簡單、安裝調(diào)試容易,但生產(chǎn)道次多、生產(chǎn)效率低不適合大批量生產(chǎn)。方案二采用落料、拉深復(fù)合工序.由于采用落料、拉深復(fù)合模,即可在一次沖壓行程中完成,生產(chǎn)效率提高一倍,節(jié)省了人力、電力和工序間的搬運(yùn)工作,而且在同一工位上沖孔無需重新定位,從而使沖壓工件的位置精度得到提高。經(jīng)過理論計(jì)算,可以采用落料、拉深復(fù)合模成形，選用方案二進(jìn)行生產(chǎn)。第5章 工藝計(jì)算5.1 材料排樣及材料利用率的計(jì)算排樣是指沖裁零件在條料、帶料或板料上布置的方法。合理有效的排樣在于保證在最低的材料消耗和高生產(chǎn)率的條件下，得到符合設(shè)計(jì)技術(shù)要求的工件。在沖壓生產(chǎn)過程中，保證很低的廢料百分率是現(xiàn)代沖壓生產(chǎn)最重要的技術(shù)指標(biāo)之一。在沖壓工作中，沖壓件材料消耗費(fèi)用可達(dá)總成本的60%75%，每降低1%的沖壓廢料，將會(huì)使成本降低0.4%0.5%。合理利用材料是降低成本的有效措施，尤其在成批和大量生產(chǎn)中，沖壓零件的年產(chǎn)量達(dá)數(shù)十萬件，甚至數(shù)百萬件，材料合理利用的經(jīng)濟(jì)效果更為突出。5.1.1 材料排樣的選用原則（1）沖裁小工件或某種工件需要窄帶料時(shí)，應(yīng)沿板料順長方向進(jìn)行排樣，符合材料規(guī)格及工藝要求。（2）沖裁彎曲件毛坯時(shí)，應(yīng)考慮板料的軋制方向。（3）沖件在條（帶）料上的排樣，應(yīng)考慮沖壓生產(chǎn)率、沖模耐用度、沖模結(jié)構(gòu)是否簡單和操的方便與安全等。該零件采用落料拉深復(fù)合模，毛坯形狀為圓形，為便于送料和設(shè)計(jì)，采用單排方案。搭邊可用于補(bǔ)償定位誤差，并可使條料保持有一定的剛度，便于送料。搭邊是廢料，所以應(yīng)盡量取小，但過小的搭邊容易擠進(jìn)凹模，增加刃口磨損，影響模具壽命，并且也影響沖裁件的剪切表面質(zhì)量。排料搭邊數(shù)值大小不僅與材料性能和厚度、沖件形狀和尺寸大小有關(guān)，而且與沖裁模具選用不同卸料方式有關(guān)。一般來說，搭邊值是由經(jīng)驗(yàn)確定的。查表7，工件間a=0.8側(cè)面a1=1.0。5.1.2 確定板料規(guī)格和裁料方式根據(jù)條料的寬度尺寸，選擇合適的板料規(guī)格，使剩余的邊料越小越好。該零件寬度用料為100mm，以選擇1000mm100mm1.2mm的板料規(guī)格為宜。一張板料上總的材料利用率： （5-1）5.2 沖壓力的計(jì)算及設(shè)備的選擇5.2.1 落料沖裁時(shí)，工件或廢料從凸模上取下來的力叫卸料力，從凹模內(nèi)將工件或廢料順著沖裁的方向推出的力叫推件力，逆沖裁方向頂出的力叫頂件力。目前多以經(jīng)驗(yàn)公式計(jì)算：采用平刃口凸模和凹模沖裁時(shí)，沖裁力F0=Lt （5-2） 式中，L沖裁件周長（） T材料厚度（）材料的抗剪強(qiáng)度（MPa）考慮沖裁厚度不一致，模具刃口的磨損、凸凹模間隙的波動(dòng)、材料性能的變化等因素，實(shí)際沖裁力還須增加30%。故F沖=1.3F0=1.3 Lt。F沖=1.3F0=1.3 Lt （5-3） =1.3p981.2mm125MPa =60KNF卸、F推、F頂是由壓力機(jī)和模具的卸料、頂件裝置獲得。影響這些力的因素主要有材料的力學(xué)性能、材料的厚度、模具的間隙、凸凹模表面粗糙度、零件形狀和尺寸以及潤滑情況。實(shí)際生產(chǎn)中常用下列經(jīng)驗(yàn)公式計(jì)算：F卸=K卸F沖 （5-4）F推=K推F沖 （5-5）查表8知，卸料力、推件力的系數(shù)K卸=0.05，K推=0.055。因而F卸=0.0560KN=3KN F推=0.05560KN=3.3KN5.2.2 拉深 壓邊圈的壓力必須適當(dāng)，如果過大，就要增加拉深力，因而會(huì)使工件拉裂，而壓邊圈的壓力過低就會(huì)使工件的邊壁或凸緣起皺。 壓邊力的計(jì)算公式為： （5-6） 式中 D （平毛坯直徑）=98 d1 （拉深件直徑）=58mm r凹（凹模圓角半徑）=2 p （單邊壓力值）查表10，知P=1.5MPa把以上數(shù)據(jù)代入上式。得壓邊力 采用壓邊圈的圓筒形件：F=Kp （5-7） 式中拉深件的直徑（） 材料厚度（） 材料的抗拉強(qiáng)度（MPa）查表11，拉深系數(shù)1=0.58，所以k取0.68 將K0.68，d158mm，1.2mm、105MPa代入上式，得 F拉0.68p 581.2mm105MPa 15.604KN 二次拉深力計(jì)算為: F拉=0.683.1441.21.2mm105MPa =11.08KN 壓邊力為: =1.555KN三次拉深力計(jì)算為: F拉=0.683.1429.21.2mm105MPa =7.856KN5.2.3 總沖壓力復(fù)合?？偟臎_壓力：5.2.4 沖壓設(shè)備的選擇5.2.4.1 壓力機(jī)類型的選擇 沖壓設(shè)備的選擇是工藝設(shè)計(jì)中的一項(xiàng)重要內(nèi)容，它直接關(guān)系到設(shè)備的合理使用、安全、產(chǎn)品質(zhì)量、模具壽命、生產(chǎn)效率和成本等一系列重要問題。沖壓設(shè)備的選擇包括兩個(gè)方面：類型及規(guī)格。首先，應(yīng)根據(jù)所要完成工序的工藝性質(zhì)，批量大小，工件的幾何尺寸和精度等選定壓力機(jī)類型。沖壓生產(chǎn)中常用的是曲柄壓力機(jī)和液壓機(jī)，它們?cè)谛阅芊矫娴谋容^見表12。對(duì)于中小型沖裁件、彎曲件或淺拉深件多用具有C形床身的開式曲柄壓力機(jī)。雖然開式壓力機(jī)的剛度差，并且由于床身的變形而破壞了沖模的間隙分布，降低了沖模的壽命和裁件的質(zhì)量。但是，它卻具有操作空間三面敞開，操作方便，容易安裝機(jī)械化的附屬設(shè)備和成本低廉等優(yōu)點(diǎn)，目前仍是中小件生產(chǎn)的主要設(shè)備。所以本模具采用開式曲柄壓力機(jī)。5.2.4.2 壓力機(jī)規(guī)格的確定 在壓力機(jī)的類型選定之后，應(yīng)根據(jù)變形力的大小，沖壓件尺寸和模具尺寸來確定壓力機(jī)的規(guī)格。在復(fù)合沖壓中，工序力的計(jì)算和其它復(fù)雜的加工過程一樣，可按時(shí)間分為若干階段分別計(jì)算。求出某階段所完成各種工藝力的總和及該階段的輔助負(fù)荷，二者相加即為該階段的工序力。為安全起見，防止設(shè)備的過載，可按公稱壓力F壓（1.61.8）F總的原則選取壓力機(jī)。壓力機(jī)滑塊行程大小，應(yīng)保證成形零件的取出和方便毛坯的放進(jìn)。在沖壓工藝中，拉深和彎曲工序一般需要較大的行程。對(duì)于拉深工序所用壓力機(jī)的行程，至少應(yīng)為成品零件高度的兩倍以上，一般取2.5倍。壓力機(jī)的裝模高度是指滑塊處于下死點(diǎn)位置時(shí)，滑塊下表面到工作墊板上表面的距離。模具的閉合高度是指工作行程終了時(shí)，模具上模座上表面與下模座下表面之間的距離。壓力機(jī)的閉合高度是裝模高度與墊板厚度之和。大多數(shù)壓力機(jī)，其連桿長度是可以調(diào)節(jié)的，也就是說壓力機(jī)的裝模高度是可以調(diào)整的。設(shè)計(jì)模具時(shí)，必須使模具的閉合高度介于壓力機(jī)的最大裝模高度與最小裝模高度之間。工作臺(tái)面和滑塊底面尺寸應(yīng)大于沖模的平面尺寸，并還留有安裝固定模具的余地。一般壓力機(jī)臺(tái)面應(yīng)大于模具底座尺寸5070mm以上。工作臺(tái)和滑塊的形式應(yīng)充分考慮沖壓工藝的需要必須與模具的打料裝置，出料裝置及卸料裝置等的結(jié)構(gòu)相適應(yīng)。在壓力機(jī)的滑塊和工作臺(tái)上安裝一副或數(shù)副模具，加工時(shí)上、下模要有正確的相對(duì)運(yùn)動(dòng)，這是一切沖壓工藝的共同要求。壓力機(jī)的精度主要包括工作臺(tái)面的平面度、滑塊下平面的平面度、工作臺(tái)面與滑塊下平面的平行度、滑塊行程同工作臺(tái)面的垂直度及滑塊中心孔同滑塊行程的平行度等。壓力機(jī)精度的高低對(duì)沖壓工序有很大的影響。精度高，則沖壓件質(zhì)量也高，沖模的使用壽命長。反之，壓力機(jī)精度低，不僅沖壓件質(zhì)量低，且模具壽命短。例如若滑塊行程與工作臺(tái)的垂直度差，將導(dǎo)致上、下模的同軸度降低，沖模刃口易損傷。壓力機(jī)的精度對(duì)沖裁加工的影響較之其它加工工序明顯。參照開式雙柱固定臺(tái)壓力機(jī)基本參數(shù)（JA21-35）可選取公稱壓力為350KN的開式固定臺(tái)壓力機(jī)。該壓力機(jī)與模具設(shè)計(jì)有關(guān)系的參數(shù)為：公稱壓力：350KN滑塊行程：130最大閉合高度：280閉合高度調(diào)節(jié)量：60工作臺(tái)尺寸：380610模柄孔尺寸：50705.3 模具壓力中心的計(jì)算為了保證壓力機(jī)和模具正常地工作，必須使沖模的壓力中心與壓力機(jī)滑塊中心線相重合，否則在沖壓時(shí)會(huì)使沖模與壓力機(jī)滑塊歪斜，引起凸、凹模間隙不均和導(dǎo)向零件加速磨損，造成刃口和其它零件的損壞，甚至還會(huì)引起壓力機(jī)導(dǎo)軌磨損，影響壓力機(jī)精度。形狀簡單而對(duì)稱的工件，如圓形，其沖裁時(shí)的壓力中心與工件的幾何中心重合。 圖5-1 如圖6所示按比例畫出工件的形狀，選定坐標(biāo)系XOY，因沖壓件對(duì)稱于X軸、Y軸，故模具的壓力中心在工件的幾何中心，即圖中的O點(diǎn)。5.4 模具刃口尺寸和公差確定5.4.1 坯料沖裁間隙的確定沖裁間隙是直接關(guān)系到?jīng)_件斷面質(zhì)量、尺寸精度、模具壽命和力能消耗的重要工藝參數(shù)。沖裁間隙數(shù)值，主要與材料牌號(hào)、供應(yīng)狀態(tài)和厚度有關(guān)，但由于各種沖壓件對(duì)其斷面質(zhì)量和尺寸精度的要求不同，以及生產(chǎn)條件的差異，在生產(chǎn)實(shí)踐中就很難有一種統(tǒng)一的間隙數(shù)值，而應(yīng)區(qū)別情況，分別對(duì)待，在保證沖件斷面質(zhì)量和尺寸精度的前提下，使模具壽命最高。沖裁斷面應(yīng)平直、光潔、圓角?。还饬翈?yīng)有一定的比例，毛刺較小，沖裁件表面應(yīng)盡可能平整，尺寸應(yīng)在圖樣規(guī)定的公差范圍之內(nèi)。影響沖裁件質(zhì)量的因素有：凸、凹模間隙值大小及其分布的均勻性，模具刃口鋒利狀態(tài)，模具結(jié)構(gòu)與制造精度、材料性能等。其中，間隙值大小與分布的均勻程度是主要因素。沖裁件的尺寸精度是指沖裁件實(shí)際尺寸與基本尺寸的差值，差值越小，精度越高。該差值包括兩方面的偏差，一是沖裁件相對(duì)于凸模或凹模尺寸之偏差，二是模具本身的制造偏差。沖裁件對(duì)于凸?；虬寄３叽绲钠?。主要是由于沖裁過程中，材料受到拉伸、擠壓、彎曲等作用而引起的變形，在工件脫模后產(chǎn)生的彈性恢復(fù)造成的。偏差值可能是正的，也可能是負(fù)的。影響這一偏差值的因素主要是凸、凹模間隙。當(dāng)間隙值較大時(shí)，材料受拉伸作用增大，沖裁完畢后，因材料的彈性恢復(fù)，沖件尺寸向?qū)嶓w方向收縮，使落料件尺寸小于凹模尺寸，而沖孔件的孔徑則大于凸模尺寸；當(dāng)間隙較小時(shí)，材料的彈性恢復(fù)使落料件尺寸增大，而沖孔件的孔徑則變小。沖裁件的尺寸變化量的大小還與材料性能、厚度、軋制方向、沖件形狀等因素有關(guān)。模具制造精度及模具刃口狀態(tài)也會(huì)影響沖裁件質(zhì)量。沖裁模具的壽命是以沖出合格制品的沖裁次數(shù)來衡量的，可再分為兩次刃磨間的壽命與全磨損后總的壽命。 在沖裁過程中，模具刃口處所受的壓力非常大使模具刃口和板材的接觸面之間出現(xiàn)局部附著現(xiàn)象，產(chǎn)生附著磨損，其磨損量與接觸壓力、相對(duì)滑動(dòng)距離成正比，與材料屈服強(qiáng)度成反比。它被認(rèn)為是模具磨損的主要形式。當(dāng)間隙減小時(shí)，接觸壓力(垂直力、側(cè)壓力、摩擦力)會(huì)增大，摩擦距離增長，摩擦發(fā)熱嚴(yán)重，導(dǎo)致模具磨損加劇，使模具與材料之間產(chǎn)生粘結(jié)現(xiàn)象還會(huì)引起刃口的壓縮疲勞破壞，使之崩刃。間隙過大時(shí)板料彎曲拉伸相對(duì)增加，使模具刃口端面上的正壓力增大，容易產(chǎn)生崩刃或產(chǎn)生塑性變形，使磨損加劇?？梢婇g隙過小與過大都會(huì)導(dǎo)致模具壽命降低。因此，間隙合適或適當(dāng)增大模具問隙，可使凸、凹模側(cè)面與材料間摩擦減小，并減緩間隙不均勻的不利因素，從而提高模具壽命。增大間隙可以降低沖裁力，而小間隙則使沖裁力增大。當(dāng)間隙合理時(shí)，上下裂紋重合，最大剪切力較小。而小間隙時(shí)，材料所受力矩和拉應(yīng)力減小，壓應(yīng)力增大，材料不易產(chǎn)生撕裂，上下裂紋不重合又產(chǎn)生二次剪切，使沖裁力、沖裁功有所增大；增大間隙時(shí)材料所受力矩與拉應(yīng)力增大，材料易于剪裂分離，故最大沖裁力有所減小，如對(duì)沖裁件質(zhì)量要求不高，為降低沖裁力、減少模具磨損，傾向于取偏大的沖裁間隙。查沖裁模初始雙面間隙表3-4知：落料模刃口始用間隙Zmin=0.084，ZMAX=0.108。5.4.2 落料刃口尺寸的計(jì)算在確定沖模凸模和凹模工作部分尺寸時(shí)，必須遵循以下幾項(xiàng)原則：（1）根據(jù)落料的特點(diǎn)，落料件的尺寸取決于凹模尺寸，因此落料模應(yīng)先決定凹模尺寸，用減小凸模尺寸來保證合理間隙。（2）根據(jù)刃口的磨損規(guī)律，刃口磨損后尺寸變大，其刃口的基本尺寸應(yīng)取接近或等于工件的最小極限尺寸；刃口磨損后尺寸減小，應(yīng)取接近或等于工件的最大極限尺寸。（3）考慮工件精度與模具精度間的關(guān)系，在選擇模具刃口制造公差時(shí)，既要保證工件的精度要求，又能保證有合理的間隙數(shù)值。一般沖模精度較工件精度高23級(jí)。97-10的凸凹模制造公差查表得：凸=0.030、凹=0.045，凸凹模采用分開加工的方法，查表得：X=0.5 （5-9） （5-10）5.4.3 拉深工序工作部分的尺寸及間隙5.4.3.1 凸模和凹模的間隙拉深模間隙是指單面間隙。間隙的大小對(duì)拉深力、拉深件的質(zhì)量、拉深模的壽命都有影響。若Z值太小，凸緣區(qū)變厚的材料通過間隙時(shí)，校直與變形的阻力增加，與模具表面間的摩擦、磨損嚴(yán)重，使拉深力增加，零件變薄嚴(yán)重，甚至拉破，模具壽命降低。間隙小時(shí)得到的零件 側(cè)壁平直而光滑，質(zhì)量較好，精度較高。間隙過大時(shí)，對(duì)毛坯的校直和擠壓作用減小，拉深力降低，模具的壽命提高，但零件的質(zhì)量變差，沖出的零件側(cè)壁不直。因此拉深模的間隙值也應(yīng)合適，確定Z時(shí)要考慮壓邊狀況、拉深次數(shù)和工件精度等。其原則是：既要考慮板料本身的公差，又要考慮板料的增厚現(xiàn)象，間隙一般都比毛坯厚度略大一些。采用壓邊拉深時(shí)其值可按下式計(jì)算： Z=1.1t=1.32則拉深模的間隙2Z=2.64。5.4.3.2 拉深模的圓角半徑 （1）t/D=1.2/97=0.01240.10.3，當(dāng)工件直徑d20mm時(shí),rd=0.039d+2,可取圓角半徑為2.5mm。 （2）凸模的圓角半徑及尺寸公差等于工件的內(nèi)圓角半徑。5.4.3.3 工作部分尺寸凸模和凹模的尺寸及公差應(yīng)按零件的要求來確定，由于要求外形尺寸，因此以凹模設(shè)計(jì)為準(zhǔn)。查表得：凸=0.03、凹=0.05凹模部分 （5-11）凸模部分 （5-12） 二次拉深模具工作部分尺寸:凹模部分 （5-13） 凸模部分 （5-14） 三次拉深模具工作部分尺寸:凹模部分 （5-13） 凸模部分第6章 模具結(jié)構(gòu)合理性分析6.1 模具結(jié)構(gòu)圖 圖6-1 模具圖6.2 模具的工作過程1)準(zhǔn)備工作:將板料順著檔料銷導(dǎo)向滑動(dòng)，手工送料到全部工位后讓其在步進(jìn)電動(dòng)機(jī)的帶動(dòng)下自動(dòng)送料。2)沖床滑塊帶動(dòng)上模從最高點(diǎn)開始向下運(yùn)動(dòng)。3)上模繼續(xù)下行,導(dǎo)柱在導(dǎo)套滑動(dòng)，對(duì)上模導(dǎo)向起定位作用。4)隨著上模下行，板料被壓向下運(yùn)動(dòng)。卸料板壓著板料下行,板料碰到凹模。5)板料接觸凹模時(shí)卸料板停止運(yùn)動(dòng),沖床滑塊繼續(xù)向下運(yùn)動(dòng),上模壓卸料板彈簧開始?jí)嚎s。卸料板受彈簧壓力壓緊條料,在這一過程中,沖裁和拉深凸模開始工作。6)在沖床經(jīng)過下死點(diǎn)后,沖床滑塊帶動(dòng)上模開始回升,凸模退回一段距離后此時(shí)在模具下面的推件板推工件出凹模，上部的活動(dòng)凹模推工件出凸模。9)沖床滑塊帶動(dòng)上模繼續(xù)上行,回到開模狀態(tài)的最高點(diǎn)完成一次沖壓過程。10)板料送進(jìn)一個(gè)步距，準(zhǔn)備下一個(gè)工作循環(huán)。 結(jié) 論本次畢業(yè)設(shè)計(jì)歷時(shí)三個(gè)月，設(shè)計(jì)過程中本人收集了大量有關(guān)沖壓模具設(shè)計(jì)的資料與實(shí)例，吸收了許多資料的精華部分，因此，本文內(nèi)容詳細(xì)而豐富。同時(shí)，本人對(duì)端蓋復(fù)合模的各個(gè)結(jié)構(gòu)做了充分地研究與論證，并多次改進(jìn)了設(shè)計(jì)結(jié)構(gòu)。在這次設(shè)計(jì)中，我遇到的難點(diǎn)主要有坯料的計(jì)算和工藝順序的安排，通過老師的指導(dǎo)幫助，更改了一些模具結(jié)構(gòu)，能夠完成預(yù)期目標(biāo)。通過這次設(shè)計(jì)，我學(xué)到了許多的東西。首先對(duì)于AUTOCAD2007和Pro/E的應(yīng)用更加熟練；其次，通過模具設(shè)計(jì)使我對(duì)于沖模工藝設(shè)計(jì)的流程很熟悉。這次設(shè)計(jì)是對(duì)以前所學(xué)的專業(yè)知識(shí)的一次綜合性的實(shí)踐。涉及到機(jī)械制圖、機(jī)械設(shè)計(jì)、模具設(shè)計(jì)、互換性以及CAD/CAM各個(gè)方面的內(nèi)容，使我受益非淺。同時(shí)能夠使我在以后的工作中更能將所學(xué)的知識(shí)付諸實(shí)踐，總結(jié)經(jīng)驗(yàn)，不斷進(jìn)步。致 謝本畢業(yè)設(shè)計(jì)，我的第一副沖壓設(shè)計(jì)模具，選題適合，結(jié)構(gòu)比較復(fù)雜。在規(guī)定的時(shí)間內(nèi)完成從模具裝配結(jié)構(gòu)及零件的設(shè)計(jì)。除了自己的努力外,更多的是要感謝指導(dǎo)老師在我設(shè)計(jì)課題從方案確定到具體實(shí)現(xiàn)結(jié)構(gòu)上的熱情指導(dǎo)。老師不斷的督促，使我不敢有絲毫懈怠，加緊完成了我的畢業(yè)設(shè)計(jì)。老師的指導(dǎo)以及同學(xué)的幫助讓我修正了設(shè)計(jì)中一個(gè)又一個(gè)的錯(cuò)誤,更重要的是我從中學(xué)到了很多東西,這些在原來學(xué)過的教材中是無法找到的,這些也是我以后工作中很寶貴的財(cái)富。在此，深深的表示感謝！參考文獻(xiàn)1中國機(jī)械工程學(xué)會(huì)鍛壓學(xué)會(huì)鍛壓手冊(cè)沖壓版第2版.機(jī)械工業(yè)出版社，2005 2翁其金，徐新成.沖壓工藝及模具設(shè)計(jì).機(jī)械工業(yè)出版社,20063二代龍震工作室.沖壓模具設(shè)計(jì)基礎(chǔ).電子工業(yè)出版社，20064王同海,孫勝，肖白白.實(shí)用沖壓設(shè)計(jì)技術(shù).機(jī)械工業(yè)出版,19965沈興東,韓森和.沖壓工藝與模具設(shè)計(jì).山東科學(xué)技術(shù)出版社，20056翁其金.冷沖壓技術(shù).機(jī)械工業(yè)出版社，20007鐘毓斌.沖壓工藝與模具設(shè)計(jì).機(jī)械工業(yè)出版社,20048中華人民共和國航天工業(yè)部部標(biāo)準(zhǔn).冷沖模.中華人民共和國航天工業(yè)部，19849模具實(shí)用技術(shù)叢書編委會(huì).沖模設(shè)計(jì)應(yīng)用實(shí)例.機(jī)械工業(yè)出版社,200410姜奎華.沖壓工藝與模具技術(shù).機(jī)械工業(yè)出版社,200511鄭家賢.沖壓工藝與模具設(shè)計(jì)實(shí)用技術(shù).機(jī)械工業(yè)出版社,200512M. Karima, Blank development and tooling design drawn parts using a modified slip line field based approach, ASME Trans. J. Eng. Ind. 111 (1989), pp. 345.13S Yossifon et al. On the Acceptable Blank-Holder Force Range in the Deep-Drawing Process. J. J. Mater, Process Technology, 1992,(33)23 第 26 頁 共 27 頁e pos 模具工業(yè)現(xiàn)狀Process simulation in stamping recent applications for product and process designAbstractProcess 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 Intl, 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 design1. IntroductionThe 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 ones investment in presses, equipment, and tooling used in sheet forming, one may increase ones 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 Intl). 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 applicationsThe objective of this investigation was to validate FAST_FORM3D, to determine FAST_FORM3Ds 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 5in. deep 12in. by 15in. rectangular pan with a 1in. flange as shown in Fig. 3. Table 1 lists the process conditions used. Romanovskis 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) Romanovskis 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 1in. flange in the side region, while the Romanovski and FAST_FORM3D methods achieved the 1in. 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_FORM3Ds 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 applicationsIn 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 excavators 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 50ton) 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 10ton, wrinkling occurred in the experimental parts as shown in Fig. 11. At 30ton, the wrinkling was eliminated as shown in Fig. 12. These experimental observations were predicted with Pam-stamp simulations as shown in Fig. 13. The 30ton 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 10mm. A slight neck was observed in the 30ton panel as shown in Fig. 13. At 50ton, an obvious fracture occurred in the panel.Fig. 11. Wrinkling in laboratory cabin inner panel, BHF=10ton.Fig. 12. Deformation stages of the laboratory cabin inner and necking, BHF=30ton. (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=10ton; (b) predicted geometry, BHF=30ton.Fig. 14. Comparison of predicted and measured material draw-in for lab cabin inner, BHF=30ton.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 50ton. 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=10ton (panel wrinkled); (b) measured strain, BHF=30ton (panel necked); (c) measured strain, BHF =50ton (panel fractured).Fig. 16. FEM strain predictions for the laboratory cabin inner. (a) Predicted strain, BHF=10ton; (b) predicted strain, BHF=30ton; (c) predicted strain, BHF=50ton.Fig. 17. Predicted effect of friction for the laboratory cabin inner, BHF=30ton. (a) Predicted strain, =0.06; (b) predicted strain, =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 applicationsThe 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 1Hz. It is known from previous experiments of other researchers that proper frequencies range from 5 to 25Hz 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 =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