軸承蓋沖壓工藝與模具設(shè)計(jì)
軸承蓋沖壓工藝與模具設(shè)計(jì),軸承蓋沖壓工藝與模具設(shè)計(jì),軸承,沖壓,工藝,模具設(shè)計(jì)
中期檢查表學(xué)生姓名 學(xué) 號(hào)指導(dǎo)教師選題情況課題名稱難易程度偏難適中偏易工作量較大合理較小符合規(guī)范化的要求任務(wù)書有無(wú)開(kāi)題報(bào)告有無(wú)外文翻譯質(zhì)量?jī)?yōu)良中差學(xué)習(xí)態(tài)度、出勤情況好一般差工作進(jìn)度快按計(jì)劃進(jìn)行慢中期工作匯報(bào)及解答問(wèn)題情況優(yōu)良中差中期成績(jī)?cè)u(píng)定：所在專業(yè)意見(jiàn)： 負(fù)責(zé)人： 年 月 日設(shè)計(jì)任務(wù)書系 部： 專 業(yè)： 學(xué)生姓名: 學(xué) 號(hào): 設(shè)計(jì)題目： 軸承蓋沖壓工藝與模具設(shè)計(jì) 起 迄 日 期: 指 導(dǎo) 教 師: 2013年 11 月 2 日 畢 業(yè) 設(shè) 計(jì) 任 務(wù) 書1本畢業(yè)設(shè)計(jì)課題來(lái)源及應(yīng)達(dá)到的目的：該課題來(lái)源于實(shí)際生產(chǎn)，通過(guò)對(duì)端蓋的具體分析與計(jì)算，要求合理地進(jìn)行沖裁與拉深工藝與模具設(shè)計(jì)，使學(xué)生對(duì)沖壓工藝生產(chǎn)更為熟悉；通過(guò)畢業(yè)設(shè)計(jì)，要求應(yīng)能熟練使用相關(guān)設(shè)計(jì)手冊(cè)，獨(dú)立完成一套模具的設(shè)計(jì)及模具工作零件加工工藝的編制；并且能夠運(yùn)用模具設(shè)計(jì)軟件完成模具裝配圖及零件圖的繪制。2本畢業(yè)設(shè)計(jì)課題任務(wù)的內(nèi)容和要求（包括原始數(shù)據(jù)、技術(shù)要求、工作要求等）：（1）了解目前國(guó)內(nèi)外冷沖壓模具的發(fā)展現(xiàn)狀；（2）端蓋的結(jié)構(gòu)工藝分析并確定其工藝方案；（3）端蓋沖壓成形工藝與模具設(shè)計(jì)計(jì)算，并編寫設(shè)計(jì)說(shuō)明書一份；（4）繪制模具總裝圖一張，繪制重要零件的零件圖，并手繪一張零件圖；。 材料：08 F 厚度：1.0mm 生產(chǎn)批量：中批量生產(chǎn) 所在專業(yè)審查意見(jiàn)：負(fù)責(zé)人： 年 月 日系部意見(jiàn)：系領(lǐng)導(dǎo)： 年 月 日 機(jī) 械 加 工 工 藝 過(guò) 程 卡 模具號(hào)零件號(hào)零 件 名 稱0116下模座板工序號(hào) 工 序 名 稱設(shè) 備夾 具 刀 具量 具工 時(shí)名 稱型 號(hào)名 稱規(guī) 格名 稱規(guī) 格名 稱規(guī) 格01 備料（鑄造成型），時(shí)效處理02刨平面，刨上、下平面，保證尺寸45.8牛頭刨床游標(biāo)卡尺03銑床加工，按線銑前部平面。銑臺(tái)肩至尺寸，銑側(cè)面作為基準(zhǔn)面銑床游標(biāo)卡尺04鉗工劃線，劃導(dǎo)柱孔和通孔線，銷釘孔線，頂桿孔線游標(biāo)卡尺，高度尺05鏜導(dǎo)柱孔至尺寸25鏜床游標(biāo)卡尺06鉆床加工立式鉆床游標(biāo)卡尺07鉸銷釘孔，和上模重疊，一起鉸孔至尺寸鉸刀08磨平面，磨上下平面，保證尺寸45平面磨床游標(biāo)卡尺09檢驗(yàn)游標(biāo)卡尺 編制 校對(duì) 審核 批準(zhǔn) 機(jī) 械 加 工 工 藝 過(guò) 程 卡 模具號(hào)零件號(hào)零 件 名 稱0105墊板工序號(hào) 工 序 名 稱設(shè) 備夾 具 刀 具量 具工 時(shí)名 稱型 號(hào)名 稱規(guī) 格名 稱規(guī) 格名 稱規(guī) 格01 備料02銑床加工，按線銑上下平面。銑六面至尺寸銑床游標(biāo)卡尺03鉗工劃線，劃通孔。游標(biāo)卡尺，高度尺04鉆床加工，鉆通孔至12、10、立式鉆床游標(biāo)卡尺05磨平面，磨上下平面，保證平行度0.05，并至尺寸。平面磨床游標(biāo)卡尺06檢驗(yàn)游標(biāo)卡尺 編制 校對(duì) 審核 批準(zhǔn) 設(shè)計(jì)評(píng)語(yǔ)學(xué)生姓名： 班級(jí): 學(xué)號(hào)： 題 目： 軸承蓋沖壓工藝及模具設(shè)計(jì) 綜合成績(jī)： 指導(dǎo)者評(píng)語(yǔ)：1）該同學(xué)工作態(tài)度較認(rèn)真，能較好的完成畢業(yè)設(shè)計(jì)任務(wù)；2）該同學(xué)查閱了國(guó)內(nèi)有關(guān)沖壓模具設(shè)計(jì)與制造方面的大量資料，制訂出了較合理的沖壓成形工藝及模具結(jié)構(gòu)，設(shè)計(jì)中不存在創(chuàng)新；3）該同學(xué)設(shè)計(jì)說(shuō)明書內(nèi)容較完整，計(jì)算較正確，格式較規(guī)范；4）該同學(xué)裝配圖、零件圖設(shè)計(jì)較合理，圖紙質(zhì)量較高；5）建議該同學(xué)成績(jī)?cè)u(píng)定：良好；6）可以提交答辯。 指導(dǎo)者(簽字)： 年 月 日畢業(yè)設(shè)計(jì)評(píng)語(yǔ)評(píng)閱者評(píng)語(yǔ)： 評(píng)閱者(簽字)： 年 月 日答辯委員會(huì)（小組）評(píng)語(yǔ)： 答辯委員會(huì)（小組）負(fù)責(zé)人(簽字)： 年 月 日?？茖W(xué)校畢業(yè)設(shè)計(jì)說(shuō)明書畢業(yè)設(shè)計(jì)(論文)題目：軸承蓋沖壓工藝及模具設(shè)計(jì)系 部 專 業(yè) 班 級(jí) 學(xué)生姓名 學(xué) 號(hào) 指導(dǎo)教師 2014年 4月 16 日軸承蓋的沖壓工藝與模具設(shè)計(jì) 摘 要：我所學(xué)習(xí)的專業(yè)是模具設(shè)計(jì)與制造專業(yè)，這次的畢業(yè)設(shè)計(jì)任務(wù)是軸承蓋模具設(shè)計(jì)。該設(shè)計(jì)結(jié)合大學(xué)三年來(lái)所學(xué)習(xí)的專業(yè)知識(shí)和CAD軟件所設(shè)計(jì)出的一套模具。這套模具結(jié)合了制造廠家和生產(chǎn)廠家的實(shí)際情況綜合需求。本文首先簡(jiǎn)要的概述了模具設(shè)計(jì)在社會(huì)領(lǐng)域中的作用及其以后的發(fā)展方向，點(diǎn)明模具設(shè)計(jì)的重要意義。然后依據(jù)工件圖進(jìn)行工藝性分析，進(jìn)而確定了設(shè)計(jì)方案，計(jì)算出模具工作部分的尺寸，設(shè)計(jì)出工作零部件；然后依據(jù)設(shè)計(jì)要求選擇出各個(gè)標(biāo)準(zhǔn)零部件，然后設(shè)計(jì)出模具的總裝配圖。在設(shè)計(jì)中，最重要的就是設(shè)計(jì)方案的確定、坯料的計(jì)算和工作零部件的設(shè)計(jì)，這是設(shè)計(jì)的關(guān)鍵，這些設(shè)計(jì)的正確與否直接關(guān)系到成本的高低和設(shè)計(jì)模具能否正常工作；在設(shè)計(jì)的最后，總結(jié)了自己的心得和體會(huì)，并對(duì)我的指導(dǎo)老師表示感謝。通過(guò)次畢業(yè)設(shè)計(jì)使我不僅掌握了模具設(shè)計(jì)的一般流程，更學(xué)習(xí)到了好多課本上沒(méi)有學(xué)習(xí)到的知識(shí)，使我受益非淺。關(guān)鍵詞：模具設(shè)計(jì),壓力機(jī),工藝性分析,模具結(jié)構(gòu)BEARING COVER OF THE STAMPINGPROCESS AND DIE DESIGNABSTRACT : The speciality of study of our institute is the mold design and speciality of making, the graduation project task this time is lining with a tube of mold design. Its time to design and combine the professional knowledge of study and a set of moulds that CAD software designed over the past three years of university. This set of moulds have accorded with the actual conditions integration requirement of manufacturer and manufacturer . This text the brief role in social field of mould of summary and developing direction afterwards at first, point out in the important meaning of mold design. Then carry on the craft to analyse according to the work piece picture , and then has confirmed the design plan , calculate out mould work some size , design the job spare part; Then choose each standard spare part according to the designing requirement , then design the total installation diagram of the mould . In the design, the most important one is sureness , calculation of the blank and design of the job spare part of the design plan , this is the key to designing, whether these ones that are designed involve directly or not correctly whether the level of the cost and design mould could work normally; At the end that is designed , have summarized ones own gains and experience , and express thanks for my counselor. Make me not merely grasp the general procedure of plastic mold design through graduation project once, study to the knowledge not learning to get on many textbooks even more, benefit me a great deal. KEY WORDS: mold design ,machine, craft analysis ,mould structure 目 錄1 前 言11.1本課題研究的意義11.2國(guó)內(nèi)模具的現(xiàn)狀和發(fā)展趨勢(shì)21.2.1國(guó)內(nèi)模具的現(xiàn)狀21.2.2國(guó)內(nèi)模具的發(fā)展趨勢(shì)31.3國(guó)外模具的現(xiàn)狀和發(fā)展趨勢(shì)41.4拉深模具設(shè)計(jì)的設(shè)計(jì)思路52 工藝分析及計(jì)算62.1工藝分析及工藝方案確定62.2工藝計(jì)算82.2.1毛坯尺寸計(jì)算82.2.2成形次數(shù)的確定92.2.3沖壓工序壓力計(jì)算102.2.4工作部分尺寸計(jì)算102.2.5 壓力中心的計(jì)算122.2.6沖裁間隙的計(jì)算123 模具的分析153.1 模具的總體設(shè)計(jì)153.1.1模具類型的選擇153.1.2定位方式的選擇153.1.3卸料 出件方式的選擇153.1.4導(dǎo)向方式的選擇153 .2 模具工作部分尺寸計(jì)算153.2.1工作零件的結(jié)構(gòu)設(shè)計(jì)154 模具的裝配及加工194.1 模具總裝圖194.2沖壓設(shè)備的選用224.3模具的裝配22設(shè)計(jì)總結(jié)24致 謝25參考文獻(xiàn)26 軸承蓋沖壓成形工藝及模具設(shè)計(jì)1 前 言1.1本課題研究的意義 沖壓加工是現(xiàn)代機(jī)械制造業(yè)中先進(jìn)高效的加工方法之一。沖壓加工的應(yīng)用十分廣泛，不僅可以加工金屬材料，而且可以加工非金屬材料。在現(xiàn)代制造業(yè)，比如汽車、拖拉機(jī)、農(nóng)業(yè)機(jī)械、電機(jī)、電器、儀表、化工容器、玩具以及日常生活用品的生產(chǎn)方面，都占有十分重要的地位。當(dāng)然，沖壓加工在我國(guó)也存在著一些問(wèn)題和不足。如機(jī)械化、自動(dòng)化程度低、生產(chǎn)集中度低、沖壓板材自給率不足、品種規(guī)格不配套、科技成果轉(zhuǎn)化慢、先進(jìn)工藝推廣慢、專業(yè)人才缺乏、大、精模具依賴進(jìn)口等，因此，我們將還有很長(zhǎng)的路要走。課題來(lái)源于生產(chǎn)實(shí)際，探討沖壓加工中較常見(jiàn)零件的工藝方法和結(jié)構(gòu)設(shè)計(jì)。課題涉及知識(shí)面較廣，且設(shè)計(jì)要求較高，對(duì)學(xué)生的設(shè)計(jì)能力，特別是思考能力是一個(gè)很好的鍛煉。課題研究?jī)?nèi)容包括機(jī)械工程學(xué)科的力學(xué)，沖壓工藝與模具設(shè)計(jì)，材料學(xué)，機(jī)械原理，機(jī)械設(shè)計(jì)，公差與互換性，機(jī)械制造工藝等知識(shí)，特別鍛煉學(xué)生規(guī)范性設(shè)計(jì)的能力。使學(xué)生能得到全面的鍛煉。課題要求學(xué)生具備較強(qiáng)的機(jī)構(gòu)設(shè)計(jì)能力和創(chuàng)新能力，對(duì)學(xué)生是一個(gè)挑戰(zhàn)。課題為典型的機(jī)械設(shè)計(jì)類課題，涉及機(jī)械知識(shí)全面，與工程機(jī)械專業(yè)方向結(jié)合緊密。此次課程設(shè)計(jì)主要目的是為了培養(yǎng)學(xué)生的綜合運(yùn)用所學(xué)知識(shí)的能力以及團(tuán)隊(duì)合作的能力。需要學(xué)生把所學(xué)的知識(shí)重新溫習(xí)一遍，并且能夠靈活運(yùn)用，同時(shí)要求學(xué)生要學(xué)會(huì)主動(dòng)積極的去查閱手冊(cè)，來(lái)了解沖壓模設(shè)計(jì)所學(xué)要的各項(xiàng)數(shù)據(jù)。最終通過(guò)一組成員的共同努力來(lái)設(shè)計(jì)出符合實(shí)際生產(chǎn)要求的沖壓模具。251.2國(guó)內(nèi)模具的現(xiàn)狀和發(fā)展趨勢(shì)1.2.1國(guó)內(nèi)模具的現(xiàn)狀我國(guó)沖壓模具近年來(lái)發(fā)展很快，據(jù)不完全統(tǒng)計(jì)，2003年我國(guó)模具生產(chǎn)廠點(diǎn)約有2萬(wàn)多家，從業(yè)人員約50多萬(wàn)人，2004年模具行業(yè)的發(fā)展保持良好勢(shì)頭，模具企業(yè)總體上訂單充足，任務(wù)飽滿，2004年模具產(chǎn)值530億元。進(jìn)口模具18.13億美元，出口模具4.91億美元，分別比2003年增長(zhǎng)18%、32.4%和45.9%。進(jìn)出口之比2004年為3.69:1，進(jìn)出口相抵后的進(jìn)凈口達(dá)13.2億美元，為凈進(jìn)口量較大的國(guó)家在2萬(wàn)多家生產(chǎn)廠點(diǎn)中，有一半以上是自產(chǎn)自用的。在模具企業(yè)中，產(chǎn)值過(guò)億元的模具企業(yè)只有20多家，中型企業(yè)幾十家，其余都是小型企業(yè)。近年來(lái)，模具行業(yè)結(jié)構(gòu)調(diào)整和體制改革步伐加快，主要表現(xiàn)為：大型、精密、復(fù)雜、長(zhǎng)壽命中高檔模具及模具標(biāo)準(zhǔn)件發(fā)展速度快于一般模具產(chǎn)品；專業(yè)模具廠數(shù)量增加，能力提高較快；三資及私營(yíng)企業(yè)發(fā)展迅速；國(guó)企股份制改造步伐加快等。雖然說(shuō)我國(guó)模具業(yè)發(fā)展迅速，但遠(yuǎn)遠(yuǎn)不能適應(yīng)國(guó)民經(jīng)濟(jì)發(fā)展的需要。低檔模具過(guò)剩，高檔模具供不應(yīng)求，甚至有的依賴進(jìn)口，因此，模具企業(yè)必須找準(zhǔn)自己的弱點(diǎn)，盡快縮短與國(guó)外的差距。(1)體制不順，基礎(chǔ)薄弱“三資”企業(yè)雖然已經(jīng)對(duì)中國(guó)模具工業(yè)的發(fā)展起了積極的推動(dòng)作用，私營(yíng)企業(yè)近年來(lái)發(fā)展較快，國(guó)企改革也在進(jìn)行之中，但總體來(lái)看，體制和機(jī)制尚不適應(yīng)市場(chǎng)經(jīng)濟(jì)，再加上國(guó)內(nèi)模具工業(yè)基礎(chǔ)薄弱，因此，行業(yè)發(fā)展還不盡如人意，特別是總體水平和高新技術(shù)方面。 (2)人才嚴(yán)重不足，科研開(kāi)發(fā)及技術(shù)攻關(guān)方面投入太少模具行業(yè)是技術(shù)密集、資金密集的產(chǎn)業(yè)，隨著時(shí)代進(jìn)步和技術(shù)發(fā)展，能掌握和運(yùn)用新技術(shù)的人才異常短缺，高級(jí)模具鉗工及企業(yè)管理人才也非常緊缺。由于模具企業(yè)效益欠佳及對(duì)科研開(kāi)發(fā)和技術(shù)攻關(guān)不夠重視，因而總體來(lái)看模具行業(yè)在科研開(kāi)發(fā)和技術(shù)攻關(guān)方面投入太少，民營(yíng)企業(yè)貸款困難也影響許多企業(yè)的技術(shù)改造，致使科技進(jìn)步不大。 (3)工藝裝備水平低，且配套性不好，利用率低雖然國(guó)內(nèi)許多企業(yè)采用了先進(jìn)的加工設(shè)備，但總的來(lái)看裝備水平仍比國(guó)外企業(yè)落后許多，特別是設(shè)備數(shù)控化率和CAD/CAM應(yīng)用覆蓋率要比國(guó)外企業(yè)低得多。由于體制和資金等原因，引進(jìn)設(shè)備不配套，設(shè)備與附配件不配套現(xiàn)象十分普遍，設(shè)備利用率低的問(wèn)題長(zhǎng)期得不到較好解決。裝備水平低，帶來(lái)中國(guó)模具企業(yè)鉗工比例過(guò)高等問(wèn)題。(4)專業(yè)化、標(biāo)準(zhǔn)化、商品化的程度低、協(xié)作差 由于長(zhǎng)期以來(lái)受“大而全”“小而全”影響，許多模具企業(yè)觀念落后，模具企業(yè)專業(yè)化生產(chǎn)水平低，專業(yè)化分工不細(xì)，商品化程度也低。目前國(guó)內(nèi)每年生產(chǎn)的模具，商品模具只占45%左右，其余為自產(chǎn)自用。模具企業(yè)之間協(xié)作不好，難以完成較大規(guī)模的模具成套任務(wù)，與國(guó)際水平相比要落后許多。模具標(biāo)準(zhǔn)化水平低，標(biāo)準(zhǔn)件使用覆蓋率低也對(duì)模具質(zhì)量、成本有較大影響，對(duì)模具制造周期影響尤甚。 (5)模具材料及模具相關(guān)技術(shù)落后模具材料性能、質(zhì)量和品種往往會(huì)影響模具質(zhì)量、壽命及成本，國(guó)產(chǎn)模具鋼與國(guó)外進(jìn)口鋼相比，無(wú)論是質(zhì)量還是品種規(guī)格，都有較大差距。塑料、板材、設(shè)備等性能差，也直接影響模具水平的提高。1.2.2國(guó)內(nèi)模具的發(fā)展趨勢(shì)巨大的市場(chǎng)需求將推動(dòng)中國(guó)模具的工業(yè)調(diào)整發(fā)展。雖然我國(guó)的模具工業(yè)和技術(shù)在過(guò)去的十多年得到了快速發(fā)展，但與國(guó)外工業(yè)發(fā)達(dá)國(guó)家相比仍存在較大差距，尚不能完全滿足國(guó)民經(jīng)濟(jì)高速發(fā)展的需求。未來(lái)的十年，中國(guó)模具工業(yè)和技術(shù)的主要發(fā)展方向包括以下幾方面:(1)模具日趨大型化；(2)在模具設(shè)計(jì)制造中廣泛應(yīng)用CAD/CAE/CAM技術(shù)；(3)模具掃描及數(shù)字化系統(tǒng)；(4)在塑料模具中推廣應(yīng)用熱流道技術(shù)、氣輔注射成型和高壓注射成型技術(shù)；(5)提高模具標(biāo)準(zhǔn)化水平和模具標(biāo)準(zhǔn)件的使用率；(6)發(fā)展優(yōu)質(zhì)模具材料和先進(jìn)的表面處理技術(shù)；(7)模具的精度將越來(lái)越高；(8)模具研磨拋光將自動(dòng)化、智能化；(9)研究和應(yīng)用模具的高速測(cè)量技術(shù)與逆向工程；(10)開(kāi)發(fā)新的成形工藝和模具。1.3國(guó)外模具的現(xiàn)狀和發(fā)展趨勢(shì)模具是工業(yè)生產(chǎn)關(guān)鍵的工藝裝備，在電子、建材、汽車、電機(jī)、電器、儀器儀表、家電和通訊器材等產(chǎn)品中，6080的零部件都要依靠模具成型。用模具生產(chǎn)制作表現(xiàn)出的高效率、低成本、高精度、高一致性和清潔環(huán)保的特性，是其他加工制造方法所無(wú)法替代的。模具生產(chǎn)技術(shù)水平的高低，已成為衡量一個(gè)國(guó)家制造業(yè)水平高低的重要標(biāo)志，并在很大程度上決定著產(chǎn)品的質(zhì)量、效益和新產(chǎn)品的開(kāi)發(fā)能力。近幾年，全球模具市場(chǎng)呈現(xiàn)供不應(yīng)求的局面，世界模具市場(chǎng)年交易總額為600650億美元左右。美國(guó)、日本、法國(guó)、瑞士等國(guó)家年出口模具量約占本國(guó)模具年總產(chǎn)值的三分之一。國(guó)外模具總量中,大型、精密、復(fù)雜、長(zhǎng)壽命模具的比例占到50%以上；國(guó)外模具企業(yè)的組織形式是大而專、大而精。2004年中國(guó)模協(xié)在德國(guó)訪問(wèn)時(shí)，從德國(guó)工、模具行業(yè)組織-德國(guó)機(jī)械制造商聯(lián)合會(huì)（VDMA）工模具協(xié)會(huì)了解到，德國(guó)有模具企業(yè)約5000家。2003年德國(guó)模具產(chǎn)值達(dá)48億歐元。其中（VDMA）會(huì)員模具企業(yè)有90家，這90家骨干模具企業(yè)的產(chǎn)值就占德國(guó)模具產(chǎn)值的90%，可見(jiàn)其規(guī)模效益。 隨著時(shí)代的進(jìn)步和技術(shù)的發(fā)展，國(guó)外的一些掌握和能運(yùn)用新技術(shù)的人才如模具結(jié)構(gòu)設(shè)計(jì)、模具工藝設(shè)計(jì)、高級(jí)鉗工及企業(yè)管理人才，他們的技術(shù)水平比較高故人均產(chǎn)值也較高我國(guó)每個(gè)職工平均每年創(chuàng)造模具產(chǎn)值約合1萬(wàn)美元左右，而國(guó)外模具工業(yè)發(fā)達(dá)國(guó)家大多1520萬(wàn)美元，有的達(dá)到 2530萬(wàn)美元。國(guó)外先進(jìn)國(guó)家模具標(biāo)準(zhǔn)件使用覆蓋率達(dá)70%以上，而我國(guó)才達(dá)到45。1.4拉深模具設(shè)計(jì)的設(shè)計(jì)思路拉深是沖壓基本工序之一，它是利用拉深模在壓力機(jī)作用下，將平板坯料或空心工序件制成開(kāi)口空心零件的加工方法。它不僅可以加工旋轉(zhuǎn)體零件，還可以加工盒形零件及其他形狀復(fù)雜的薄壁零件，但是，加工出來(lái)的制件的精度都很底。一般情況下，拉深件的尺寸精度應(yīng)在IT13級(jí)以下，不宜高于IT11級(jí)。有凸緣圓筒形件是最典型的拉深件，其工作過(guò)程很簡(jiǎn)單就一個(gè)拉深，根據(jù)計(jì)算確定它不能一次拉深成功.因此，需要多次拉深。為了保證制件的順利加工和順利取件，模具必須有足夠高度。要改變模具的高度，只有從改變導(dǎo)柱和導(dǎo)套的高度,改變導(dǎo)柱和導(dǎo)套的高度的同時(shí),還要注意保證導(dǎo)柱和導(dǎo)套的強(qiáng)度. 導(dǎo)柱和導(dǎo)套的高度可根據(jù)拉深凸模與拉深凹模工作配合長(zhǎng)度決定設(shè)計(jì)時(shí)可能高度出現(xiàn)誤差，應(yīng)當(dāng)邊試沖邊修改高度。2 工藝分析及計(jì)算2.1工藝分析及工藝方案確定冷沖壓工藝是機(jī)械制造業(yè)中一種較先進(jìn)的加工方法，與切削加工相比，具有材料利用率高，制品力學(xué)性能好，互換性強(qiáng)，生產(chǎn)效率高等優(yōu)點(diǎn)。在經(jīng)濟(jì)技術(shù)方面都有很大的優(yōu)越性，把鑄件改為沖壓件，目的是為了提高生產(chǎn)率，降低成本，增加經(jīng)濟(jì)效益，但是否可行，需要具備如下條件：制品改制后須不降低原使用性能要求。制品須具有相當(dāng)?shù)纳a(chǎn)批量。改制后的制件應(yīng)具有良好的沖壓工藝性。分析其沖壓性，由工件圖所示主要工藝難點(diǎn)在于四個(gè)凸臺(tái)的成形，其相對(duì)高度較大，凸臺(tái)之間距離又相對(duì)較小，因此在成形過(guò)程中，材料變形復(fù)雜，尤其在凸臺(tái)內(nèi)側(cè)及兩凸臺(tái)之間園弧部分，材料補(bǔ)充困難，僅靠變薄拉深難以達(dá)到要求，且易出現(xiàn)拉裂。經(jīng)充分考慮成形條件和沖壓工藝難點(diǎn)分析，提出改進(jìn)設(shè)計(jì)后沖壓工藝要點(diǎn)： 采用預(yù)沖中心孔，以改善四個(gè)凸臺(tái)內(nèi)側(cè)及凸臺(tái)之間材料流動(dòng)。 將毛坯下成方形，以便四角從外側(cè)補(bǔ)充四個(gè)凸臺(tái)用料。 采用先將四凸臺(tái)拉深成一定高度時(shí)再落制件外圓料的方法，使得在拉深過(guò)程中材料易于得到補(bǔ)充且外圓相對(duì)準(zhǔn)確。 該工件屬于圓筒形拉深，形狀略有點(diǎn)復(fù)雜，所有的尺寸均為自由公差，對(duì)工件厚度要求不太大，該工件軸承蓋做為另一零件的蓋，工件的高度.，可在拉深后采用修邊達(dá)到要求。 該工件包括落料拉深 沖孔 翻邊 四個(gè)基本工序，可以有以下三種方案： 一. 先拉深 后落料 翻邊 再?zèng)_孔。采用單工序模生產(chǎn)。二. 先拉深，采用單工序模具，后采用沖孔落料復(fù)合沖壓。三. 拉深級(jí)進(jìn)沖壓。采用級(jí)進(jìn)模生產(chǎn)。方案一模具結(jié)構(gòu)簡(jiǎn)單，但需要四道工序四幅模具，生產(chǎn)效率低，難以達(dá)到該工件中批量生產(chǎn)的要求。方案二只需兩幅模具，生產(chǎn)效率較高，盡管模具結(jié)構(gòu)較方案一復(fù)雜，但由于零件的幾何形狀對(duì)稱，模具制造并不困難。方案三只需一幅模具，生產(chǎn)效率高，但模具結(jié)構(gòu)比較復(fù)雜，送料操作不方便，加之工件尺寸偏大。通過(guò)上述三種方案的分析比較，方案二較為宜。零件圖如下1所示圖1材料：08F 厚度1mm生產(chǎn)批量：中批量生產(chǎn)（每月2000-4000件）2.2工藝計(jì)算2.2.1毛坯尺寸計(jì)算根據(jù)相似原則，求零件的毛坯直徑，先計(jì)算出零件總面積，然后根據(jù)表面積相等的原則，計(jì)算出直徑.沖裁面積=15686.4落料力 其中L沖裁周邊長(zhǎng)度 t材料厚度 b材料抗剪強(qiáng)度（查的材料抗剪強(qiáng)度取300Mpa） K系數(shù)（一般取1.3）因此=1.3443.871300=173109.3N拉深力 d其中 b材料的抗拉強(qiáng)度（取為320Mpa）t材料厚度K1修正系數(shù)（查表4.6取0.6）計(jì)算得F=65713.92N壓邊力其中D毛坯直徑 d拉深后工件直徑 r凹拉深凹模圓角半徑 p單位壓邊力（查遍4.8取P=2.3）計(jì)算得F壓=11363N沖壓工藝總力250186N料厚t/mmKxKtKd鋼0.10.10.50.50.252.56.56.50.0650.0750.0450.0550.040.050.030.040.020.030.10.0630.0550.0450.0250.140.080.060.050.03鋁、鋁合金純銅，黃銅0.0250.080.020.060.030.070.030.09表12.2.2成形次數(shù)的確定該工件底部有一臺(tái)階，按階梯形件的拉伸來(lái)計(jì)算，求出h/=7.5/17=0.441,根據(jù)毛坯相對(duì)厚度t/D=1/109=0.91,查表現(xiàn)h/小于表中數(shù)值，能一次拉伸成形，2.2.3沖壓工序壓力計(jì)算該模具擬采用正裝復(fù)合模，故采用固定卸料與推件，具體沖壓力計(jì)算如上述計(jì)算所示。根據(jù)沖壓力計(jì)算結(jié)果并結(jié)合工件高度，初選開(kāi)式雙柱可傾壓力機(jī)J23-20。2.2.4工作部分尺寸計(jì)算落料和拉伸的凸 凹模工作尺寸見(jiàn)下表所示，其中因該工件口部尺寸要求要與另一件配合，所以在設(shè)計(jì)時(shí)可將其尺寸做小些，即拉深凹模尺寸取mm mm;相應(yīng)拉深凸模取mm mm；工件尺寸10 R4 88。因?yàn)閷儆谶^(guò)渡尺寸，要求不高，為簡(jiǎn)單方便，實(shí)際生產(chǎn)中直接按工件尺寸拉深凸凹模該處尺寸。凸凹模雙面間隙（占料厚t%）材料厚度（t/mm)外形/t%內(nèi)形/t%dd=5td5t0.52.52112.52122.510.53210.541.70.750.561.70.50.5101.50.50.51510.50.5表2拉深凸凹模尺寸計(jì)算尺寸及分類凸凹模間雙面間隙尺寸偏差與磨損系數(shù)計(jì)算公式結(jié)果備注拉深50查表2得Z=2.5mm=0.74=17=0.43=落料141.36查表4得=0.14mm=0.10mm =0.5X=0.75=表32.2.5 壓力中心的計(jì)算由于該零件是一個(gè)圓形圖形，屬于對(duì)稱中心零件，所以該零件的壓力中心在圖形的幾何中心O處。2.2.6沖裁間隙的計(jì)算 設(shè)計(jì)模具時(shí)一定要選擇合理的間隙，以保證沖裁件的斷面質(zhì)量、尺寸精度滿足產(chǎn)品的要求，所需沖裁力小、模具壽命高，但分別從質(zhì)量，沖裁力、模具壽命等方面的要求確定的合理間隙并不是同一個(gè)數(shù)值，只是彼此接近。考慮到制造中的偏差及使用中的磨損、生產(chǎn)中通常只選擇一個(gè)適當(dāng)?shù)姆秶鳛楹侠黹g隙，只要間隙在這個(gè)范圍內(nèi)，就可以沖出良好的制件，這個(gè)范圍的最小值稱為最小合理間隙Cmin，最大值稱為最大合理間隙Cmax?？紤]到模具在使用過(guò)程中的磨損使間隙增大，故設(shè)計(jì)與制造新模具時(shí)要采用最小合理間隙值Cmin。沖裁間隙的大小對(duì)沖裁件的斷面質(zhì)量有極其重要的影響，此外，沖裁間隙還影響模具壽命、卸料力、推件力、沖裁力和沖裁件的尺寸精度。沖裁過(guò)程中，凸模與被沖的孔之間，凹模與落料件之間均有摩擦，間隙越小，模具作用的壓應(yīng)力越大，摩擦也越嚴(yán)重，而降低了模具的壽命。較大的間隙可使凸模側(cè)面及材料間的摩擦減小，并延緩間隙由于受到制造和裝配精度的限制，雖然提高了模具壽命而，但出現(xiàn)間隙不均勻。因此，沖裁間隙是沖裁工藝與模具設(shè)計(jì)中的一個(gè)非常重要的工藝參數(shù)。根據(jù)實(shí)用間隙表4 查得08F的最小雙面間隙Zmin=0.100mm，最大雙面間隙Zmax=0.140mm沖裁模初始用間隙Z(mm)材料厚度t/mm08、10、35、09Mn、Q23516Mn40、5065MnZminZmaxZminZmaxZminZmaxZminZmax小于0.5極小間隙0.50.60.70.80.91.01.21.51.752.02.12.52.753.03.54.04.55.56.06.58.00.0400.0480.0640.0720.0920.1000.1260.1320.2200.2460.2600.2600.4000.4600.5400.6100.7200.9401.0800.0600.0720.0920.1040.1260.1400.1800.2400.3200.3600.3800.5000.5600.6400.7400.8801.0001.2801.4400.0400.0480.0640.0720.0900.1000.1320.1700.2200.2600.2800.3800.4200.4800.5800.6800.6800.7800.8400.9401.2000.0600.0720.0920.1040.1260.1400.1800.2400.3200.3800.4000.5400.6000.6600.7800.9200.9601.1001.2001.3001.6800.0400.0480.0640.0720.0900.1000.1320.1700.2200.2600.2800.3800.4200.4800.5800.6800.7800.9801.1400.0600.0720.0920.1040.1260.1400.1800.2400.3200.3800.4000.5400.6000.6600.7800.9201.0401.3201.5000.0400.0480.0640.0640.0900.0900.0600.0720.0920.0920.1260.126注：取08號(hào)鋼沖裁皮革、石棉和紙板時(shí)，間隙的25%。表43 模具的分析3.1 模具的總體設(shè)計(jì) 3.1.1模具類型的選擇 由沖壓工藝分析可知，拉深采用單工序模具，落料沖孔部分采用復(fù)合模結(jié)構(gòu)。 3.1.2定位方式的選擇 對(duì)于該單工序拉深模具使用的是圓形坯料，所以拉深工序模具采用定位圈進(jìn)行定位，無(wú)須擋料銷。對(duì)于沖孔落料模具采用落料凹模上的凹槽進(jìn)行定位。3.1.3卸料 出件方式的選擇 模具采用固定卸料，剛性打料，并利用裝在壓力機(jī)工作臺(tái)下的標(biāo)準(zhǔn)緩沖器提供壓邊力。下方設(shè)兩個(gè)頂桿用于制件的頂出。3.1.4導(dǎo)向方式的選擇 為了提高模具壽命和工件質(zhì)量，方便安裝調(diào)整，該復(fù)合模采用中間導(dǎo)柱的導(dǎo)向方式。3 .2 模具工作部分尺寸計(jì)算 3.2.1工作零件的結(jié)構(gòu)設(shè)計(jì) 1.由于工件對(duì)稱，所以模具的工作零件采用整體結(jié)構(gòu)。對(duì)于單工序的拉深模，為保證先預(yù)沖中心孔，模具的端面比沖孔凸模端面低。所以拉深凸模其長(zhǎng)度L可按下式計(jì)算： L=20mm+20+35+7.5 =82.5mm沖孔凸模=82.5+3=85.5凸模固定板的厚度，=20mm凹模的厚度，=35mm裝配后，拉深凸模的端高于于沖孔凸模端面的高度，根據(jù)料厚大小，決定=3mm。 凸、凹模選用Gr12鋼，為了防止淬火變形，應(yīng)采用工作部分局部淬火。2.對(duì)于沖孔落料復(fù)合模具，為保證先落料在沖孔，落料凸模的端面比沖孔凸模端面低。所以拉深凸模其長(zhǎng)度L可按下式計(jì)算： L=20+20+35+7.5+3 =85.5mm凸模固定板的厚度，=20mm落料凹模的厚度，=35mm裝配后，落料凸模的端高于于沖孔凸模端面的高度，根據(jù)料厚大小，決定=3mm。 3.2.2其他零部件的設(shè)計(jì)與選用 彈性元件的設(shè)計(jì)卸料板在成形中一方面起壓邊作用，另一方面還可將成形后包在沖孔凸模上的工件卸下，其壓力有標(biāo)準(zhǔn)緩沖器提供。 模架及其他零部件的選用 模具選用中間導(dǎo)柱標(biāo)準(zhǔn)模架，可承受較大的沖壓力。為防止裝模時(shí)，上模誤轉(zhuǎn)裝配，將模架中兩對(duì)導(dǎo)柱與導(dǎo)套做成粗細(xì)不等：導(dǎo)柱d/mmL/mm分別為25170，28170；導(dǎo)套d/mmL/mmD/mm分別為259041，289045。 1.對(duì)于單工序拉深模具 上模座厚度取35mm，即=35mm 上模墊板厚度取10mm，即=10mm 卸料板取35mm，即=35mm 支承板厚度取30mm，即H支承=30mm 橡膠閉合高度為20mm 下模座厚度取45mm，即=45mm 模具閉合高度 =35+10+20+20+35+10+30+35+45+1 =231mm可見(jiàn)該模具閉合高度小于所選壓力機(jī)J2340的最大裝模高度，可以使用。2.對(duì)于沖孔落料復(fù)合模具導(dǎo)柱d/mmL/mm分別為25170，28170；導(dǎo)套d/mmL/mmD/mm分別為259041，289045。 上模座厚度取35mm，即=35mm 上模墊板厚度取10mm，即=10mm 卸料板取35mm，即=35mm 橡膠閉合高度為20mm 下模墊板厚度取10mm，即=10mm 下模座厚度取45mm，即=45mm 模具閉合高度=35+10+20+20+35+10+30+35+45+10+1 =241mm可見(jiàn)該模具閉合高度小于所選壓力機(jī)J2340的最大裝模高度，可以使用。兩幅模具各部分基本相同，便于生產(chǎn)加工。4 模具的裝配及加工4.1 模具總裝圖 對(duì)于單工序拉深模具模具的工作過(guò)程：將正方形坯料送入剛性卸料板下方正方形槽中，平放在凹模面上，并靠槽的一側(cè)，壓力機(jī)滑塊帶著上模下行，壓料板下端先壓住坯料，繼續(xù)下行；預(yù)沖空的凸模先接觸坯料完成預(yù)沖中心孔，當(dāng)沖孔結(jié)束后拉深凸模接觸坯料完成拉深工序。 對(duì)于沖孔落料復(fù)合模具的工作過(guò)程：將上道工序拉深成的半成品放入沖孔凹模的凹槽內(nèi)，起一定的定位作用，上模下行，卸料板首先接觸坯料，并起壓料作用，上模繼續(xù)下行，壓縮橡膠，卸料板壓緊坯料，落料凹模首先接觸坯料，完成落料工序，并與沖孔凹模共同完成翻邊工序，上模繼續(xù)下行，沖孔凸模接觸坯料完成沖孔工序，上模上行，卸料板完成卸料。 為達(dá)到零件尺寸要求，需在最后添加修邊工序。裝配圖如下圖2，圖3圖2拉深模圖3沖孔落料翻邊復(fù)合模4.2沖壓設(shè)備的選用 通過(guò)校核，兩幅模具的閉合高度均小于壓力機(jī)的最大閉合高度，因此選用開(kāi)式可傾壓力機(jī)J2340能滿足要求。該壓力機(jī)的的參數(shù)如下圖所示4.3模具的裝配兩套模具的裝配選凸 凹模為基準(zhǔn)件，先裝上模，再裝下模。裝配后應(yīng)保證間隙均勻，落料凹模刃口面應(yīng)高出拉深凸模工作面3mm，頂件塊上端面應(yīng)高出落料凹模刃口面0.5mm，以實(shí)現(xiàn)沖孔或者落料前先壓料，落料后再拉深。拉深模技術(shù)要求及加工特點(diǎn)：（1） 凸 凹模材質(zhì)應(yīng)具有高硬度 高耐磨性 高淬透性 熱處理變形小，形狀簡(jiǎn)單的凸 凹模一般用T10A CrWMn等，形狀復(fù)雜的凸 凹模一般用Cr12 Cr12MoV W18Cr4V等，熱處理后的硬度為5862HRC；（2） 凸 凹模精度主要根據(jù)拉深件精度決定，一般尺寸精度在IT6IT9，工作表面質(zhì)量一般要求很高，起凹模圓角和孔壁要求表面粗糙度Ra值為0.80.2微米，凸模工作表面粗糙度Ra值為1.60.8微米；（3） 由于回彈等因素在設(shè)計(jì)時(shí)難以準(zhǔn)確考慮，導(dǎo)致凸 凹模尺寸的計(jì)算值與實(shí)際要求值往往存在誤差。因此凸 凹模工作部分的形狀和尺寸設(shè)計(jì)應(yīng)合理，要留有試模后的修模余地；一般先設(shè)計(jì)和加工拉伸模后設(shè)計(jì)和加工沖裁模；（4） 凸凹模淬火有時(shí)可以在試模后進(jìn)行，以便試模后的修改；（5） 凸凹模圓角半徑和間隙的大小 分布符合設(shè)計(jì)要求 ；拉伸凸凹模的加工方法主要根據(jù)工作部分?jǐn)嗝嫘螤顩Q定。圓型一般車削加工，非圓形一般劃線后銑削加工，然后淬硬，最后研磨 拋光。 設(shè)計(jì)總結(jié) 在即將畢業(yè)之際，為了在我們現(xiàn)有的知識(shí)基礎(chǔ)上使我們的水平有進(jìn)一步的提高，根據(jù)教育部門的要求和學(xué)校的教學(xué)安排，我們進(jìn)行了這次畢業(yè)設(shè)計(jì)。首先于老師給我布置畢業(yè)設(shè)計(jì)的題目，對(duì)題目給于了認(rèn)真的分析和安排，使我們能夠做到胸有成竹，同時(shí)，我到圖書館借閱了許多質(zhì)料，有了充足的原始材料。其次，在具體設(shè)計(jì)過(guò)程中，我參照例子一步一步地進(jìn)行，對(duì)各步驟進(jìn)行了詳細(xì)和深入細(xì)致的計(jì)算。再次，在大量計(jì)算數(shù)據(jù)和原始數(shù)據(jù)基礎(chǔ)上，進(jìn)行了歸納總結(jié)，繪制出了幾張零件圖和一張裝配圖，并寫出了設(shè)計(jì)總結(jié)和感想體會(huì)。我想，通過(guò)我們這次畢業(yè)設(shè)計(jì)，我們對(duì)以前的知識(shí)有了一定的鞏固，同時(shí)還學(xué)到了新知識(shí)，自己的能力得到進(jìn)一步拔高，我會(huì)保存好我的底稿，將來(lái)時(shí)常翻閱。畢業(yè)設(shè)計(jì)是我們進(jìn)行完了三年的模具設(shè)計(jì)與制造專業(yè)課程后進(jìn)行的，它是對(duì)我們?nèi)陙?lái)所學(xué)課程的又一次深入、系統(tǒng)的綜合性的復(fù)習(xí)，也是一次理論聯(lián)系實(shí)踐的訓(xùn)練。它在我們的學(xué)習(xí)中占有重要的地位。 通過(guò)這次畢業(yè)設(shè)計(jì)使我在溫習(xí)學(xué)過(guò)的知識(shí)的同時(shí)又學(xué)習(xí)了許多新知識(shí)，一些原來(lái)一知半解的理論也有了進(jìn)一步的的認(rèn)識(shí)。特別是原來(lái)所學(xué)的一些專業(yè)基礎(chǔ)課：如機(jī)械制圖、模具材料、公差配合與技術(shù)測(cè)量、冷沖模具設(shè)計(jì)與制造等有了更深刻的理解，使我進(jìn)一步的了解了怎樣將這些知識(shí)運(yùn)用到實(shí)際的設(shè)計(jì)中。同時(shí)還使我更清楚了模具設(shè)計(jì)過(guò)程中要考慮的問(wèn)題，如怎樣使制造的模具既能滿足使用要求又不浪費(fèi)材料，保證工件的經(jīng)濟(jì)性，加工工藝的合理性。致 謝在學(xué)校中，我們主要學(xué)的是理論性的知識(shí)，而實(shí)踐性很欠缺，而畢業(yè)設(shè)計(jì)就相當(dāng)于實(shí)戰(zhàn)前的一次演練。通過(guò)畢業(yè)設(shè)計(jì)可是把我們以前學(xué)的專業(yè)知識(shí)系統(tǒng)的連貫起來(lái)，使我們?cè)跍亓?xí)舊知識(shí)的同時(shí)也可以學(xué)習(xí)到很多新的知識(shí)；這不但提高了我們解決問(wèn)題的能力，開(kāi)闊了我們的視野，在一定程度上彌補(bǔ)我們實(shí)踐經(jīng)驗(yàn)的不足，為以后的工作打下堅(jiān)實(shí)的基礎(chǔ)。通過(guò)對(duì)墊板制件冷沖模的設(shè)計(jì)，我對(duì)沖裁模有了更為深刻的認(rèn)識(shí)，特別是這種沖孔落料拉深復(fù)合模具的設(shè)計(jì)。在模具的設(shè)計(jì)過(guò)程中也遇到了一些難以處理的問(wèn)題，雖然設(shè)計(jì)中對(duì)它們做出了解決 ，但還是感覺(jué)這些方案中還是不能盡如人意，如壓力計(jì)算時(shí)的公式的選用、凸凹模間隙的計(jì)算、卸件機(jī)構(gòu)選用、工作零件距離的調(diào)整，都可以進(jìn)行進(jìn)一步的完善，使生產(chǎn)效率提高。歷經(jīng)近幾個(gè)月的畢業(yè)設(shè)計(jì)即將結(jié)束，敬請(qǐng)各位老師對(duì)我的設(shè)計(jì)過(guò)程作最后檢查。在這次畢業(yè)設(shè)計(jì)中通過(guò)參考、查閱各種有關(guān)模具方面的資料，請(qǐng)教各位老師有關(guān)模具方面的問(wèn)題，并且和同學(xué)的探討，模具設(shè)計(jì)在實(shí)際中可能遇到的具體問(wèn)題，使我在這短暫的時(shí)間里，對(duì)模具的認(rèn)識(shí)有了一個(gè)質(zhì)的飛躍。從陌生到開(kāi)始接觸，從了解到熟悉，這是每個(gè)人學(xué)習(xí)事物所必經(jīng)的一般過(guò)程，我對(duì)模具的認(rèn)識(shí)過(guò)程亦是如此。經(jīng)過(guò)近三個(gè)月的努力，我相信這次畢業(yè)設(shè)計(jì)一定能為三年的大學(xué)生涯劃上一個(gè)圓滿的句號(hào)，為將來(lái)的事業(yè)奠定堅(jiān)實(shí)的基礎(chǔ)。在這次設(shè)計(jì)過(guò)程中得到了老師以及許多同學(xué)的幫助，我受益匪淺。在此，再次感謝各位老師特別是我的指導(dǎo)老師于老師在這一段時(shí)間給予無(wú)私的幫助和指導(dǎo)，并向他們致于深深的敬意，對(duì)關(guān)心和指導(dǎo)過(guò)我各位老師表示衷心的感謝！參考文獻(xiàn)1 原紅玲 于智宏主編. 沖壓工藝與模具設(shè)計(jì) M. 機(jī)械工業(yè)出版社2010.8.1.2 翟德梅 段微峰主編. 模具制造技術(shù)M. 化學(xué)工業(yè)出版社 2005.5.3 閻亞林 主編. 沖壓與塑壓成型設(shè)備M.高等教育出版社 2010.4Int J Adv Manuf Technol (2002) 19:253259 2002 Springer-Verlag London Limited An Analysis of Draw-Wall Wrinkling in a Stamping Die Design F.-K. Chen and Y.-C. Liao Department of Mechanical Engineering, National Taiwan University, Taipei, Taiwan Wrinkling that occurs in the stamping of tapered square cups and stepped rectangular cups is investigated. A common characteristic of these two types of wrinkling is that the wrinkles are found at the draw wall that is relatively unsup- ported. In the stamping of a tapered square cup, the effect of process parameters, such as the die gap and blank-holder force, on the occurrence of wrinkling is examined using finite- element simulations. The simulation results show that the larger the die gap, the more severe is the wrinkling, and such wrinkling cannot be suppressed by increasing the blank-holder force. In the analysis of wrinkling that occurred in the stamping of a stepped rectangular cup, an actual production part that has a similar type of geometry was examined. The wrinkles found at the draw wall are attributed to the unbalanced stretching of the sheet metal between the punch head and the step edge. An optimum die design for the purpose of eliminating the wrinkles is determined using finite-element analysis. The good agreement between the simulation results and those observed in the wrinkle-free production part validates the accuracy of the finite-element analysis, and demonstrates the advantage of using finite-element analysis for stamping die design. Keywords: Draw-wall wrinkle; Stamping die; Stepped rec- tangular cup; Tapered square cups 1. Introduction Wrinkling is one of the major defects that occur in the sheet metal forming process. For both functional and visual reasons, wrinkles are usually not acceptable in a finished part. There are three types of wrinkle which frequently occur in the sheet metal forming process: flange wrinkling, wall wrinkling, and elastic buckling of the undeformed area owing to residual elastic compressive stresses. In the forming operation of stamp- ing a complex shape, draw-wall wrinkling means the occurrence Correspondence and offprint requests to: Professor F.-K. Chen, Depart- ment of Mechanical Engineering, National Taiwan University, No. 1 Roosevelt Road, Sec. 4, Taipei, Taiwan 10617. E-mail: fkchenL50560 w3.me.ntu.edu.tw of wrinkles in the die cavity. Since the sheet metal in the wall area is relatively unsupported by the tool, the elimination of wall wrinkles is more difficult than the suppression of flange wrinkles. It is well known that additional stretching of the material in the unsupported wall area may prevent wrinkling, and this can be achieved in practice by increasing the blank- holder force; but the application of excessive tensile stresses leads to failure by tearing. Hence, the blank-holder force must lie within a narrow range, above that necessary to suppress wrinkles on the one hand, and below that which produces fracture on the other. This narrow range of blank-holder force is difficult to determine. For wrinkles occurring in the central area of a stamped part with a complex shape, a workable range of blank-holder force does not even exist. In order to examine the mechanics of the formation of wrinkles, Yoshida et al. 1 developed a test in which a thin plate was non-uniformly stretched along one of its diagonals. They also proposed an approximate theoretical model in which the onset of wrinkling is due to elastic buckling resulting from the compressive lateral stresses developed in the non-uniform stress field. Yu et al. 2,3 investigated the wrinkling problem both experimentally and analytically. They found that wrinkling could occur having two circumferential waves according to their theoretical analysis, whereas the experimental results indi- cated four to six wrinkles. Narayanasamy and Sowerby 4 examined the wrinkling of sheet metal when drawing it through a conical die using flat-bottomed and hemispherical-ended punches. They also attempted to rank the properties that appeared to suppress wrinkling. These efforts are focused on the wrinkling problems associa- ted with the forming operations of simple shapes only, such as a circular cup. In the early 1990s, the successful application of the 3D dynamic/explicit finite-element method to the sheet- metal forming process made it possible to analyse the wrinkling problem involved in stamping complex shapes. In the present study, the 3D finite-element method was employed to analyse the effects of the process parameters on the metal flow causing wrinkles at the draw wall in the stamping of a tapered square cup, and of a stepped rectangular part. A tapered square cup, as shown in Fig. 1(a), has an inclined draw wall on each side of the cup, similar to that existing in a conical cup. During the stamping process, the sheet metal on the draw wall is relatively unsupported, and is therefore 254 F.-K. Chen and Y.-C. Liao Fig. 1. Sketches of (a) a tapered square cup and (b) a stepped rectangular cup. prone to wrinkling. In the present study, the effect of various process parameters on the wrinkling was investigated. In the case of a stepped rectangular part, as shown in Fig. 1(b), another type of wrinkling is observed. In order to estimate the effectiveness of the analysis, an actual production part with stepped geometry was examined in the present study. The cause of the wrinkling was determined using finite-element analysis, and an optimum die design was proposed to eliminate the wrinkles. The die design obtained from finite-element analy- sis was validated by observations on an actual production part. 2. Finite-Element Model The tooling geometry, including the punch, die and blank- holder, were designed using the CAD program PRO/ ENGINEER. Both the 3-node and 4-node shell elements were adopted to generate the mesh systems for the above tooling using the same CAD program. For the finite-element simul- ation, the tooling is considered to be rigid, and the correspond- ing meshes are used only to define the tooling geometry and Fig. 2. Finite-element mesh. are not for stress analysis. The same CAD program using 4- node shell elements was employed to construct the mesh system for the sheet blank. Figure 2 shows the mesh system for the complete set of tooling and the sheet-blank used in the stamping of a tapered square cup. Owing to the symmetric conditions, only a quarter of the square cup is analysed. In the simulation, the sheet blank is put on the blank-holder and the die is moved down to clamp the sheet blank against the blank-holder. The punch is then moved up to draw the sheet metal into the die cavity. In order to perform an accurate finite-element analysis, the actual stressstrain relationship of the sheet metal is required as part of the input data. In the present study, sheet metal with deep-drawing quality is used in the simulations. A tensile test has been conducted for the specimens cut along planes coinciding with the rolling direction (0) and at angles of 45 and 90 to the rolling direction. The average flow stress H9268, calculated from the equation H9268H11005(H9268 0 H11001 2H9268 45 H11001H9268 90 )/4, for each measured true strain, as shown in Fig. 3, is used for the simulations for the stampings of the tapered square cup and also for the stepped rectangular cup. All the simulations performed in the present study were run on an SGI Indigo 2 workstation using the finite-element pro- gram PAMFSTAMP. To complete the set of input data required Fig. 3. The stressstrain relationship for the sheet metal. Draw-Wall Wrinkling in a Stamping Die Design 255 for the simulations, the punch speed is set to 10 m s H110021 and a coefficient of Coulomb friction equal to 0.1 is assumed. 3. Wrinkling in a Tapered Square Cup A sketch indicating some relevant dimensions of the tapered square cup is shown in Fig. 1(a). As seen in Fig. 1(a), the length of each side of the square punch head (2W p ), the die cavity opening (2W d ), and the drawing height (H) are con- sidered as the crucial dimensions that affect the wrinkling. Half of the difference between the dimensions of the die cavity opening and the punch head is termed the die gap (G) in the present study, i.e. G H11005 W d H11002 W p . The extent of the relatively unsupported sheet metal at the draw wall is presumably due to the die gap, and the wrinkles are supposed to be suppressed by increasing the blank-holder force. The effects of both the die gap and the blank-holder force in relation to the occurrence of wrinkling in the stamping of a tapered square cup are investigated in the following sections. 3.1 Effect of Die Gap In order to examine the effect of die gap on the wrinkling, the stamping of a tapered square cup with three different die gaps of 20 mm, 30 mm, and 50 mm was simulated. In each simulation, the die cavity opening is fixed at 200 mm, and the cup is drawn to the same height of 100 mm. The sheet metal used in all three simulations is a 380 mm H11003 380 mm square sheet with thickness of 0.7 mm, the stressstrain curve for the material is shown in Fig. 3. The simulation results show that wrinkling occurred in all three tapered square cups, and the simulated shape of the drawn cup for a die gap of 50 mm is shown in Fig. 4. It is seen in Fig. 4 that the wrinkling is distributed on the draw wall and is particularly obvious at the corner between adjacent walls. It is suggested that the wrinkling is due to the large unsupported area at the draw wall during the stamping process, also, the side length of the punch head and the die cavity Fig. 4. Wrinkling in a tapered square cup (G H11005 50 mm). opening are different owing to the die gap. The sheet metal stretched between the punch head and the die cavity shoulder becomes unstable owing to the presence of compressive trans- verse stresses. The unconstrained stretching of the sheet metal under compression seems to be the main cause for the wrink- ling at the draw wall. In order to compare the results for the three different die gaps, the ratio H9252 of the two principal strains is introduced, H9252 being H9280 min /H9280 max , where H9280 max and H9280 min are the major and the minor principal strains, respectively. Hosford and Caddell 5 have shown that if the absolute value of H9252 is greater than a critical value, wrinkling is supposed to occur, and the larger the absolute value of H9252, the greater is the possibility of wrinkling. The H9252 values along the cross-section MN at the same drawing height for the three simulated shapes with different die gaps, as marked in Fig. 4, are plotted in Fig. 5. It is noted from Fig. 5 that severe wrinkles are located close to the corner and fewer wrinkles occur in the middle of the draw wall for all three different die gaps. It is also noted that the bigger the die gap, the larger is the absolute value of H9252. Consequently, increasing the die gap will increase the possibility of wrinkling occurring at the draw wall of the tapered square cup. 3.2 Effect of the Blank-Holder Force It is well known that increasing the blank-holder force can help to eliminate wrinkling in the stamping process. In order to study the effectiveness of increased blank-holder force, the stamping of a tapered square cup with die gap of 50 mm, which is associated with severe wrinkling as stated above, was simulated with different values of blank-holder force. The blank-holder force was increased from 100 kN to 600 kN, which yielded a blank-holder pressure of 0.33 MPa and 1.98 MPa, respectively. The remaining simulation conditions are maintained the same as those specified in the previous section. An intermediate blank-holder force of 300 kN was also used in the simulation. The simulation results show that an increase in the blank- holder force does not help to eliminate the wrinkling that occurs at the draw wall. The H9252 values along the cross-section Fig. 5. H9252-value along the cross-section MN for different die gaps. 256 F.-K. Chen and Y.-C. Liao MN, as marked in Fig. 4, are compared with one another for the stamping processes with blank-holder force of 100 kN and 600 kN. The simulation results indicate that the H9252 values along the cross-section MN are almost identical in both cases. In order to examine the difference of the wrinkle shape for the two different blank-holder forces, five cross-sections of the draw wall at different heights from the bottom to the line M N, as marked in Fig. 4, are plotted in Fig. 6 for both cases. It is noted from Fig. 6 that the waviness of the cross-sections for both cases is similar. This indicates that the blank-holder force does not affect the occurrence of wrinkling in the stamp- ing of a tapered square cup, because the formation of wrinkles is mainly due to the large unsupported area at the draw wall where large compressive transverse stresses exist. The blank- holder force has no influence on the instability mode of the material between the punch head and the die cavity shoulder. 4. Stepped Rectangular Cup In the stamping of a stepped rectangular cup, wrinkling occurs at the draw wall even though the die gaps are not so significant. Figure 1(b) shows a sketch of a punch shape used for stamping a stepped rectangular cup in which the draw wall C is followed by a step DE. An actual production part that has this type of geometry was examined in the present study. The material used for this production part was 0.7 mm thick, and the stress strain relation obtained from tensile tests is shown in Fig. 3. The procedure in the press shop for the production of this stamping part consists of deep drawing followed by trimming. In the deep drawing process, no draw bead is employed on the die surface to facilitate the metal flow. However, owing to the small punch corner radius and complex geometry, a split occurred at the top edge of the punch and wrinkles were found to occur at the draw wall of the actual production part, as shown in Fig. 7. It is seen from Fig. 7 that wrinkles are distributed on the draw wall, but are more severe at the corner edges of the step, as marked by AD and BE in Fig. 1(b). The metal is torn apart along the whole top edge of the punch, as shown in Fig. 7, to form a split. In order to provide a further understanding of the defor- mation of the sheet-blank during the stamping process, a finite- element analysis was conducted. The finite-element simulation was first performed for the original design. The simulated shape of the part is shown from Fig. 8. It is noted from Fig. 8 that the mesh at the top edge of the part is stretched Fig. 6. Cross-section lines at different heights of the draw wall for different blank-holder forces. (a) 100 kN. (b) 600 kN. Fig. 7. Split and wrinkles in the production part. Fig. 8. Simulated shape for the production part with split and wrinkles. significantly, and that wrinkles are distributed at the draw wall, similar to those observed in the actual part. The small punch radius, such as the radius along the edge AB, and the radius of the punch corner A, as marked in Fig. 1(b), are considered to be the major reasons for the wall breakage. However, according to the results of the finite- element analysis, splitting can be avoided by increasing the above-mentioned radii. This concept was validated by the actual production part manufactured with larger corner radii. Several attempts were also made to eliminate the wrinkling. First, the blank-holder force was increased to twice the original value. However, just as for the results obtained in the previous section for the drawing of tapered square cup, the effect of blank-holder force on the elimination of wrinkling was not found to be significant. The same results are also obtained by increasing the friction or increasing the blank size. We conclude that this kind of wrinkling cannot be suppressed by increasing the stretching force. Since wrinkles are formed because of excessive metal flow in certain regions, where the sheet is subjected to large com- pressive stresses, a straightforward method of eliminating the wrinkles is to add drawbars in the wrinkled area to absorb the redundant material. The drawbars should be added parallel to the direction of the wrinkles so that the redundant metal can be absorbed effectively. Based on this concept, two drawbars are added to the adjacent walls, as shown in Fig. 9, to absorb the excessive material. The simulation results show that the Draw-Wall Wrinkling in a Stamping Die Design 257 Fig. 9. Drawbars added to the draw walls. wrinkles at the corner of the step are absorbed by the drawbars as expected, however some wrinkles still appear at the remain- ing wall. This indicates the need to put more drawbars at the draw wall to absorb all the excess material. This is, however, not permissible from considerations of the part design. One of the advantages of using finite-element analysis for the stamping process is that the deformed shape of the sheet blank can be monitored throughout the stamping process, which is not possible in the actual production process. A close look at the metal flow during the stamping process reveals that the sheet blank is first drawn into the die cavity by the punch head and the wrinkles are not formed until the sheet blank touches the step edge DE marked in Fig. 1(b). The wrinkled shape is shown in Fig. 10. This provides valuable information for a possible modification of die design. An initial surmise for the cause of the occurrence of wrink- ling is the uneven stretch of the sheet metal between the punch corner radius A and the step corner radius D, as indicated in Fig. 1(b). Therefore a modification of die design was carried out in which the step corner was cut off, as shown in Fig. 11, so that the stretch condition is changed favourably, which allows more stretch to be applied by increasing the step edges. However, wrinkles were still found at the draw wall of the cup. This result implies that wrinkles are introduced because of the uneven stretch between the whole punch head edge and the whole step edge, not merely between the punch corner and Fig. 10. Wrinkle formed when the sheet blank touches the stepped edge. Fig. 11. Cut-off of the stepped corner. the step corner. In order to verify this idea, two modifications of the die design were suggested: one is to cut the whole step off, and the other is to add one more drawing operation, that is, to draw the desired shape using two drawing operations. The simulated shape for the former method is shown in Fig. 12. Since the lower step is cut off, the drawing process is quite similar to that of a rectangular cup drawing, as shown in Fig. 12. It is seen in Fig. 12 that the wrinkles were eliminated. In the two-operation drawing process, the sheet blank was first drawn to the deeper step, as shown in Fig. 13(a). Sub- sequently, the lower step was formed in the second drawing operation, and the desired shape was then obtained, as shown in Fig. 13(b). It is seen clearly in Fig. 13(b) that the stepped rectangular cup can be manufactured without wrinkling, by a two-operation drawing process. It should also be noted that in the two-operation drawing process, if an opposite sequence is applied, that is, the lower step is formed first and is followed by the drawing of the deeper step, the edge of the deeper step, as shown by AB in Fig. 1(b), is prone to tearing because the metal cannot easily flow over the lower step into the die cavity. The finite-element simulations have indicated that the die design for stamping the desired stepped rectangular cup using one single draw operation is barely achieved. However, the manufacturing cost is expected to be much higher for the two- operation drawing process owing to the additional die cost and operation cost. In order to maintain a lower manufacturing cost, the part design engineer made suitable shape changes, and modified the die design according to the finite-element Fig. 12.
收藏