鉸鏈落料沖孔復(fù)合模具設(shè)計【說明書+CAD】

鉸鏈落料沖孔復(fù)合模具設(shè)計【說明書+CAD】,說明書+CAD,鉸鏈落料沖孔復(fù)合模具設(shè)計【說明書+CAD】,鉸鏈,沖孔,復(fù)合,模具設(shè)計,說明書,仿單,cad 常州工學(xué)院成人（繼續(xù)）教育學(xué)院 畢業(yè)設(shè)計（論文）任務(wù)書 系： 專業(yè)： 班級： 學(xué)生姓名 指導(dǎo)教師 職稱 課題名稱 鉸鏈落料沖孔復(fù)合模具設(shè)計 課 題 工 作 內(nèi) 容 主要是對鉸鏈落料沖孔復(fù)合模具的加工工藝規(guī)程以及工藝裝備進行設(shè)計 指 標(biāo) ︵ 目 標(biāo) ︶ 要 求 對零件進行工藝分析,擬訂零件的工藝路線,計算各工序的工序內(nèi)容, 設(shè)計指定工序的零件圖，總裝圖，繪制出圖紙（不少于兩張A0），完成設(shè)計說明書 進 程 安 排 3月1日到3月9日對所加工的零件進行工藝分析 3月10日到3月18日擬定工藝路線及確定工序內(nèi)容 3月19日到4月20日完成說明書以及圖紙 4月21日給老師檢查并且修改好所有的設(shè)計 4月25日把所有的設(shè)計交給老師 4月29日答辯 主 要 參 與 文 獻(xiàn) 1.成虹《沖壓工藝與模具設(shè)計》 北京 高等教育出版社 2002 2 王芳《冷沖壓模具設(shè)計指導(dǎo)》 北京 機械工業(yè)出版社 1999 3 王之櫟《機械設(shè)計綜合課程設(shè)計》北京 機械工業(yè)出版社 2003 4 李培根《機械工程基礎(chǔ)》北京 機械工業(yè)出版社 2002 5 胡荊生《公差配合與技術(shù)測量基礎(chǔ)(第二版) 》北京 中國勞動社會保障出版社 2000 6 陳于萍《高曉康編著，互換性與測量技術(shù)》北京 高等教育出版社 2002 7 吳宗澤《機械零件設(shè)計手冊》北京 機械工業(yè)出版社 2003 8 許發(fā)樾《實用模具設(shè)計與制造手冊》北京 機械工業(yè)出版社 1992 地 點 無錫技師學(xué)院 起止 日期 自2007年3月1日 至2007年4月25日 系主任： 指導(dǎo)教師： 年 月 日 年 月 日 摘 要 此次我的畢業(yè)設(shè)計題目是鉸鏈冷沖壓模具設(shè)計，經(jīng)過對這個題目的分析與研究，最終確定了以復(fù)合模沖孔落料（落料與沖Φ8.4孔）→沖Φ10.4孔→預(yù)彎→卷圓→彎曲的工序組合來完成這副模具的設(shè)計。此課題主要詳細(xì)介紹了在鉸鏈冷沖壓模具設(shè)計過程中，對各個工序的設(shè)計構(gòu)想及具體實施方案，并且主要講述模具設(shè)計工藝方案及工藝過程。 由于工作量大，所以此套模具由多人完成，而我設(shè)計的課題是鉸鏈落料沖孔復(fù)合模具設(shè)計，在對沖壓件工藝分析后我進行了方案比較與確定，然后以我自己的課題估算了模具各主要零件（凹模、凸模固定板、墊板，凸模）的外形尺寸，并確定標(biāo)準(zhǔn)模架以及卸料橡膠或彈簧的自由高度等。我設(shè)計的這副落料沖孔模的特點及原則是：首先得保證產(chǎn)品質(zhì)量節(jié)約原材料，降低勞動強度，降低成本，提高勞動生產(chǎn)率，最后達(dá)到產(chǎn)品的要求。 關(guān)鍵詞 冷沖模 復(fù)合模 設(shè)計 目 錄 第一章 概述………………………………………………………………………1 1.1課題的來源與選題依據(jù)…………………………………………………………1 1.1.1課題的意義……………………………………………………………………1 第二章 沖壓工藝過程設(shè)計…………………………………………………1 2.1沖壓件的工藝分析………………………………………………………………2 2.1.1根據(jù)零件的使用條件和技術(shù)要求進行工藝分析……………………………2 2.1.2根據(jù)零件的形狀、尺寸精度和材料進行工藝分析…………………………2 2.1.3材料分析………………………………………………………………………3 2.2沖壓件工藝方案的確定………………………………………………………4 2.2.1沖壓工序類型和工序數(shù)量的確定……………………………………………4 2.2.2工序組合及方案比較…………………………………………………………4 2.2.3各工序模具結(jié)構(gòu)形式的確定…………………………………………………4 2.2.4計算并確定每個工序的形狀和尺寸并繪制各工序圖………………………4 2.2.5 計算各工序的沖壓力，初選壓力機………………………………………9 第三章 沖壓模具設(shè)計………………………………………………………12 3.1 模具結(jié)構(gòu)形式的確定…………………………………………………………12 3.2 計算模具壓力中心，確定模具受力中心的位置………………………………12 3.3 計算或估算模具各主要零件…………………………………………………12 3.4 確定凸、凹模的間隙，計算凸凹模工作部分尺寸…………………………14 3.5 校核壓力機……………………………………………………………………14 結(jié)論………………………………………………………………………………16 致謝………………………………………………………………………………17 參考文獻(xiàn)………………………………………………………………………18 附錄………………………………………………………………………………19 鉸鏈落料沖孔復(fù)合模具設(shè)計 第一章 概述 1.1 課題的來源與選題依據(jù) 1.課題來源：企業(yè)開發(fā)研制產(chǎn)品需要。 選題依據(jù)：根據(jù)學(xué)生所學(xué)專業(yè)及教學(xué)大綱要求，結(jié)合相關(guān)企業(yè)實際生產(chǎn)需要及設(shè)計模式，促使學(xué)生將所學(xué)專業(yè)基礎(chǔ)知識及專業(yè)知識具體應(yīng)用到實踐中，培養(yǎng)其理論聯(lián)系實際的能力。 1.1.1 課題的意義及目的 隨著科學(xué)技術(shù)的不斷進步和工業(yè)生產(chǎn)的迅速發(fā)展，沖壓及模具技術(shù)也在不斷革新與發(fā)展，主要表現(xiàn)在以下幾個方面： 1）工藝分析計算方法現(xiàn)代化 近幾年來，國外開始采用有限變形的彈塑性有限方法，對復(fù)雜成型件的成型過程進行應(yīng)力，應(yīng)變分析的計算機模擬，只預(yù)測某一工藝方案對零件成型的可能性和會發(fā)生的問題，將結(jié)果顯示在圖形的終端上，供設(shè)計人員進行修改和選擇。 2）模具設(shè)計制造現(xiàn)代化 為了加快產(chǎn)品的更新?lián)Q代，縮短模具設(shè)計周期，工業(yè)發(fā)達(dá)國家正在大力開展模具計算機輔助設(shè)計和制造的研究，并已在生產(chǎn)中運用。 3）冷沖壓生產(chǎn)機械化與自動化 為了大量生產(chǎn)的需要，沖壓設(shè)備由低速壓力機發(fā)展到高速自動壓力機。 4）發(fā)展新的成型工藝 為了滿足產(chǎn)品更新?lián)Q代和小批量生產(chǎn)的需要，發(fā)展了一些新的成型工藝，簡易模具，數(shù)控沖壓設(shè)備和沖壓柔性制造技術(shù)等。 5）不斷改進板料的沖壓性能 目前世界各先進工業(yè)國不斷研制出沖壓性能良好的板料，只提高沖壓成型能力和使用效果。 設(shè)計目的： 1）掌握冷沖壓模具的設(shè)計方法，要求我們將理論與實際密切聯(lián)系起來力求所學(xué)知識更完備。 2）培養(yǎng)綜合運用所學(xué)知識，獨立解決實際問題的能力，并提高模具的設(shè)計與制造水平。 3）熟悉查閱有關(guān)資料的手冊的方法，了解成型模具的工藝要求及結(jié)構(gòu)特點。 4）為了使我們?yōu)橐院蟮墓ぷ鞔蛳铝己玫幕A(chǔ)。 第二章 沖壓工藝過程設(shè)計 2.1 沖壓件的工藝分析 2.1.1 根據(jù)零件的使用條件和技術(shù)要求進行工藝分析 該零件(鉸鏈)主要用于電信設(shè)備上零部件的安裝固定以及用于其它地方，可以說用途甚為廣泛。有兩個該零件通過銷一樣的東西將其結(jié)合就形成了鉸鏈，但問題的關(guān)鍵是要注意卷圓部分以及八字孔，而其它部分要求并不是十分嚴(yán)格，只要能達(dá)到產(chǎn)品使用目的就可以。 2.1.2 根據(jù)零件的形狀、尺寸精度和材料進行工藝分析 1 沖裁件的形狀和尺寸 a.該沖裁件形狀簡單、對稱、可采用少廢料直排，提高材料利用率，并且該沖裁件的外形4處交角處采用了圓角過渡，而八字形孔要保證其尖角不允許圓角過渡，但卷圓端部的兩個90°尖角不符合沖裁工藝要求，故需要設(shè)工藝圓角，其圓角值可查《沖壓工藝與模具設(shè)計》 表2.6.1 Rmin=0.35t=0.35×2.5=0.875mm，取Rmin=1mm。 b.因該沖裁件本身就沒有懸臂與狹槽，故不需考慮其最小寬度b。 c.因受模具強度和零件質(zhì)量的限制，沖裁件中孔與孔之間以及孔與零件邊緣之間的壁厚值不能太小，若是太小零件質(zhì)量不易保證。查書《沖壓工藝與模具設(shè)計》圖2.6.2 知必須滿足c≥t ，即c≥2.5，而該沖裁件上Cmin=9-5.2=3.8>c 故滿足要求。 d.沖裁件的孔徑由于受沖孔凸模強度和剛度的限制而不宜太小，否則凸模易折斷和壓彎。該沖裁件的材料為SS400 ，τ =400～510Mpa，查書《沖壓工藝與模具設(shè)計》表2.6.2知自由凸模最小沖孔孔徑d≥1.3t=1.3×2.5=3.25mm，而該零件的最小孔徑d=Φ8.4＞3.25mm 故滿足要求。 e.該零件上尺寸90、70，20、40等都是自由公差按IT14取，尺寸趨近IT14級，而尺寸Φ8.5±0.3、Φ10.4±0.2、Φ8.4±0.2均在IT14級以下，普通沖裁加工可獲得的零件尺寸公差等級可以查《冷沖壓模具設(shè)計指導(dǎo)》表8-19，當(dāng)t=2.5mm時，內(nèi)孔、孔中心距和孔邊距高于IT14，故該沖裁件可以用普通沖裁完成。 2 彎曲工藝性分析 a.彎曲件的最大彎曲圓角半徑可以不加限制，只要措施得當(dāng)控制其回彈量即可，查書《沖壓工藝與模具設(shè)計》表3.3.1 最小相對彎曲半徑Rmin/t的實驗數(shù)值： 當(dāng)彎曲線與板料軋紋方向垂直時Rmin=0.6×2.5=1.5mm； 當(dāng)彎曲線與板料軋紋方向水平時Rmin=1.2×2.5=3mm；而R=5≥Rmin 故滿足要求。 b.由后面尺寸展開計算知直邊L2=18.42mm， 即H=L2=18.42mm＞2t=2×2.5=5mm，故彎曲件的直邊高度也滿足要求。 c.孔邊至彎曲半徑中心的距離L 查《沖壓工藝與模具設(shè)計》P120 圖3.3.14知 L≥2t 而L=26.44-9-8.5-4.2=4.74≤2t=2×2.5=5mm。故不能滿足要求，應(yīng)先彎曲后沖孔。但尺寸相差不大，且考慮該八字形孔是固定螺栓讓孔，形狀和尺寸要求并不是很高，允許有少量的變形，如果重新做模具其成本大大增加，所以綜合考慮仍然采用沖孔落料復(fù)合模。 2.1.3 材料分析 SS400材料分析 寶鋼鋼鐵股份有限公司廠標(biāo) 國家標(biāo)準(zhǔn) Q/BQB 321-2003 GB912-89/GB 3274-88（GB710-91/GB711-88） SS400 Q235、Q245 化學(xué)成分 牌號 公稱厚度 化學(xué)成分 SS400 ≤22.0 C Si Mn P S ≤0.21 ≤0.30 ≤1.40 ≤0.035 ≤0.035 力學(xué)性能 牌號 下屈服強度/MPa （） 抗拉強度/Mpa （） 斷后伸長率 180°彎曲試驗 V型沖擊試驗 Lo=50mm Lo=20mm b=25mm B=40mm b≥35彎心直徑 公稱厚度/mm 公稱厚度/mm 溫度試驗 沖擊功率 ≤16 ＞16 ≤5 ＞ 5～16 ＞16 ≥245 ≥235 400～510 ≥21 ≥17 ≥21 3a — — — — 注： a.拉伸試驗取橫向試樣；屈服現(xiàn)象不明顯，采用Rpa2；對拉伸試驗取Lo=50mm，b=25mm的試樣，即為GB/T228中P14試樣。 b.彎曲試驗取橫向試樣。沖裁試驗時試驗寬度為35mm。 c.沖擊試驗取縱向試樣，沖擊試驗僅適用于厚度不小于12.0mm的產(chǎn)品。 d.WEL-TENS90RE的拉伸試樣取Lo=50mm，b=25mm。 根據(jù)材料分析SS400韌性較好，塑性較好，彈性模量較大（E=206GPa）適宜冷沖壓成形加工。 2.2 確定工藝方案 2.2.1 沖壓工序類型和工序數(shù)量的確定 該零件為電信設(shè)備上零部件的安裝固定，故該零件為中批量生產(chǎn)，工藝性較好，可以從零件圖上直觀確定該沖裁件所需的基本工序有：落料、沖孔、預(yù)彎、卷圓、彎曲。 2.2.2 工序組合及方案比較 方案一：落料→沖Φ8.4孔→沖Φ10.4孔→預(yù)彎→卷圓→彎曲。 方案二：復(fù)合模沖孔落料（落料與沖Φ8.4孔）→沖Φ10.4孔→預(yù)彎→卷圓→彎曲。 方案三：落料與沖8字形孔的級進?！A(yù)彎→卷圓→彎曲。 方案比較： 方案一：此方案需要6副模具，工作量較大，較煩瑣，成本較高，生產(chǎn)率低。 方案二：雖然此方案要5副模具才能完成，但相對方案一6套模具來說已經(jīng)減輕工作量，并且每副模具都較簡單，而且加工質(zhì)量比較好，成本也較低。 方案三：雖然此方案只需要4副模具，但第一副模具是涉及級進模，此副模具結(jié)構(gòu)較復(fù)雜，而且制造成本較高，同時沖孔時沖孔的質(zhì)量比較差，沒有方案二的沖孔質(zhì)量好；八字孔一次成型，孔與孔連接處應(yīng)力較集中，影響模具強度。 綜合考慮：采用方案二 2.2.3 各工序模具結(jié)構(gòu)形式的確定 工序Ⅰ 沖孔落料復(fù)合模，采用倒裝式。 工序Ⅱ 沖孔模，采用順裝，鑲套式凹模，下漏料。 工序Ⅲ 彎曲預(yù)彎R圓角，順裝，帶頂板校正彎曲。 工序Ⅳ 彎曲模卷圓R圓角，立式卷圓模。 工序Ⅴ 彎曲模成形彎曲，順裝，帶頂板校正彎曲。 2.2.4 計算并確定每個工序的形狀和尺寸，繪制各工序圖、排樣圖，并且計算材料利用率 1.復(fù)合模（沖外形及2-?8.4±0.2孔） 1) 計算彎曲件毛坯展開尺寸 該零件圓角半徑為R=5mm 查書《沖壓工藝與模具設(shè)計》知道 R=5＞0.5t=0.5×0.25=1.25mm 故選單向彎曲件的毛坯展開長度計算公式為： 因 查書《沖壓工藝與模具設(shè)計》表3.3.3知道 x=0.38 因r / t =4.25/2.5 =1.7 查書《沖壓工藝與模具設(shè)計》表3.3.5知道 k=0.61 則卷圓部分 圖2-1-1 毛坯彎曲圖 圖2-1-2 彎曲角度 可得L1=26.44mm L2=18.42mm 所以毛坯展開尺寸為L=L1+L2+L3+L4=26.44+18.42+4.67+30.24=79.77mm 因零件彎曲成形時材料伸長趨勢影響故取L=79.8mm。 圖2-2 毛坯展開圖 2) 確定排樣方案 搭邊和條料寬度的確定 查書《沖壓工藝與模具設(shè)計》表2.5.2因工件材料t=2.5mm且為矩形工件 L＞50mm,知a1=2.5,a2=2.8考慮補償定位誤差，保持條料有一定的剛度可取 a1=3mm ,a=3mm 條料寬度的確定。 δ、c查表2.5.3知 δ=0.8 c=0.4 此處為無側(cè)壓裝置則＝＝ 取。 按制件在材料上的排列來看排樣方案取為直排,詳見排樣圖 圖2-3 排樣圖 3）計算材料利用率 2.沖孔模（工序圖） 3.預(yù)彎（工序圖） 由前面尺寸展開計算知L1=26.44mm，L2=19.42mm，L3=4.67mm 設(shè)L5(225°圓弧長)，查書《沖壓工藝與模具設(shè)計》表3.3.5知道 k=0.61 4．卷圓（工序圖） 5.零件圖 2.2.5 計算各工序的沖壓力，初選壓力機 1）復(fù)合模沖孔落料 沖裁力計算 該零件材料為SS400 取 落料 查書《沖壓模具設(shè)計指導(dǎo)》表2-20知 =0.04 = F落料=89775+3591=93366 沖Φ8.4孔 查書《沖壓模具設(shè)計指導(dǎo)》表2-20知 =0.04 = 初選壓力機 J23-16 2）沖Φ10.4孔 查書《沖壓模具設(shè)計指導(dǎo)》表2-20知 =0.04 = 初選壓力機 J23-10 3）預(yù)彎 按校正彎曲時的彎曲力計算 查書《沖壓模具設(shè)計指導(dǎo)》表3.3.6知 q=40～60 MPa取q=60MPa A≤6.25×63=393.75（彎曲件被校正部分的投影面積） =q×A=60×393.75=23625N 初選壓力機 J23-10 4）卷圓 按自由彎曲時的V形彎曲件彎曲力計算 查書《沖壓模具設(shè)計指導(dǎo)》（3.3.14）知k=1.3 ===20475N 式中b為彎曲件的寬度（mm）；t為彎曲件的厚度（mm）；r為內(nèi)圓彎曲半徑（mm）；為彎曲件的抗拉強度（MPa）；K為安全系數(shù)，一般取1.3。 初選壓力機 J23-10 5）彎曲 按校正彎曲時的彎曲力計算 查書《沖壓模具設(shè)計指導(dǎo)》表3.3.6知 q=40～60 MPa取q=60MPa A≤4.36×63=274.68N（彎曲件被校正部分的投影面積） =q×A=60×274.68=16480.8N 初選壓力機 J23-10 沖壓工藝過程卡見附錄 第三章 沖壓模具設(shè)計 3.1 模具結(jié)構(gòu)形式的確定 我所設(shè)計的是鉸鏈落料沖孔（Φ8.4）復(fù)合模具，經(jīng)分析：我采用倒裝復(fù)合模，它的定位方式可以采用一個固定擋料釘做步擋釘定距，兩個活動擋料釘做側(cè)擋釘導(dǎo)料，卸料方式可以采用彈壓卸料，剛性打料推件，詳情見模具工裝設(shè)計圖。 3.2 計算模具壓力中心，確定模具受力中心的位置 落料工序圖中考慮到倒圓角，由于計算較復(fù)雜且要求并不是太嚴(yán)格，所以我們將其近似看成是直線，以直線計算較方便，圖見工序圖 圖3-1 零件圖 各點坐標(biāo)： A（0，22.5） B（13.015，0） C（32.78，38.25） D（60.29，31.5） E（79.8，15.75） 零件關(guān)于X軸對稱 所以模具的壓力中心為 （33.8 , 0） 該零件左右對稱中心坐標(biāo)為（39.9，0）與（33.8 , 0）相差不大，在模柄范圍內(nèi)，為使模具結(jié)構(gòu)對稱，降低模具材料成本，選模具的壓力中心為（39.9，0）。 3.3 計算或估算模具各主要零件（凹模、凸模固定板、墊板，凸模）的外形尺寸，并確定標(biāo)準(zhǔn)模架以及卸料橡膠或彈簧的自由高度等。 1．設(shè)計凹模的外形尺寸 查書《沖壓工藝與模具設(shè)計》表2.8.2知系數(shù)k=0.35 凹模外形尺寸 綜合考慮并查冷沖模國家標(biāo)準(zhǔn) 取 即凹模尺寸 （—） 凹模材料可以選用W6Mo5Cr4V2。 2．設(shè)計主要零部件外形尺寸 1）墊板 墊板的作用是承受凸?；虬寄５膲毫Γ乐惯^大的沖壓力在上、下模座上壓出凹坑，影響模具正常工作，墊板厚度根據(jù)壓力機大小選擇，一般取。而此副模具上墊板需考慮打板活動量，故取 而下墊板可按冷沖模國家標(biāo)準(zhǔn)查取 ，而墊板的外形尺寸與凹模輪廓尺寸基本一致 則，材料為45鋼，熱處理后硬度為。 則 上墊板尺寸 下墊板尺寸 （—） 2）固定板 固定板主要用于小型凸模或凸凹模等工作零件的固定，固定板的外形與凹模輪廓尺寸一致，厚度取即 取，材料可選Q235或45鋼。則上、下固定板尺寸 （—） 3）卸料板 卸料板外形尺寸考慮安裝條料縱向送料的擋料釘，寬度尺寸需放大，并且根據(jù)排樣圖上擋料釘位置尺寸取其寬度 ，長度仍與凹模一致，即 ， 厚度按冷沖模國家標(biāo)準(zhǔn)取 ，則卸料板的尺寸 4）卸料橡皮的自由高度 根據(jù)工件材料厚度，沖裁時凸模進入凹模深度取2mm考慮模具維修時刃磨量再考慮開啟時卸料板高出凸模，則總的工作行程 ，取，模具在組裝時橡皮的預(yù)壓量為 取 5）模架的選擇 查中華人民共和國國家標(biāo)準(zhǔn)GB2851～2875-81冷沖模.1984-01-01實施.國家標(biāo)準(zhǔn)總局 批準(zhǔn) 選冷沖?；瑒訉?dǎo)向模架中間導(dǎo)柱模架 250×200×220～265 GB2851.5-81 3.4 確定凸、凹模的間隙，計算凸凹模工作部分尺寸 1）查書《沖壓工藝與模具設(shè)計》表2.2.3 知 沖裁件精度在IT14時 也可以查書《沖壓工藝與模具設(shè)計》表2.3.1 設(shè)凸、凹模分別按IT6，IT7級加工制造，則 落料 展開尺寸試模修正 沖孔 孔距尺寸 = 落料凸凹模的基本尺寸與凹模相同，分別是62.7mm，89.6mm，79.8mm,8.4mm，不必標(biāo)注公差，但要注明以0.36～0.5mm的雙面間隙與落料凹模配做。 3.5 校核壓力機 初選壓力機型號為J23-16，該壓力機最大閉合高度為220mm，而模具的總閉合高度為250mm，由這一條就可以說明：初選型號為 J23-16的壓力機不能滿足要求，故改選型號為 JH21-60的壓力機。 該壓力機的主要技術(shù)規(guī)格 公稱壓力/KN 600 公稱壓力行程/mm 4 滑塊行程/mm 140 行程次數(shù)/次 70 最大閉合高度/mm 300 閉合高度調(diào)節(jié)量/mm 70 滑塊中心線到機身距離/mm 270 工作臺尺寸/mm 870×520 (左右×前后) 工作臺孔尺寸/mm 150 模柄孔尺寸/mm 50×60 (直徑×深度) 電機功率/kw 5.5 1.是否滿足＞＞ 1.模具總閉合高度 由壓力機 JH21-60 知道 由＞＞知 ＞＞ ＞＞ 所以滿足要求 2.公稱壓力是否大于沖壓計算的總壓力，即≥ ≥ 所以滿足要求 3.滑塊行程是否滿足沖壓件的成形要求 所選壓力機滑塊行程為140mm 而沖裁此零件的行程只需約6mm遠(yuǎn)遠(yuǎn)小于140mm 所以滿足要求 4.工作臺尺寸是否大于模具尺寸 所選壓力機工作臺尺寸/mm 870×520 (左右×前后) 而模具為 480×280 所以工作臺尺寸每邊肯定大于70mm，并且工作臺墊板孔能保證廢料漏下。 因此滿足要求 根據(jù)上面計算綜合考慮課題設(shè)計（復(fù)合模落料、沖孔）等條件以及其他因素 壓力機選 JH21系列開式固定臺壓力機 選壓力機型號為 JH21-60 結(jié) 論 時光匆匆而逝，我的多年學(xué)習(xí)生活也即將結(jié)束，為了更好的適應(yīng)以后的工作，培養(yǎng)我們能運用所學(xué)的專業(yè)知識獨立解決實際生產(chǎn)問題的能力，以及鞏固和擴大課堂教學(xué)內(nèi)容提高工藝計算機械制圖的各科設(shè)計資料的能力，為今后工作崗位從事專業(yè)工作擬定出更為經(jīng)濟合理的制造工藝及設(shè)計模具打下良好的基礎(chǔ)，在此基礎(chǔ)上我們進行了兩個月的畢業(yè)設(shè)計。 通過此次冷沖模設(shè)計是我知道：冷沖模是建立在金屬塑性變形的基礎(chǔ)上，在常溫下利用安裝在壓力機上的模具對材料施加壓力，使其產(chǎn)生分離或塑性變形從而獲得一定形狀、尺寸和性能的零件的一種壓力加工方法。并且，通過這次冷沖模設(shè)計，使我重新溫習(xí)了以前所學(xué)過的有關(guān)機械方面的知識，并且通過查閱資料了解了一些新的知識，使我對模具設(shè)計有了初步的了解。 致 謝 時間過的真快，轉(zhuǎn)眼幾個星期過去了，我的畢業(yè)設(shè)計也將結(jié)束，仍清楚記得拿到畢業(yè)設(shè)計課題時，不知如何下手的尷尬場景。 在此，我首先要感謝這么多年來能讓我認(rèn)真學(xué)習(xí)的母校——無錫技師學(xué)院，要感謝我的指導(dǎo)老師柴俊在畢業(yè)設(shè)計選題以及研究方法上給予的悉心指導(dǎo)，老師的學(xué)識令我受益匪淺。同時也要感謝蔡昀老師對我畢業(yè)設(shè)計的幫助。最后再次感謝柴俊、蔡昀老師。 參考文獻(xiàn) [1] 成虹《沖壓工藝與模具設(shè)計》 北京 高等教育出版社 2002 [2] 王芳《冷沖壓模具設(shè)計指導(dǎo)》 北京 機械工業(yè)出版社 1999 [3] 王之櫟《機械設(shè)計綜合課程設(shè)計》北京 機械工業(yè)出版社 2003 [4] 李培根《機械工程基礎(chǔ)》北京 機械工業(yè)出版社 2002 [5] 胡荊生《公差配合與技術(shù)測量基礎(chǔ)(第二版) 》北京 中國勞動社會保障出版社 2000 [6] 陳于萍《高曉康編著，互換性與測量技術(shù)》北京 高等教育出版社 2002 [7] 吳宗澤《機械零件設(shè)計手冊》北京 機械工業(yè)出版社 2003 [8] 許發(fā)樾《實用模具設(shè)計與制造手冊》北京 機械工業(yè)出版社 1992 [9] 朱傳禮 林蒲生《高等學(xué)校畢業(yè)設(shè)計論文指導(dǎo)手冊機械卷》北京 高等教育出版社 1998 [10] 《中華人民共和國國家標(biāo)準(zhǔn)GB2851～2875-81冷沖模》1984-01-01實施 國家標(biāo)準(zhǔn)總局 批準(zhǔn) 17 Int 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.