T型墊板沖壓工藝分析與模具設(shè)計(jì)【說(shuō)明書(shū)+CAD】,說(shuō)明書(shū)+CAD,T型墊板沖壓工藝分析與模具設(shè)計(jì)【說(shuō)明書(shū)+CAD】,墊板,沖壓,工藝,分析,模具設(shè)計(jì),說(shuō)明書(shū),仿單,cad 摘 要 本套模具設(shè)計(jì)是墊板沖裁模的設(shè)計(jì)及加工制造全過(guò)程。墊板的作用是承受凸?；虬寄５妮S向壓力。為了保證模具的正常工作一般采用5-12mm,外形尺寸與固定板相同。 設(shè)計(jì)內(nèi)容是從零件的工藝性分析開(kāi)始的。根據(jù)工藝要求來(lái)確定設(shè)計(jì)的大體思路計(jì)算出利用率、壓力、推件力…….主要零部件包括凸模凹模以及其他的如定位零件、卸料板、導(dǎo)柱導(dǎo)套等。 通過(guò)對(duì)零件的了解可知有沖孔和落料2個(gè)工序。材料為10號(hào)鋼，具有良好的沖裁性能，適宜沖裁。工件外形結(jié)構(gòu)簡(jiǎn)單，形狀規(guī)則，生產(chǎn)批量為大批量生產(chǎn)，再經(jīng)過(guò)方案比較，故選擇復(fù)合沖裁作為該副模具工藝生產(chǎn)方案即比較加工又便于經(jīng)濟(jì)；經(jīng)過(guò)計(jì)算分析完成該模具的主要設(shè)計(jì)計(jì)算；選出符合該模具的定位方式、卸料出件方式導(dǎo)向方式；設(shè)計(jì)模具的工作部分即凸、凹模的設(shè)計(jì)，選擇模具的材料即確定每個(gè)零部件的加工方案；僅接著根據(jù)模具的裝配原則，完成模具的裝配裝配模具試沖通過(guò)試沖可以發(fā)現(xiàn)模具設(shè)計(jì)和制造的不足，并找出原因給予糾正，并對(duì)模具進(jìn)行適當(dāng)?shù)恼{(diào)整和修理。 關(guān)鍵詞：墊板 模具 沖壓 II 引 言 引 言 模具生產(chǎn)的工藝及科技含量的高低，已成為衡量一個(gè)國(guó)家科技與產(chǎn)品制造水平的重要標(biāo)志，它在很大程度上決定產(chǎn)品的質(zhì)量，效益，決定著一個(gè)國(guó)家制造業(yè)的國(guó)際競(jìng)爭(zhēng)力。 鑒于模具在國(guó)民經(jīng)濟(jì)的發(fā)展有十分的重要的地位和作用。國(guó)家頒布了(《關(guān)于當(dāng)前產(chǎn)業(yè)政策要點(diǎn)的決定》中，把模具列為機(jī)械工業(yè)技術(shù)改造序列第一位、生產(chǎn)和基本建設(shè)序列第二位。當(dāng)前要加強(qiáng)技術(shù)改革創(chuàng)新完善體系。 在信息化帶動(dòng)工業(yè)化發(fā)展的今天，在經(jīng)濟(jì)全球化趨向日漸加速的情況下，我國(guó)沖壓模具必須盡快提高水平。通過(guò)改革與發(fā)展，采取各種有效措施，在沖壓模具行業(yè)全體職工的共同努力奮斗之下，逐漸縮小與世界先進(jìn)水平的差距?！笆晃濉逼陂g，在科學(xué)發(fā)展觀指導(dǎo)下，不斷提高自主開(kāi)發(fā)能力、重視創(chuàng)新、堅(jiān)持改革開(kāi)放、走新型工業(yè)化道路，將速度效益型的增長(zhǎng)模式逐步轉(zhuǎn)變到質(zhì)量和水平效益型軌道上來(lái)，我國(guó)的沖壓模具的水平也必然會(huì)更上一層樓。 T型墊板沖壓模具設(shè)計(jì) 目 錄 摘 要 I 引 言 II 目 錄 III 1 沖壓件的工藝性分析與方案確定 1 1.1 沖壓件工藝性分析 1 1.2 沖裁工藝方案的確定 2 2 主要設(shè)計(jì)計(jì)算 2 2.1 排樣方案的確定及計(jì)算 2 2.2 沖壓力的計(jì)算 3 2.3 壓力中心的確定及相關(guān)計(jì)算 5 2.4 工作零件刃口尺寸計(jì)算 6 3 模具總體設(shè)計(jì) 8 3.1 模具類(lèi)型的選擇 8 3.2 定位方式的選擇 8 3.3 卸料﹑出件方式的選擇 8 3.4 導(dǎo)向方式的選擇 9 4 凸模、凹模、凸凹模的結(jié)構(gòu)設(shè)計(jì) 9 4.1 凸模結(jié)構(gòu)的設(shè)計(jì) 9 4.2 凹模結(jié)構(gòu)的設(shè)計(jì) 9 4.3 凸凹模的的結(jié)構(gòu)設(shè)計(jì) 10 5 模具材料的選用和模架的選擇 11 5.1 模具材料的選用 11 5.2 模架的選擇 13 6 主要零部件的設(shè)計(jì) 13 6.1 定位零件的設(shè)計(jì) 13 6.2 導(dǎo)料板的設(shè)計(jì) 14 6.3 卸料部件的設(shè)計(jì) 14 7 模具總裝圖 14 8 沖壓設(shè)備的選擇 16 9 模具的裝配和工作過(guò)程 16 9.1 模具的裝配 16 9.2 模具的工作過(guò)程 17 結(jié) 論 18 致 謝 19 參考文獻(xiàn) 20 21 1 沖壓件的工藝性分析與方案確定 1.1 沖壓件工藝性分析 工件名稱(chēng)：墊板 零件簡(jiǎn)圖：如圖1所示 生產(chǎn)批量：大批量 材 料：10鋼 材料厚度： 圖1 零件圖 沖壓件的工藝性是指沖壓件對(duì)沖壓工藝的適應(yīng)性。在一般情況下，對(duì)沖壓件工藝性影響最大的幾何形狀尺寸和精度要求。良好的沖壓工藝性應(yīng)能滿(mǎn)足材料較省、工序較少、模具加工較容易、壽命較高、操作方便及產(chǎn)品質(zhì)量穩(wěn)定等要求。 ⑴ 沖裁件的形狀應(yīng)能符合材料合理排樣，減少?gòu)U料。 ⑵ 沖裁各直線(xiàn)或曲線(xiàn)的連接處，宜有適當(dāng)?shù)膱A角。 ⑶ 沖裁件凸出或凹入部分寬度不宜太小，并應(yīng)避免過(guò)長(zhǎng)的懸臂與窄槽。 ⑷ 腰圓形沖裁件，如允許圓弧半徑，則R應(yīng)大于料寬的一半，即能采用少?gòu)U料排樣；如限定圓弧半徑等于工件寬度之半，就不能采用少?gòu)U料排樣，否則會(huì)有臺(tái)肩產(chǎn)生。 ⑸ 沖孔時(shí)，由于受到凸模強(qiáng)度的限制，孔的尺寸不宜過(guò)小。 此工件只有落料和沖孔兩個(gè)工序。材料為10號(hào) 鋼良好的沖壓性能，適合沖裁。該零件形狀簡(jiǎn)單、對(duì)稱(chēng)，是由圓弧和直線(xiàn)組成的。根據(jù)所標(biāo)注的尺寸公差可知，沖裁件內(nèi)外形所能達(dá)到的經(jīng)濟(jì)精度為，工件的未標(biāo)注尺寸全部為自由公差，可看作IT14級(jí)，孔中心與邊緣距離尺寸公差為。將以上精度與零件簡(jiǎn)圖中所標(biāo)注的尺寸公差相比較，可認(rèn)為該零件的精度要求能夠在沖裁加工中得到保證。其它尺寸標(biāo)注、生產(chǎn)批量等情況，也均符合沖裁的工藝要求。 1.2 沖裁工藝方案的確定 該工件包括落料、沖孔兩個(gè)基本工序，可有以下三種工藝方案。 方案一：先落料，后沖孔。采用單工序模生產(chǎn)。 方案二：先落沖孔復(fù)合沖壓。采用復(fù)合模生產(chǎn)。 方案三：沖孔—落料級(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，但需要兩道工序兩副模具，成本較高而生產(chǎn)效率低，難以滿(mǎn)足大批量生產(chǎn)要求。 方案二只需一副模具，工件的精度及生產(chǎn)效率都較高，制造難不大，成本相對(duì)比較低些，并且操作十分方便工件精度也能滿(mǎn)足要求。 方案三也只需一副模具，生產(chǎn)效率高，操作方便，工件精度也能滿(mǎn)足要求但由于本副模具比較簡(jiǎn)單，僅有沖一個(gè)的孔采用該方案造價(jià)相對(duì)比較高，由于需要再定位裝置精度很難達(dá)到工件上所標(biāo)注的尺寸公差，故而采用該方案不符合市場(chǎng)經(jīng)濟(jì)規(guī)律（降低成本提高生產(chǎn)效率）。 通過(guò)對(duì)上述三種方案的分析比較，該件的沖壓生產(chǎn)采用方案二復(fù)合沖裁為佳。 2 主要設(shè)計(jì)計(jì)算 2.1 排樣方案的確定及計(jì)算 設(shè)計(jì)復(fù)合模，首先要設(shè)計(jì)條料的排樣圖。墊板的形狀具有一頭大一頭小的特點(diǎn)，直排樣時(shí)材料利用率低，應(yīng)采用直隊(duì)排樣，如圖2所示的排樣方法，設(shè)計(jì)成隔位沖壓，可顯著地減少?gòu)U料。隔位沖壓就是將第一遍沖壓以后的條料水平方向旋轉(zhuǎn)1800，再?zèng)_第二遍，在第一次沖裁的間隙中沖裁出第二部分工件。搭邊值取由表2.1查得最小搭邊值：。表1 最小搭邊值a 卸料板型式 條料厚度t/mm 搭邊值/mm 用于圓形及r>2t 用于矩形 L<50 用于矩形 L>50 a a1 a a1 a a1 彈性卸料板 ~0.25 1.2 1.0 1.5 1.2 1.8~2.6 1.5~2.5 0.25~0.5 1.0 0.8 1.2 1.0 1.5~2.5 1.2~2.2 0.5~1.0 1.8~2.6 1.5~2.5 1.0~1.5 1.3 1.0 1.5 1.2 2.2~3.2 1.8~2.8 1.5~2.0 1.5 1.2 1.8 1.5 2.4~3.4 2.0~3.0 圖2 排樣圖 計(jì)算沖壓件毛坯面積： 條料寬度： 布距： 一個(gè)步距距的材料利用率： 式中一個(gè)布距內(nèi)沖裁件數(shù)目 沖裁件面積 條料寬度 布距 2.2 沖壓力的計(jì)算 平刃口模具沖裁時(shí)，其理論沖裁力（N） 可按下式計(jì)算： 式中： 沖裁件周長(zhǎng) 材料厚度 材料抗剪強(qiáng)度 材料抗剪強(qiáng)度，材料厚度 ⑴ 落料力 ⑵ 沖孔力 ⑶ 落料時(shí)的卸料力 查表2.2：取 表2 卸料力、頂件力、推件力系數(shù) 材料及厚度/mm 鋼 0.065~0.075 0.1 0.14 0.1~0.5 0.045~0.055 0.065 0.08 0.5~2.5 0.04~0.05 0.055 0.06 2.5~6.5 0.03~0.04 0.045 0.05 >6.5 0.02~0.03 0.025 0.03 鋁、鋁合金 0.025~0.08 0.03~0.07 紫銅、黃銅 0.02~0.06 0.03~0.09 故 ⑷ 沖孔時(shí)的推件力 取圖3的凹模刃口形式，，則個(gè) 查表2.1： 故 選擇沖床時(shí)的總沖壓力為： 該模具采用彈性卸料和下出料方式。 根據(jù)計(jì)算結(jié)果，沖壓設(shè)備擬選J23-40。 圖3 凹模刃口形式 圖4 壓力中心 2.3 壓力中心的確定及相關(guān)計(jì)算 確定模具壓力中心按比例畫(huà)出零件形狀，選坐標(biāo)系，如圖4所示。因零件左右對(duì)稱(chēng)，即，故只需計(jì)算。 將工件沖裁周邊分成基本線(xiàn)段，求出各段長(zhǎng)度及各段的重心位置： 故壓力中心C坐標(biāo)為：（0，46.27） 有以上計(jì)算結(jié)果可看以出，若選用J23-40沖床，C點(diǎn)仍在壓力機(jī)模柄孔投影面積范圍內(nèi)，滿(mǎn)足要求。 2.4 工作零件刃口尺寸計(jì)算 在確定工件零件刃口尺寸計(jì)算方法之前，首先要考慮工作零件的加工方法及模具裝配方法。結(jié)合該模具的特點(diǎn)，工作零件的形狀相對(duì)比較簡(jiǎn)單，適宜采用線(xiàn)切割機(jī)床分別加工落料凸模、凹模、凸模固定板以及卸料板，這種加工方法可以保證這些零件各孔的同軸度，使裝配工作簡(jiǎn)化。因此工作零件刃口尺寸計(jì)算就按分開(kāi)加工的方法計(jì)算。查表2.3得間隙值 ，。 表3初始雙面間隙Zmax、Zmin 材料厚度t/mm 08、10、35 09M2、Q235 Q345 40、50 65Mn Zmax Zmin Zmax Zmin Zmax Zmin Zmax Zmin <0.5 極小間隙 0.5 0.040 0.060 0.040 0.060 0.040 0.060 0.040 0.060 0.6 0.0.048 0.072 0.048 0.072 0.048 0.072 0.048 0.072 0.7 0.064 0.092 0.064 0.092 0.064 0.092 0.064 0.092 對(duì)沖孔 ，其凸、凹模刃口部分尺寸計(jì)算如下： 查表2.4的凸、凹模制造公差： 表4 規(guī)則形狀沖裁時(shí)凸模、凹模的制造公差 基本尺寸 凸模公差 凹模公差 基本尺寸 凸模公差 凹模公差 0.020 0.020 180-260 0.030 0.045 >18-30 0.020 0.025 260-360 0.035 0.050 30～80 0.020 0.030 360-500 0.040 0.060 80～120 0.025 0.035 >500 0.050 0.070 120～180 0.030 0.040 校核： 滿(mǎn)足 條件 查表2.5得因數(shù) 按式 表5 磨損系數(shù) 材料厚度t/mm 非圓形沖件 圓形沖件 1 0.75 0.5 0.75 0.5 沖件公差Δ/mm 1 <0.16 0.17~0.35 >0.36 <0.16 >0.16 1~2 <0.20 0.21~0.41 >0.42 <0.20 >0.20 2~4 <0.24 0.25~0.49 >0.50 <0.24 >0.24 4~ <0.30 0.31~0.59 >0.60 <0.30 >0.30 對(duì)外輪廓的落料，由于形狀較復(fù)雜，故采用分開(kāi)加工方法，其凸、凹模刃口部分尺寸計(jì)算如下： 當(dāng)以凹模為基準(zhǔn)件時(shí)，凹模磨損后，刃口部分尺寸都增大，因此均屬于A類(lèi)尺寸。零件圖中未注公差的尺寸，查查表2.6找出其極限偏差： 表6 沖裁件外徑與內(nèi)孔尺寸公差 料厚/mm 沖件尺寸/mm 0.2~0.5 0.5~1 1~2 2~4 4~6 一般精度 沖裁件 〈10 0.08/0.05 0.12/0.05 0.18/0.06 0.24/0.03 0.30/0.01 10~50 0.10/0.08 0.16/0.08 0.22/0.10 0.28/0.12 0.35/0.15 50~150 0.14/0.12 0.22/0.22 0.30/0.16 0.40/0.20 0.50/0.25 150~300 0.2 0.3 0.5 0.7 1.0 較高精度 沖裁件 〈10 0.025/0.02 0.03/0.02 0.04/0.03 0.06/0.04 0.10/0.06 10~50 0.03/0.04 0.04/0.04 0.06/0.06 0.08/0.08 0.12/0.10 50~150 0.05/0.08 0.06/0.08 0.08/0.10 0.10/0.12 0.15/0.15 150~300 0.08 0.10 0.12 0.15 0.20 查表2.5得因數(shù)為：當(dāng) 時(shí), 當(dāng) 時(shí), 按式： 3 模具總體設(shè)計(jì) 3.1 模具類(lèi)型的選擇 模具類(lèi)型分為三種分別是：?jiǎn)喂ば蚰?、?fù)合模和級(jí)進(jìn)模。 單工序模又稱(chēng)簡(jiǎn)單沖裁模，是指在壓力機(jī)一次行程內(nèi)只完成一種沖裁工序的模具，如落料模、沖孔模、切斷模切口模等。 復(fù)合模是指在一次壓力機(jī)的行程中在模具的同一工位上同時(shí)完成兩道或兩到以上不同沖裁工序的模具。復(fù)合模是一種多工序沖裁模，它在結(jié)構(gòu)上的主要特征是有一個(gè)或幾個(gè)具有雙重作用的工作零件——凸凹模，如落料沖孔復(fù)合模中有一個(gè)既能作落料凸模又能作沖孔凹模的凸凹模。 級(jí)進(jìn)模是指壓力機(jī)在一次行程中依次在模具幾個(gè)不同位置 同時(shí)完成多道沖壓工序。 由沖壓工藝分析可知，該模具采用復(fù)合沖壓，所以模具類(lèi)型為復(fù)合模。 3.2 定位方式的選擇 定位方式的選擇通俗的說(shuō)既是選擇定位零件。定位零件的作用是使坯料或工序件在模具上有正確的位置，定位零件的結(jié)構(gòu)形式很多，用于對(duì)條料進(jìn)行定位的定位零件有擋料銷(xiāo)、導(dǎo)料銷(xiāo)、導(dǎo)料板、側(cè)壓裝置、導(dǎo)正銷(xiāo)、側(cè)刃等，用于對(duì)工序進(jìn)行定位的定位零件有定位銷(xiāo)、定位板等。 定位零件基本上都已標(biāo)準(zhǔn)化，可根據(jù)坯料和工序件形狀、尺寸、精度及模具的結(jié)構(gòu)形式與生產(chǎn)效率要求等選用相應(yīng)的標(biāo)準(zhǔn)。 因?yàn)樵撃＞卟捎檬菞l料，控制條料的送進(jìn)方向采用導(dǎo)料板，無(wú)側(cè)壓裝置?？刂茥l料的送進(jìn)步距采用擋料銷(xiāo)初定距，導(dǎo)正銷(xiāo)精定距。而第一件的沖壓位置因?yàn)闂l料長(zhǎng)度有一定余量，可以靠操作工目測(cè)定。 3.3 卸料﹑出件方式的選擇 卸料與出件裝置的作用是當(dāng)沖模完成一次沖壓之后，把沖件或廢料從模具工作零件上卸下來(lái)，以便沖壓工作繼續(xù)進(jìn)行。通常，把沖件或廢料從凸模上卸下來(lái)稱(chēng)為卸料。 卸料裝置按卸料的方式分為固定卸料裝置﹑彈性卸料裝置和廢料切刀三種。固定卸料裝置僅由固定卸料板構(gòu)成，一般安裝在下模的凹模上；彈性卸料裝置由卸料板、卸料螺釘和彈性元件（彈簧或橡膠）組成；彈性卸料裝置可安裝于上?；蛳履?，依靠彈簧或橡膠的彈力來(lái)卸料，卸料力不太大但沖壓時(shí)可兼起壓料作用，故多用于沖裁料薄及平面度要求較高的沖件；廢料切刀是在沖裁過(guò)程中沖裁廢料切斷成數(shù)塊，從而實(shí)現(xiàn)卸料的一種卸料零件。 出件裝置的作用是從凹模內(nèi)卸下沖件或廢料。我們通常把準(zhǔn)過(guò)載上模內(nèi)的出件裝置稱(chēng)為推件裝置；把裝在下模內(nèi)的稱(chēng)為頂件裝置。 綜合考慮該模具的結(jié)構(gòu)和使用方便，以及工件料厚為2.2mm，相對(duì)較薄，卸料力也比較小，故可采用彈性卸料，又因?yàn)槭菑?fù)合模生產(chǎn)，所以采用下出件比較便于操作與提高生產(chǎn)效率。 3.4 導(dǎo)向方式的選擇 在沖壓過(guò)程中，導(dǎo)向結(jié)構(gòu)一般情況下直接與模架聯(lián)系在一起，該模具采用后側(cè)導(dǎo)柱的導(dǎo)向方式，提高模具壽命和工件質(zhì)量，方便安裝調(diào)整，故該復(fù)合模采用后側(cè)導(dǎo)柱的導(dǎo)向方式。 4 凸模、凹模、凸凹模的結(jié)構(gòu)設(shè)計(jì) 4.1 凸模結(jié)構(gòu)的設(shè)計(jì) 沖孔的圓形凸模，由于模具需要在凸模外面裝推件塊，因此設(shè)計(jì)成直柱的形狀，尺寸標(biāo)注如圖5。 圖5 圓形凸模 4.2 凹模結(jié)構(gòu)的設(shè)計(jì) 凹模的刃口形式，考慮到本例生產(chǎn)量大，所以采用刃口強(qiáng)度較高的凹模，即圖3所示的刃口形式。 凹模的外形尺寸，凹模的厚度（）和外徑分別為： 式中：式中：K——有b和材料厚度t決定的凹模厚度系數(shù)查表4.1 B——垂直于送料方向凹模型孔壁間最大距離 凹模壁厚c： 尺寸標(biāo)注如圖6所示。 表7 凹模厚度系數(shù) 圖6 凹模外形 4.3 凸凹模的的結(jié)構(gòu)設(shè)計(jì) 本模具為復(fù)合沖裁模，因此除沖孔凸模和落料凸模外，必然還有一個(gè)凸凹模。凸凹模的結(jié)構(gòu)圖如圖7所示。 校核凸凹模強(qiáng)度： 凸凹模的最小壁厚: 而實(shí)際最小壁厚為，故符合強(qiáng)度要求。凸凹模的外刃口尺寸按凹模尺寸配制，并保證雙面間隙。凸凹模上孔中心與邊緣距離尺寸的公差，應(yīng)比零件圖標(biāo)注精度高級(jí)，即定為。 圖7 凸凹模 5 模具材料的選用和模架的選擇 5.1 模具材料的選用 ⑴ 冷沖模用鋼應(yīng)具有的力學(xué)性能： 1）應(yīng)具有較高的變形抗力； 2）應(yīng)具有較高的斷裂抗力； 3）應(yīng)具有較高的耐磨性及抗疲勞性能； 4）應(yīng)具有較高的冷熱加工工藝性。 ⑵ 冷沖模零件材料選用原則： 1）要選擇能滿(mǎn)足模具工作要求的最佳綜合性能的材料； 2）要針對(duì)模具失效形式選用鋼材； 3）要根據(jù)制品的批量大小，以最低成本的選材原則選材； 4）要根據(jù)沖模零件的作用選擇材料； 5）要根據(jù)沖模精度程度選擇鋼材。 綜合各種材料進(jìn)行比較及材料的用途查下列表5.1和5.2可選擇為冷沖模工作零件所用的鋼材。 表8 冷沖模工作零件材料 零件名稱(chēng) 使用條件 選用材料 凸模，凹模，凸凹模，凸、凹模鑲塊，連續(xù)模，側(cè)刃凸模 形狀簡(jiǎn)單，沖裁材料厚度t小于等于3mm，中小批量生產(chǎn)的沖裁 T8、T8A、T10、T10A 沖裁件厚度t3mm，形狀復(fù)雜，或沖裁厚度t＞3mm的中小批量沖裁 Gr12、GrWMn、GGr15、Gr12MoV 要求批量較大，使用壽命較長(zhǎng)的沖裁模 W18Gr4V、Gr4W2MoV、W6Mo5GrV2、YG15、YG20 需要加熱沖裁模 3Gr2W8V、5GrNiMo、6Gr4Mo3NiWV 選擇說(shuō)明：在選擇沖裁凸模、凹模材料時(shí)，應(yīng)根據(jù)模具的工作條件和失效特點(diǎn)，量材而用。如形狀簡(jiǎn)單、尺寸較小、受力較小的凸、凹模，只需要熱處理工藝適當(dāng)。性能可以滿(mǎn)足使用，生產(chǎn)批量不大時(shí)，可選用碳素工具鋼，這樣可以降低成本；反之，就應(yīng)該選用變形較小，耐磨性高的合金工具鋼。對(duì)于大、中型沖裁模，其材料成本與模具總成本10%~18%左右，故應(yīng)選用變形小、耐磨性高的合金工具鋼較適宜。 表9 冷沖模輔助材料的選用 零件名稱(chēng) 選用材料 熱處理 硬度HRC 上模座、下模座 HT20~40HT25~47、ZG25、ZG35A3、A5 模柄 A3、A5 凸模固定板、凸、凹模固定板 A3、A5 側(cè)面導(dǎo)板 45 淬火 43~48 導(dǎo)柱 20 滲碳0.8~1 58~62 導(dǎo)套 20 淬火 58~60 導(dǎo)正銷(xiāo)、定位銷(xiāo) T7、T8 淬火 52~56 擋料銷(xiāo)、擋料板 45 淬火 45~48 墊板、定位板 45、T7A 淬火 43~48 螺母、墊圈 A3 固定螺栓、螺釘 A3、45 銷(xiāo)釘 45 淬火 45~48 頂桿、摧桿 45 淬火 43~48 5.2 模架的選擇 模架選用中等精度的中，小尺寸沖壓件的后側(cè)導(dǎo)柱模架，從右向送料，操作方便． 上模座： 下模座： 導(dǎo)柱： 導(dǎo)套： 墊板厚度： 凸模固定板厚度： 卸料板厚度?。? 彈簧外露高度： 模具閉合高度： 可見(jiàn)該模具閉合高度小于所選壓力機(jī)J23-40的最大裝模高度，由此可見(jiàn)，可以使用。 6 主要零部件的設(shè)計(jì) 6.1 定位零件的設(shè)計(jì) 落料凸模下部設(shè)置兩個(gè)導(dǎo)正銷(xiāo)，分別借用工件上和兩個(gè)孔作導(dǎo)正孔。導(dǎo)正孔的導(dǎo)正銷(xiāo)的結(jié)構(gòu)。導(dǎo)正應(yīng)在卸料板壓緊板料之前完成導(dǎo)正，考慮料厚和裝配后卸料板下平面超出凸凹模斷面1mm，所以導(dǎo)正銷(xiāo)直線(xiàn)部分的長(zhǎng)度為1.8mm。導(dǎo)正銷(xiāo)采用H7/h6配和。起粗定距的活動(dòng)擋料銷(xiāo)、彈簧和螺塞選用標(biāo)準(zhǔn)件，規(guī)格為8×16。 圖8 導(dǎo)正銷(xiāo) 6.2 導(dǎo)料板的設(shè)計(jì) 導(dǎo)料板的內(nèi)側(cè)與條料接觸，外側(cè)與凹模齊平，導(dǎo)料板與條料之間的間隙取1mm，這樣就可確定兩導(dǎo)料板的寬度，導(dǎo)料板的厚度按表選擇。導(dǎo)料板采用45鋼制作，熱處理硬度為40～45HRC，用螺釘和銷(xiāo)釘固定在凹模上。導(dǎo)料板的進(jìn)料端安裝有承料板。 6.3 卸料部件的設(shè)計(jì) [1]卸料部件的設(shè)計(jì) 卸料板的周界尺寸與凹模的周界尺寸相同，厚度為14mm。 卸料板采用45鋼制造，淬火硬度為40～45HRC. [2]螺釘?shù)倪x用 卸料板上設(shè)置4個(gè)卸料螺釘。公稱(chēng)直徑為12mm,螺紋部分為M10×10mm。卸 料釘尾部應(yīng)留有足夠的行程空間。卸料螺釘擰緊后，應(yīng)使卸料板超出凸模斷面1mm,有誤差時(shí)通過(guò)在螺釘與卸料板之間安裝墊片來(lái)調(diào)整。 7 模具總裝圖 該復(fù)合沖裁模將凹模即小凸模裝在上模上，是典型的倒裝結(jié)構(gòu)，圖9所示為本例的模具總圖。 模具上模部分主要由上模板、墊片、凸模、凸模固定板及卸料板等組成。卸料方式采用彈性卸料，以彈簧為彈性元件。下模部分由下模座、凹模板、導(dǎo)料板等組成。沖孔的廢料可通過(guò)凸凹模的內(nèi)孔從沖床臺(tái)面孔漏下。兩個(gè)導(dǎo)正銷(xiāo)控制條料送進(jìn)的導(dǎo)向，固定擋料銷(xiāo)控制送料的進(jìn)距。卸料采用彈性卸料裝置，彈性卸料裝置由卸料板、卸料螺釘、彈簧組成。沖制的工件由推件桿推簡(jiǎn)辦推銷(xiāo)和推件塊組成的剛性推件裝置推出。 條料送經(jīng)時(shí)采用活動(dòng)擋料銷(xiāo)作為粗定距，在落料凸模上安裝兩個(gè)導(dǎo)正銷(xiāo)利用條料上和孔作導(dǎo)正銷(xiāo)孔進(jìn)行導(dǎo)正，以此作為條料送進(jìn)的精確定距。操作時(shí)完成第一步?jīng)_壓后，把條料抬起向前移動(dòng)，用落料孔套在活動(dòng)擋料銷(xiāo)上，并向前推緊，沖壓時(shí)凸模上的導(dǎo)正銷(xiāo)再作精確定距?；顒?dòng)擋料銷(xiāo)位置電話(huà)設(shè)定比理想的幾何位置向前偏移0.2mm，沖壓過(guò)程中粗定位完成后，當(dāng)導(dǎo)正銷(xiāo)作精確定位時(shí)，由導(dǎo)正銷(xiāo)上圓錐形斜面再將條料向后拉回約0.2mm而完成精確定距，用這種方法定距，精確可達(dá)到0.02mm。 9 裝配圖 8 沖壓設(shè)備的選擇 通過(guò)校核，選擇開(kāi)式雙柱可傾壓力機(jī)能滿(mǎn)足使用要求。其主要技術(shù)參數(shù)如下： 公稱(chēng)壓力： 滑塊行程： 最大閉合高度： 連桿調(diào)節(jié)量： 工作臺(tái)尺寸： 墊板尺寸： 模柄孔尺寸： 最大傾斜角度： 9 模具的裝配和工作過(guò)程 9.1 模具的裝配 根據(jù)復(fù)合模裝配要點(diǎn)，選凹模作為裝配基準(zhǔn)件，先裝下模，再裝上模，并調(diào)整間隙、試沖、返修，具體裝配見(jiàn)表11。 表11墊板復(fù)合模的裝配 序號(hào) 工序 工藝說(shuō)明 1 凸、凹模預(yù)配 （1）裝配前仔細(xì)檢查各凸模形狀以及凹模形孔，是否符合圖紙要求尺寸精度、形狀。 （2）將各凸模分別與相應(yīng)的凹?？紫嗯?，檢查其間隙是否加工均勻。不合適者應(yīng)重新修磨或更換。 2 凸模裝配 以凹模孔定位，將各凸模分別壓入凸模固定板7的形孔中，并擰緊牢固 3 裝配下模 （1） 在下模座上劃中心線(xiàn)，按中心預(yù)裝凹模、導(dǎo)料板； （2） 在下模座、導(dǎo)料上，用已加工好的凹模分別確定其螺孔位置，并分別鉆孔，攻絲 （3） 將下模座、導(dǎo)料板、凹模、活動(dòng)擋料銷(xiāo)、彈簧裝在一起，并用螺釘緊固，打入銷(xiāo)釘 4 裝配上模 （1） 在已裝好的下模上放等高墊鐵，再在凹模中放入0.12mm片，然后將凸模與固定板的組合裝入凹模； （2） 預(yù)裝上模座，劃出與凸模固定板相應(yīng)螺孔。銷(xiāo)孔位置并鉆絞螺孔、銷(xiāo)孔； （3） 用螺釘將固定板組合、墊板、上模座連接在一起，但不要擰緊； （4） 將卸料板套裝在已裝入固定板的凸模上，裝上橡膠和卸料螺釘，并調(diào)節(jié)橡膠的預(yù)壓量，使卸料板高出凸模下端約1mm； 復(fù)查凸、凹模間隙并調(diào)整合適后，緊固螺釘；安裝導(dǎo)正銷(xiāo)、承料板；切紙檢查，合適后打入銷(xiāo)釘。 5 試沖愈調(diào)整 裝機(jī)試沖并根據(jù)試沖結(jié)果作相應(yīng)調(diào)整 9.2 模具的工作過(guò)程 模具屬于復(fù)合模其工作過(guò)程一般是在一次沖裁過(guò)程中能夠完成所有的成形過(guò)程（沖孔與落料）。工作時(shí)，條料由卸料板上面送入，依靠導(dǎo)料銷(xiāo)和擋料銷(xiāo)來(lái)對(duì)條料進(jìn)行正確的定位，上模下行卸料板與推件塊壓緊板料，然后凸凹模完成沖孔工作，上模繼續(xù)下行，工件要推件塊的壓緊即而完成落料，上?；厣龝r(shí)，由卸料板及推件塊完成卸料。 結(jié) 論 隨著我國(guó)經(jīng)濟(jì)的發(fā)展，模具對(duì)于現(xiàn)代工業(yè)來(lái)說(shuō)是十分重要的，尤其是沖壓技術(shù)的應(yīng)用。在各個(gè)領(lǐng)域幾乎都要用到與人們的生活息息相關(guān)。 在此次設(shè)計(jì)過(guò)程中用到了很多以前上課時(shí)學(xué)的知識(shí)，尤其是老師上課教給我們的一些分析問(wèn)題、解決問(wèn)題的思想在這次項(xiàng)目中都得到了很好的印證。這段時(shí)間的磨練，特別是最后兩個(gè)月的時(shí)間，使我的意志品質(zhì)力，抗壓能力及耐力也都得到了不同程度的提升。 當(dāng)然通過(guò)這次畢業(yè)設(shè)計(jì)，也留給我了一些教訓(xùn)和遺憾。在這段時(shí)間的前一階段，由于沒(méi)有深刻認(rèn)識(shí)到畢業(yè)設(shè)計(jì)的復(fù)雜性和反復(fù)性，請(qǐng)各位老師批評(píng)指正。 致 謝 時(shí)間過(guò)的真快，轉(zhuǎn)眼間大學(xué)生活就要結(jié)束，這段令人難忘的時(shí)光將成為美好的回憶。心中有好感概，是不想離開(kāi)，是遺憾，但更多的感激，這三年來(lái)有那么多的同學(xué)和老師給我了極大的幫助和關(guān)懷，我在這三年中不僅學(xué)到了技能知識(shí)，還知道了做人的道理。 經(jīng)過(guò)幾周的精心查閱書(shū)籍和精心的設(shè)計(jì)，功夫不負(fù)有心人，我的設(shè)計(jì)終于弄完了。在這次的畢業(yè)設(shè)計(jì)中，承我的指導(dǎo)老師程洋的悉心教導(dǎo)，并得到其他幾位同學(xué)的關(guān)心和幫助。 為此，再次感謝我們的指導(dǎo)老師在百忙之中給予我們?cè)O(shè)計(jì)的精心指導(dǎo)和極大的幫助。同時(shí)，也感謝我們的這組的成員在這次設(shè)計(jì)中給予我的幫助！謝謝！ 參考文獻(xiàn) 參考文獻(xiàn) [1王芳.《冷沖壓模具設(shè)計(jì)指導(dǎo)》.機(jī)械工業(yè)出版社，2010.7 [2韓洪濤.《機(jī)械制造技術(shù)》北京：化學(xué)工業(yè)出版社，2003.7 [3]郭紀(jì)林.《塑料模具沖壓成型技術(shù)》. 北京:清華大學(xué)出版社，2009.8 [4]蔡希林.《AutoCAD2006》.北京:清華大學(xué)出版社，2006，3 [5]武友德.《模具設(shè)計(jì)與制造》.機(jī)械工業(yè)出版社，2009.1.1 [6]吳元徽 .《模具材料與熱處理》.大連理工大學(xué)出版社。2009.6 Annals of the CIRP Vol. 56/1/2007 -269- doi:10.1016/j.cirp.2007.05.062 Design of Hot Stamping Tools with Cooling System H. Hoffmann 1 (2), H. So 1 , H. Steinbeiss 1 1 Institute of Metal Forming and Casting, Technische Universitt Mnchen, Garching, Germany Abstract Hot stamping with high strength steel is becoming more popular in automotive industry. In hot stamping, blanks are hot formed and press hardened in a water-cooled tool to achieve high strength. Hence, design of the tool with necessary cooling significantly influences the final properties of the blank and the process time. In this paper a new method based on systematic optimization to design cooling ducts in tool is introduced. The optimization procedure was coupled with FE analysis and a specific evolutionary algorithm. Through this procedure each tool component was separately optimized. Subsequently, the hot stamping process was simulated both thermally and thermo-mechanically with the combination of optimized solutions. Keywords: Hot Stamping, Finite element method (FEM), Optimization 1 INTRODUCTION In recent years, weight reduction while maintaining safety standards has been strongly emphasized in the automotive industry for building new models. Hot stamping of high strength steels for automotive inner body panels offers the possibility of fuel saving by weight reduction and enhances passenger safety due to its higher strength. In order to achieve high strength by hot stamping with high strength steels, blanks should be heated above austenitic temperature and then cooled rapidly such that the martensitic transformation will occur. Normally, the tools are heated up to 200C without active cooling systems in serial production 1. However, in hot forming processes, the tool temperature must maintain below 200C to achieve high strength. So far, very few studies have been conducted regarding the design of cooling systems in a hot stamping tool. This paper presents a systematic method to design hot stamping tools with cooling systems in optimal and fast manners, in which the cooling system is optimized with the help of FE analysis and a specific evolutionary algorithm. Subsequently, a series of hot forming processes was simulated thermally as well as thermo-mechanically to observe the heat transfer and the cooling rate through the optimized cooling system. In the hot stamping process the tool motion requires relatively short time compared to the whole process time. Therefore, thermal analysis of a series of hot stamping processes without considering the tool motion could be sufficient with reasonable accuracy and shorter computation time for quick design of the hot stamping tools with cooling system. However, thermo- mechanical analyses that include the motion of the punch and the forming process are necessary to enhance the accuracy of the predictions. In this paper, a crash relevant hot stamped component of a vehicle and its corresponding prototype of hot stamping tool are introduced in chapter 2. And the optimization procedure with FE analysis and evolutionary algorithm is introduced in chapter 3. Subsequently, the results of thermal and thermo-mechanical analyses with the optimized hot stamping tool are presented. 2 COOLING OF HOT STAMPING TOOL 2.1 Motivation To enhance the economical production procedure and good characteristics of the formed parts, hot stamping tools need to be designed optimally. Therefore, the main objective of this study is the optimal designing of an economical cooling system in hot stamping tools to obtain efficient cooling rate in the tool. So far, very few researches have been conducted regarding the design of cooling systems in hot stamping tools. Therefore, an advanced design method is required. Also, an adequate simulation model is required to perform the optimization and investigation of tools and products as fast and accurate as possible. 2.2 Characteristics of 22MnB5 In direct hot forming process, the quenchable boron- manganese alloyed steel 22MnB5 is commonly used. Also, 22MnB5 is one of the representative materials of ultra high strength steels. Therefore, in this study, aluminium pre-coated 22MnB5 sheet (Arcelors USIBOR) was considered as the blank material. The material 22MnB5 has a tensile strength of 600MPa approximately at the delivery state, and the tensile strength can be significantly increased by hot stamping process. Higher tensile strength is achieved in the hot stamping process by a rapid cooling at least at the rate of 27C/s 2. The initial sheet of 22MnB5 consisting of ferritic-perlitic microstructure must be austenitized before forming process in order to achieve a ductility of blank sheet. As the austenite cools very fast during quenching process martensite transformation will occur. This microstructure with martensite provides the hardened final product with a high tensile strength up to 1500 MPa. 2.3 Tool component and test part The components of the prototype hot stamping tool and its kinematics are shown in Figure 1 and the initial blank and the proposed test part in Figure 2. The initial blank has the dimension of 170mm x 430mm x 1.75mm and the draw depth of the proposed test part is 30mm. -270- faceplate counter punch blank holder punch faceplate table table blank distance bolts die barells plunger Figure 1: Schematic of a test hot stamping tool. Initial thickness: 1.75mm 4 3 0 m m1 7 0 m m 4 0 0 m m 1 0 0 m m Draw depth: 30mm Figure 2: Initial blank and drawn part. 2.4 Cooling systems in stamping tools The tool must be designed to cool efficiently in order to achieve maximum cooling rate and homogeneous temperature distribution of the hot stamped part. Hence, a cooling system needs to be integrated into the tools. The cooling system with cooling ducts near to the tool contour is currently well known as an efficient solution. However, the geometry of cooling ducts is restricted due to constraints in drilling and also the ducts should be placed as near as possible for efficient cooling but sufficiently away form the tool contour to avoid any deformation in the tool during the hot forming process. To guarantee good characteristics of the drawn part, the whole active parts of the tool (punch, die, blank holder and counter punch) need to be designed to cool sufficiently. 3 DESIGNING OF COOLING SYSTEMS 3.1 Optimization with Evolutionary Algorithm x s a boring position minimum distance between loaded contour and cooling duct (x) between unloaded contour and cooling duct (a) between cooling ducts (s) loaded contour unloaded contour coolant bore Constraints sealing plug input parameters of cooling system number of cooling channels and coolant bores diameter of cooling duct evaluation criteria cooling intensity and uniform cooling Optimization (Evolutionary Algorithm) 1 solution per given input separate optimization Solution Figure 3: Optimization procedure for each tool. The optimization procedure for design of a cooling system is presented in Figure 3. In this procedure, cooling channels can be optimized in each tool by a specific Evolutionary Algorithm (EA), which was developed at ISF (Institut fr Spannende Fertigung, Universitt Dortmund, Germany) for the optimization of injection molding tools and adapted for design of cooling systems in hot stamping tools 3,4. As constraints for optimization, the available sizes of connectors and plugs, the minimum wall thicknesses as well as the nonintersection of drill holes were considered. The admissible minimal distance between cooling duct and unloaded/loaded tool contour (a/x) and the minimal distance between cooling ducts (s) were determined through FE analyses. Parameters of the cooling system such as the number of channels (a chain of sequential drill holes), drill holes per channel and the diameter of the holes for each tool component were also provided as input parameters to the optimization. These input parameters can be obtained from existing design guidelines or through FE simulations. Based on the input parameters initial solution is generated randomly by EA or manually by the user. From the initial solution, the EA generates new solutions by recombination of current solutions and modifying them randomly. The defined constraints were subsequently used for the correction of the generated solutions and the elimination of inadmissible solutions. All the generated solutions were evaluated by optimum criteria such as efficient cooling rate and uniform cooling. Finally, the best solution was selected as optimized cooling channels for a selected tool component. 3.2 Optimized cooling channels In our research, the selected diameters of ducts were 8mm and 12mm for punch, 8mm, 12mm and 16mm for die, 8mm and 10mm for counter punch and 8mm for blank holder. EA was used to place the cooling channels optimally according to the given input and constraints for each tool component. The optimized profiles of the channels for duct diameter of 8mm are shown in Figure 4. c a b 4 0 0 m m 100mm 145 mm pu n c h cou n ter p un ch die b l an k h o ld er a b a b c a b 5 1 0 m m 260 mm a b c 70mm 510mm ab 260 mm a 110mm cooling medium plug 380mm a 70mm 250 mm b c b direction of cut view Figure 4: Optimized cooling channels with 8mm duct diameter. 4 EVALUATION OF THE OPTIMUM COOLING CHANNEL DESIGNS The design of cooling channels was generated by EA for each tool component with different bore diameters and their cooling performances were evaluated by using FE simulations. 4.1 Thermal analysis In the design and development phase of hot stamping tools, it is important to estimate the hot stamping process qualitatively and quantitatively within a short time for -271- economic manufacturing of tools. For this purpose, two transient thermal simulations were carried out with ABAQUS/standard, which uses an implicit method. In this analysis steel 1.2379 was selected as a tool material. The simulation model comprises 4 tool components: punch, die, blank holder and counter punch. In Table 1, the selected combinations of tool components with optimized cooling channels are presented. The variant V1 is the combination of optimized tools with small cooling duct diameters, whereas variant V2 with large cooling duct diameters. V1 V2 punch counter punch blank holder 8mm 8mm 8mm 8mm 12mm 10mm 16mm 8mm diameter of cooling duct die Table 1: Combinations of designed tools for FE analysis. In order to represent a series of production processes, a number of cycles of the hot stamping processes were simulated as a cycle heat transfer analysis. The Figure 5 shows the FE model including boundary conditions. cooling duct (c) T c = 20C h c = 4700W/m 2 C tool (t) T t,0 = 20C environment (e) T e = 20C h e = 3.6W/m 2 C counter punch blank holder punch blank die blank (b) T b,0 = 850C blank - tool D c = f (d,P) Figure 5: FE model and boundary conditions. This hot forming process for the prototype part was designed such that the cycle time is 30 sec. In a cycle, the punch movement for forming requires 3 sec, the tool is closed for 17 sec for quenching the blank and it takes another 10 sec for opening the tool and locating the next blank on the tool. However, in this thermal analysis, the tool motion and deformation of the blank was not considered to reduce the computation time. Hence, only heat transfer analysis was performed in a closed tool. In thermal analysis, the quenching process takes places 20 sec instead of 17 sec, because the motion of punch was not considered. It was assumed that the blank has an initial homogeneous temperature (T b,0 ) of 850C due to free cooling from 950C during the transfer in environment. The initial tool temperature (T t,0 ) was assumed as 20C at the first cycle and changes from cycle to cycle. The temperature of the cooling medium (T c ) was assumed as room temperature. Beside the boundary conditions, the required material properties of 22MnB5 were obtained from hot tensile test conducted at LFT (Lehrstuhl fr Fertigungstechnologie, Universitt Erlangen-Nrnberg, Germany), with whom a joint research on hot stamping is being conducted 2. In this analysis, convection from blank and tools to the environment (h e ), conduction within each tool, convection from tool into cooling channels (h c ) and heat transfer from hot blank to tool (D c ) were considered. Here, D c , is the contact heat transfer coefficient (CHTC) which describes the amount of heat flux from blank into tools. This coefficient usually depends on the gap d between tool and blank and the contact pressure P. It increases usually as the contact pressure increases. However, in thermal analysis the pressure dependent CHTC was not available, but a gap dependent coefficient was used. CHTC was assumed as 5000W/m 2 C at zero distance between blank and tool (gap) and keeps constant until the gap increases beyond critical value. 4.2 Thermo-mechanical analysis Simulation of hot forming is different from conventional sheet metal forming simulation, in which the distribution of temperatures or stresses in tools is neglected. For fast and easy way to analyze the hot forming process the tool and the blank were modelled with shell elements as in other studies 5,6. In these studies, the temperatures could be distributed along the thickness of the shell element with the user-defined function of temperature, but the temperature within the tool was not considered. Also, in this simulation model the heating of tools in a series of hot stamping processes were not considered. Furthermore, the shell model for thermal contact problems is just adequate for relatively short contact time 6. Therefore, in our studies the tools and the blank were modelled with volume elements to simulate the sequential heat transfer in a series of processes. The thermo- mechanical simulation was conducted with ABAQUS/explicit. In comparison to the thermal analysis, the whole forming and quenching process were modelled and the dynamic temperature and stress responses of tools in contact with hot blank were simulated by using time-temperature dependent flow stress curves. The heat transfer could be more accurately expressed using pressure dependent CHTC at contact places which change during forming process. In addition, temperature dependent thermal conductivity and specific heat were also considered. However, in thermo-mechanical analysis, as the number of elements increases, the complexity of the FE problem significantly increases. In conventional forming simulation an adaptive mesh can be normally used to spare the simulation time and to obtain a more accurate solution in the contact area. However, adaptive mesh refinement causes instability during computation in thermo- mechanical analysis. Therefore, a refined mesh with higher punch velocity was considered to reduce the simulation time. The heat transfer coefficients were scaled accordingly to obtain the same heat flux 7. 5 SIMULATION RESULTS AND DISCUSSION 5.1 Thermal analysis Figure 6 shows the temperature changes in the tool components for 10 cycles at tool combination V1 and V2. T C 400 300 100 0 030100 0 300100 die punch t s t s V1 V2 Figure 6: Temperature changes in heat transfer analysis. The results show that the hottest temperatures of the tools at the end of each cycle do not change almost after some cycles. The obtained cooling rates of the blank at the hottest point from 850C to 170C are 40C/s with V1 and 33C/s with V2 at 10th cycle and these are greater than the required minimum cooling rate of 27C/s. Furthermore, V1 leads to a more efficient cooling performance than V2. Better cooling performance for V1 compared to V2 can be explained with the geometric restrictions and the minimal wall thickness. A cooling duct with small diameter can be placed closer to the tool surface in a convex area and the amount of the cooling channels can be increased additionally. Usually, the heat dissipation in the convex area is slower than in concave area 6. The result shows also that the temperature of convex area in the punch -272- cools down slower than the concave areas in the die. Due to this fact, it can be concluded that the efficient cooling is most desired at convex area. 5.2 Thermo-mechanical analysis The heat transfer with optimized tool components was simulated thermally at first. However, there was a simplification of a hot stamping process in thermal analysis. Therefore, a thermo-mechanical analysis for V1 was performed to observe the differences and the significance of modelling the punch movement. Temperature change curves at the hottest point from the end of the first cycle in the blank, die and punch are shown in Figure 7. The tool cooled further 10 sec after quenching and the temperature changes in the die and punch were presented for 30 sec. A coupled thermo- mechanical analysis was done using gap-pressure dependent CHTC. The results from thermal analysis shows a cooling rate of 92C/s from 850C to 170C in comparison to 75C/s from thermo-mechanical analysis. 400 300 100 0 die punch 05 20 1000 800 400 T C 200 Thermal analysis Thermo-mechanical analysis t s 15 blank 0 0 5 30 0 5 25 30t s10 202510 20t s T C Figure 7: Temperature changes in thermal and thermo- mechanical analysis (1th cycle). To verify the accuracy of a thermal analysis or to predict a serial production process more accurately a series of thermo-mechanical analysis was done. For this analysis the punch velocity was increased 10 times and 10 hot stamping processes were simulated. In Figure 8, the temperature change curves at the hottest point of the die and punch from a thermal and thermo-mechanical analysis are compared for 10 cycles. Finally, the temperature distributions in the blank at the end of the 10th cycle are shown in Figure 9. 400 300 100 0 TC 030ts100 030ts100 die punch thermal thermo-mechanical Figure 8: Temperature changes for 10 cycles. (b) T C (a) 130 60 102 74 88 116 T C 140 70 112 84 98 126 Figure 9: Temperature fields of blanks at the end of 10th cycle: (a) thermal and (b) thermo-mechanical analysis. In Figure 8, the temperature differences at the end of 10th cycle between the thermal and thermo-mechanical analyses were 7C in the die and 3C in the punch. Subsequently, the Figure 9 indicates that the maximum temperature of the blank from the thermal analysis is slightly greater than that of the thermo-mechanical about 10C. Nonetheless, the temperature fields of blanks from both analyses are very similar. As a consequence, the thermal analysis for a series of hot stamping processes is relatively accurate compared to the thermo-mechanical analysis. Furthermore, a thermal heat transfer analysis could be used to design and develop the hot stamping tools in the early phase due to its timesaving computation. 6 CONCLUSION AND FUTURE WORK A systematic method has been developed for optimizing the geometrical design of the cooling systems of hot stamping tools. This methodology was successfully applied to design of cooling channels in a prototype tool for efficient cooling performance. This indicates that the method can be used for designing cooling systems in other stamping tools as well. This paper presented both thermal and thermo- mechanical simulations to represent a series of hot stamping processes. The thermal analysis could be used for an optimization and investigation of hot stamping processes especially in the developing stage. However, a thermo-mechanical analysis is needed to predict more accurately but it is still time consuming to analyze the processes within adequate time period. To resolve this problem, an alternative simulation model will be further studied. Also, a more accurate contact condition for thermo-mechanical analysis remains to be studied. To validate this proposed method and its corresponding FE model, a prototype tool is currently being built and experiments will be carried out for validation. 7 ACKNOWLEDGMENTS We extend our sincere thanks to all joint project researchers of LFT and ISF. 8 REFERENCES 1 Sik