ZL50裝載機(jī)總體及工作裝置設(shè)計(jì)
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鎮(zhèn) 江 高 專
ZHENJIANG GAOZHUAN
畢 業(yè) 設(shè) 計(jì) (論 文)
冷沖壓設(shè)計(jì)—彎曲沖孔落料連續(xù)模
Cold Stamping Design-bending modulus material Pierce
系 名： 機(jī)械工程系
專業(yè)班級：計(jì)算機(jī)輔助設(shè)計(jì)與制造（CAD）
學(xué)生姓名： 章麗黎
學(xué) 號(hào)： 04012117
指導(dǎo)教師姓名： 劉波
指導(dǎo)教師職稱： 講師
2007年 3 月
目錄
引言
一.設(shè)計(jì)說明書………………………………………………………………………1
1.工藝分析………………………………………………………………………5
2.工藝方案確定…………………………………………………………………5
3.模具結(jié)構(gòu)形式的確立…………………………………………………………6
4.工藝分析………………………………………………………………………6
(1) 計(jì)算毛坯尺寸………………………………………………………………6
(2) 排樣圖………………………………………………………………………7
(3) 材料利用率…………………………………………………………………8
(4) 計(jì)算沖壓力…………………………………………………………………8
(5) 壓力機(jī)選定…………………………………………………………………9
(6) 壓力中心計(jì)算………………………………………………………………9
(7) 凸凹模計(jì)算…………………………………………………………………10
(8) 凹模各孔口位置尺寸………………………………………………………11
(9) 卸料板各孔尺寸………………………………………………………………12
5.填寫沖壓工藝卡………………………………………………………………12
6.模具結(jié)構(gòu)設(shè)計(jì)…………………………………………………………………12
7.畫裝配于和零件圖
8.校核壓力機(jī)安裝尺寸
9.編寫技術(shù)文件…………………………………………………………………13
結(jié)論…………………………………………………………………………………13
致謝…………………………………………………………………………………13
參考文獻(xiàn)……………………………………………………………………………13
冷沖壓(彎曲零件)
專業(yè)班級：計(jì)算機(jī)輔助設(shè)計(jì)與制造(CAD)學(xué)生姓名：章麗黎
指導(dǎo)教師：劉波 職稱：講師
摘要: 本設(shè)計(jì)完成的是冷沖壓彎曲零件，使典型的沖孔彎曲落料連續(xù)模具。材料為45鋼，料厚1.3mm
模具工序主要包括沖孔，壓凸，彎曲及落料。
關(guān)鍵詞: 沖孔 彎曲
Abstract : The design is completed by bending parts cold stamping, bending down so typical of continuous punching die. 45 steel materials, material thickness of coated mold processes including punching, pressure convex, bending and blanking. Keywords : Bending Punch
引 言
模具是制造業(yè)的重要工藝基礎(chǔ)，在我國，模具制造屬于專用設(shè)備制造業(yè)。我國雖然很早就開始制造模具和使用模具，但長期未形成產(chǎn)業(yè)。直到20世紀(jì)80年代后期，我國模具工業(yè)才駛?cè)氚l(fā)展的快車道。近二十年來，模具產(chǎn)業(yè)的產(chǎn)值以每年15%的速度遞增。2000年我國模具工業(yè)的總產(chǎn)值達(dá)到280億元人民幣。在模具工業(yè)的總產(chǎn)值里，沖壓模具占到50%，塑料模具約占33%，壓鑄模具約占6%，其他各類模具約占11%。
冷沖壓工藝與其他加工相比，有以下特點(diǎn)：
1） 用冷沖壓可以得到形狀復(fù)雜、用其他加工方法難以加工的工件，如薄殼零件等。冷沖壓件的尺寸精度是由模具保證，因此，尺寸穩(wěn)定，互換性好。
2） 材料利用率高、工件重量輕、剛性好、強(qiáng)度高、沖壓過程耗能少。
3） 操作簡單，勞動(dòng)強(qiáng)度低、易于實(shí)現(xiàn)機(jī)械化和自動(dòng)化、生產(chǎn)效率高。
4） 沖壓加工所用的模具結(jié)構(gòu)一般比較復(fù)雜，生產(chǎn)周期較長、成本較高。
由于冷沖壓有許多的優(yōu)點(diǎn)，因此，在機(jī)械制造、電子、電器等各行各業(yè)中，都得到了廣泛的應(yīng)用。
這次設(shè)計(jì)中的冷沖壓彎曲件要求精度高，形狀復(fù)雜，要求表面平整，毛刺高度不得大于0.08mm。若采用鑄造工藝生產(chǎn)很難保證產(chǎn)品質(zhì)量，而且使用該工藝將消耗大量的能量，不利于節(jié)能降耗，需要增加環(huán)境保護(hù)上的投入，最終會(huì)增加企業(yè)的生產(chǎn)成本。若是采用冷沖壓工藝生產(chǎn)，這樣既有利于保證加工出來的產(chǎn)品能達(dá)到設(shè)計(jì)要求，又有利于保證生產(chǎn)的產(chǎn)品的有很高的一致性，方便日后維修更換。此外采用冷沖壓的工藝有利于進(jìn)一步降低勞動(dòng)者的勞動(dòng)強(qiáng)度，體現(xiàn)了“以人為本”的生產(chǎn)理念。再者采用冷沖壓的工藝可以提高材料的利用率，降低企業(yè)生產(chǎn)成本，并且節(jié)約了金屬材料。而且目前國際上沖壓生產(chǎn)成為生產(chǎn)優(yōu)質(zhì)機(jī)電產(chǎn)品的重要手段，采用冷沖壓工藝可以跟上先進(jìn)生產(chǎn)工藝的發(fā)展潮流，有利于提高企業(yè)的競爭力。
因此該冷沖壓彎曲件宜采用冷沖壓工藝生產(chǎn)，由于彎曲件的質(zhì)量要求高，故生產(chǎn)該冷沖壓彎曲件可以采用高精度的沖裁模生產(chǎn)。連續(xù)模沖壓在提高生產(chǎn)率、降低成本、提高質(zhì)量和實(shí)現(xiàn)沖壓自動(dòng)化方面有重要作用。在現(xiàn)代沖壓技術(shù)中，發(fā)展連續(xù)模占有重要地位。
制件如圖所示,材料為45鋼,料厚1.3mm,制件為大批量生產(chǎn)。
1. 工藝分析
該制件形狀簡單,尺寸中等,厚度適中,大批量生產(chǎn),屬于普通沖壓件,但應(yīng)注意:
1)5×R2mm的孔壁間距足夠,但 為了保證模具的壽命安全應(yīng)分開沖壓。
2)考慮制件取料,從安全方便采取適當(dāng)方法。
3)因大批量生產(chǎn),應(yīng)重視模具材料和結(jié)構(gòu)選擇,保證模具壽命。
2. 工藝方案的確定
根據(jù)制件工藝性分析,其基本工序有落料,沖孔,彎曲三種。按先后順序組合得五種方案,如下:
(1)落料—彎曲—沖孔--壓凸，單工序沖壓。
(2)落料—沖孔--壓凸—彎曲, 單工序沖壓。
(3)沖孔—壓凸--切口—彎曲—落料,單件復(fù)合沖壓。
(4)沖孔—壓凸--切口—彎曲—切斷--落料,兩件連沖復(fù)合。
(5)沖孔--壓凸--切口—彎曲—切斷,兩件連沖級進(jìn)沖壓。
方案1）2）屬于單工序沖壓。由于制件生產(chǎn)批量較大，尺寸一般，這兩種方案生產(chǎn)率低，操作也不安全，故不宜采用。
方案3）4）屬于復(fù)合式?jīng)_壓。由于制件較小，壁厚小，采用復(fù)合模裝配較困難，強(qiáng)度也會(huì)受影響，壽命不高。又因沖孔在前，落料在后，以凸模插入材料和凹模內(nèi)進(jìn)行落料，必然受到材料的切向流動(dòng)壓力，有可能使φ4mm凸?？v向變形，因此采用復(fù)合沖壓，除解決了操作安全性和生產(chǎn)率等問題外，又有了新難題，因此使用價(jià)值不高，也不宜采用。
方案5）屬于級進(jìn)沖壓，既解決了1）2）方案的問題，又不存在3）4）方案的難點(diǎn)，故為最合理的方案
模具結(jié)構(gòu)形式的確定
為方便操作和取件,選用雙柱可傾壓力機(jī),縱向送料。因制件彎曲要求精度高不移動(dòng),可采用有側(cè)刃定位,生產(chǎn)率高,材料消耗也不大。
3. 工藝設(shè)計(jì)
(1) 計(jì)算毛坯尺寸 相對彎曲半徑為
R/t=2/1.3=1.54>0.5
式中R---彎曲半徑(mm)
t----料厚(mm)
可見,制作屬于圓角半徑較大的彎曲件,應(yīng)先求中性層曲率半徑ρ(mm)由參考文獻(xiàn)[2]中心層位置計(jì)算公式
ρ=R+Xt
式中X---由實(shí)驗(yàn)測定的應(yīng)變中性層位移系數(shù)。
由參考文獻(xiàn)[1]表格5-5,查出X=0.36
ρ=R+Xt=(2+0.36×1.3)=2.468
由參考文獻(xiàn)[2]圓角半徑較大(R>0.5t)的彎曲件毛料長度計(jì)算公式,
L0=ΣL直+ΣL彎；L彎=2×(180°-α)πρ/ 180°
式中L0---彎曲毛料展開長度(mm)
ΣL直---彎曲件各直線段長度(mm)
ΣL彎---彎曲件各彎曲部分中性層展開長度總和(mm)
由(圖1)可知
L彎=2×(180°-α)πρ/ 180
=2×(180°-90°)×3.141592×2.468/180°
=7.75mm
L直=21+26.2+30.8-2×7.75=62.5mm
L0= L彎+L直=70.25mm≈71mm
(2)畫排樣圖
由文獻(xiàn)[2]表2-9,切斷工序中工藝廢料帶的標(biāo)準(zhǔn)值,表2-10,切口工序中工藝廢料的標(biāo)準(zhǔn)值。表2-13中廢料寬度公差△,表2-14,側(cè)刃裁切的條料的切口寬F,得F=1.5mm；S=3.5mm； △=0.7 mm；C=5mm
由文獻(xiàn)[2]采用側(cè)刃條料寬度尺寸B (mm)的確定公式
B=(2 L0+2F+1.5a+C)0-△ = (71×2+5+1.5×2+1.5×2 )0-0.7mm = 1530-0.7mm
步距 A=D+S=20+3.5=23.5mm
如圖所示,畫排樣圖
(3) 計(jì)算材料利用率η 由文獻(xiàn)[2]材料利用率通用計(jì)算公式
η=A0/A×100％
式中A0---得到制件的總面積(mm2)
A---一個(gè)步距的條料面積(L×B)(mm×mm)
得η=71×20×2/(23.5×153)=79%
(4) 計(jì)算沖壓力 完成制件所需的沖壓力由沖裁力、彎曲力及卸料力、推料力組成,不需計(jì)算彎曲時(shí)的頂料力和壓料力。
1) 沖裁力 F沖---由沖孔力、切口力、切斷力和側(cè)刃沖壓力四部分組成。
由文獻(xiàn)[1]沖裁力F(N)的計(jì)算公式
F沖=KLtτ0或F沖=Ltσb
式中K---系數(shù),K=1.3；
L---沖裁周邊長度(mm)
τ0---材料抗剪強(qiáng)度(Mpa)
σb---材料抗拉強(qiáng)度(Mpa)
由文獻(xiàn)[1]4-12得
σb=600Mpa
F沖=2×600×1.3[5×4×3.14+2(2.5+78)+3.14×7.85+2×7.95+2(22.5+1.5)]
=2×780[62.8+390+24.649+15.9+48]
=2×416129N=844504N=844.5KN
2) 壓凸力F凸
壓凸即平板毛坯的局部壓凹坑,由文獻(xiàn)[3]查得
F=ARt2
式中 A---成形面積(mm2)
R---系數(shù),鋼料R=200～300N/mm4
由(圖4)可知
F凸=ARt2=0.5×3.14×1.42×300×1.3×1.3
=1560.1N=1.6KN
3) 彎曲力F彎---45鋼可以采用自由彎曲力
由文獻(xiàn)[1]得,U形件彎曲力:
F彎=0.7Kbt2σb/(r+t)
式中F彎---沖壓結(jié)束時(shí)的自由彎曲力(N)
K---安全系數(shù),一般取K=1.3；
b---彎曲件寬度(mm)
r---彎曲件的內(nèi)彎曲半徑(mm)
F彎=2×0.7Kbt2σb/(r+t)=2×0.7×1.3×153×1.3×1.3×600/3.3
=2×42781.58N=85.6KN
4) 卸料力F卸和推料力F推
F卸=K卸F沖=0.06×844.5KN=50.7K
F推=K推F沖n=0.05×844.5KN=42.225KN
F=F沖+F凸+F彎+F卸+F推
=844.5+1.6+85.6+50.7+42.225
=1024.625KN≈1025KN
(5) 初選壓力機(jī),查文獻(xiàn)[3]表8-10開式雙柱可傾壓力機(jī)部分參數(shù)
選壓力機(jī)型號(hào)為J23-125
(6) 計(jì)算壓力中心,本模具圖形規(guī)則對稱,兩件對排,左右對稱,故采用解析法求壓力中心比較方便。建立坐標(biāo)系(如圖3)
因?yàn)樽笥覍ΨQ
所以XG=0,只需求YG.
根據(jù)合力矩定理有
YG= Y1F1+Y2F 2+ Y3F3+ Y4F4 +Y5F5+ Y6F6+ Y7F7+ Y8F8+ Y9F9+ Y10F10+ Y11F11
=2×[10×4×3.14+15.2×4×3.14+4.8×4×3.14+10(7.85×3.14+2×7.95)
+11.75×(6+23.5)+33.5×4×3.14+33.5×2.8×3.14+68.75(3.5+2×71)
+ 104×(2×20+2×28.2)]+129.25×(2×5+2×23.5)
=51834.05/824≈63mm
(7) 計(jì)算凸凹刃口尺寸 本制件采用單配法加工刃口,這樣加工的尺寸更精確。
該制件以沖孔落料為主,只要計(jì)算落料凹模尺寸及制造公差,由文獻(xiàn)[1]表3-3查得,Zmin=0.132mm Zmax=0.180mm
采用單配法加工凹凸模尺寸，根據(jù)文獻(xiàn)[3]表2-14，具體模具具體配制
1)沖孔凸模1
工件尺寸:直徑為φ4mm的圓, 文獻(xiàn)[3]表2-15得△=0.10mm
查文獻(xiàn)[3]表2-13得X=0.75
根據(jù)文獻(xiàn)[3]表2-14,Bp=(B+X△)-0.25δ。
則 BP=(4+0.75×0.10)0-0.25△=4.0750-0.025mm
2)沖孔凸模2
工件尺寸:長邊:7.95mm, 短邊：φ7.85mm
查文獻(xiàn)[3]表2-13得X=0.75；△=0.09mm
則 BP1=（7.95+0.75×0.09）0-0.25△=8.010-0.0225
BP2=（7.85+0.75×0.09）0-0.25△=7.910-0.0225
3）壓凸凸模
工件尺寸：φ1.2mm和φ2.8mm的圓
查文獻(xiàn)[3]表2-13得X=0.75；根據(jù)表2-15,查到△=0.1mm
則 BP1=(1.2+0.75×0.10) 0-0.25△=1.280-0.025mm
BP2=(2.8+0.75×0.10) 0-0.25△=2.880-0.025mm
凸模8安裝在凹模板上
4) 切口凸模
工件尺寸：長71mm寬3.5mm
根據(jù)文獻(xiàn)[3]表2-16,△=0.130mm；查表2-13得X=0.75
則 BP1=(71+0.75×0.130)0-0.25△=71.090-0.0325mm
BP2=(3.5+0.75×0.130) 0-0.25△=3.590-0.0325mm
5）彎曲模
工件尺寸：成型部分 長112mm，寬20mm，總體尺寸 長147mm,寬20mm
彎曲模相當(dāng)于落料模,以落凹模尺寸配制凸模
查文獻(xiàn)[3]表2-13得X=0.75；根據(jù)表2-16,查到公差分別為△=0.16mm
則成型部分
Ad1=(112-0.75×0.16) 0-0.25△=111.280-0.04mm
Ad2=(20-0.75×0.160) 0-0.25△=19.840-0.04mm
6）切口與切斷刃口尺寸:由于在切口與切斷工序中,凸凹模均只在三個(gè)方向與板料作用并使之分離,并由排樣圖可知,尺寸C和S既不是沖孔尺寸也不是落料尺寸,要正確控制C和S兩個(gè)尺寸才能間接保證制件外形尺寸,為使方便計(jì)算,直接取C和S值為凸模基本尺寸,間隙取在凹模上。
切邊凸模
工件尺寸: 長23.5mm,寬10mm
根據(jù)文獻(xiàn)[3]表2-16,△=0.19mm；
則 BP1=100-0.048mm
BP2=23.50-0.048mm
切斷凸模
工件尺寸:長23.5mm寬5mm
查表文獻(xiàn)[3]2-16, △=0.13
則 Bp1=23.50-0.033 mm
Bp2=50-0.033 mm
7）側(cè)刃尺寸:側(cè)刃為標(biāo)準(zhǔn)件,根據(jù)送料步距和修邊值查側(cè)刃值表,按標(biāo)準(zhǔn)取側(cè)刃尺寸。
由文獻(xiàn)[2]表2-11側(cè)面切口尺寸得:
側(cè)刃寬度B=10mm 側(cè)刃長度L=23.5mm
(8) 凹模各孔口位置尺寸 本制件尺寸較多,包括兩側(cè)刃孔位置尺寸、5個(gè)小孔尺寸、槽形尺寸、兩切口?？孜恢眉扒袛嗫卓谖恢贸叽纭Ｆ浠境叽缈砂磁艠訄D確定其制造公差按文獻(xiàn)[2]表2-2沖裁件精度應(yīng)為IT12級。但本制件送進(jìn)工步較多,累積誤差過大,會(huì)造成凸凹模間隙不均,影響沖裁質(zhì)量和模具壽命,故應(yīng)將模具制造精度提高?？紤]到加工經(jīng)濟(jì)性,送料方向尺寸按IT11制造,其他位置按IT11∽IT12級制造,凸模固定板與凹模配制。尺寸參見(圖4)
(9)卸料板各孔尺寸 卸料板各型孔尺寸應(yīng)與凸模保持0.5Zmin間隙,這樣有利于保護(hù)凸凹模刃口不被啃傷,根據(jù)此原則確定具體尺寸,如(圖10)
⒌模具結(jié)構(gòu)設(shè)計(jì)
(1) 凹模設(shè)計(jì) 因制件形狀簡單,雖然六個(gè)工步,但制件有沖裁和彎曲兩種模。沖裁模采用Cr12MoV為凹模材料,而彎曲模也可采用同種材料。因?yàn)镃r12MoV具有高耐磨的作用。
1) 確定凹模厚度H值:由文獻(xiàn)[2]凹模厚度計(jì)算公式
H=3√F沖×10-1=3√84450≈43.874mm≈44mm
2)確定凹模周界尺寸L×B:由文獻(xiàn)[2]凹?？妆诤竦拇_定公式,
凹?？卓谳喞€為直線時(shí):W2=1.5H.由(圖5)和文獻(xiàn)[2]圖3-13得
W2=1.5H=1.5×44=66mm
L=280～290mm B=270～280mm
由文獻(xiàn)[4]表5-43矩形凹模標(biāo)準(zhǔn)可查到較為靠近的凹模周界尺寸為
315mm×250mm×45mm據(jù)此值查文獻(xiàn)[4]表5-2,可得典型組合315×250×215～250mm
而由此典型組合標(biāo)準(zhǔn),即可方便地確定其他沖模零件的數(shù)量、尺寸及主要參數(shù)。
(2) 選擇模架及確定其他沖模零件尺寸 由凹模周界尺寸及模架閉合高度在215～250之
查文獻(xiàn)[4]表5-7選用對角標(biāo)記為315×250×215～250mmI并可根據(jù)此標(biāo)準(zhǔn)畫出標(biāo)準(zhǔn)模架圖.類似也可查出其他零件尺寸參數(shù),此時(shí)即可轉(zhuǎn)入畫裝配圖。
6.畫裝配圖和零件圖
7.校核壓力機(jī)安裝尺寸
模座外形尺寸為445mm×330mm,閉合高度為250mm,由文獻(xiàn)[3]表8-10,JB23-125型壓力機(jī)工作臺(tái)尺寸為710mm×1080mm,最大閉合高度為480mm,連桿調(diào)節(jié)長度為38故在工作臺(tái)上加一100mm墊板即可安裝.模柄孔尺寸也一致。
8.編寫技術(shù)文件
填寫沖模零件機(jī)械加工工藝過程卡。
結(jié) 論
通過畢業(yè)設(shè)計(jì)的準(zhǔn)備工作，使我進(jìn)一步提高了獨(dú)立調(diào)研能力以及專業(yè)業(yè)務(wù)素質(zhì)。并通過文獻(xiàn)查閱，現(xiàn)場收集資料等工作，鍛煉了解決模具專業(yè)工程技術(shù)問題的能力。鞏固深化擴(kuò)充了專業(yè)知識(shí)，并通過對畢業(yè)設(shè)計(jì)中涉及到的問題的研究，提出了自己的觀點(diǎn)，完成了設(shè)計(jì)任務(wù)。經(jīng)歷了一次嚴(yán)格的綜合的工程訓(xùn)練。
經(jīng)過將近2個(gè)月的畢業(yè)設(shè)計(jì)，使我把這三年所學(xué)的書本知識(shí)得到了全面運(yùn)用。在這2個(gè)月的時(shí)間里，我們集體到常州戚墅堰機(jī)車車輛廠進(jìn)行了參觀了解，然后在老師的指導(dǎo)下，我們認(rèn)真的查閱了有關(guān)的資料書籍，翻閱了以前的課本資料。在老師和同學(xué)的幫助下盡量把問題搞懂，搞清楚。
通過這次的畢業(yè)設(shè)計(jì)，使我對模具有了更深的了解。模具具有設(shè)計(jì)和制造周期短、投資少，生產(chǎn)率高，對工人的技術(shù)水平要求不高等優(yōu)點(diǎn)。這使得模具在現(xiàn)代機(jī)械制造工業(yè)中得到廣泛的運(yùn)用。
通過此設(shè)計(jì)，學(xué)會(huì)運(yùn)用標(biāo)準(zhǔn)，規(guī)范，手冊，圖冊有關(guān)技術(shù)資料等，培養(yǎng)模具的設(shè)計(jì)的基本技能。培養(yǎng)了我們的設(shè)計(jì)能力，獨(dú)立思考，嚴(yán)肅認(rèn)真，精益求精的基本技能。
2個(gè)多月的時(shí)間轉(zhuǎn)眼即過。但整個(gè)設(shè)計(jì)把我這三年的知識(shí)做了一次系統(tǒng)的復(fù)習(xí)和鞏固，也是理論和時(shí)間相結(jié)合的一次大的運(yùn)用過程，為我們即將走上工作崗位，走上社會(huì)提供了一次鍛煉的機(jī)會(huì)。在設(shè)計(jì)中，不免存在失誤之處，望老師給予批評，指正。
總之,這次畢業(yè)設(shè)計(jì)讓我收獲頗豐,不僅鍛煉了我的能力,也為以后踏上工作崗位奠定了良好的基礎(chǔ).因此,我很感謝學(xué)校在畢業(yè)前給我這么一次好的機(jī)會(huì)和所有輔助我的指導(dǎo)老師.
致 謝
光陰似箭，大學(xué)生活瞬間即逝。在做畢業(yè)設(shè)計(jì)的過程中，得到老師的耐心指導(dǎo)加上自己的不懈努力終于完成了畢業(yè)設(shè)計(jì)。在這次畢業(yè)設(shè)計(jì)中，將書本上所學(xué)到的相關(guān)的知識(shí)都運(yùn)用到設(shè)計(jì)里面，又一次的鞏固了所學(xué)內(nèi)容，。在完成這一設(shè)計(jì)的過程中，我遇到了許多困難。面對它們，我并沒有退縮，而是查資料、尋找各種幫助。在老師的指導(dǎo)和同學(xué)的幫助下，這些問題終于迎刃而解！在這里，對幫助自己完成這次畢業(yè)設(shè)計(jì)的同學(xué)表示真誠的謝意。在此特別感謝劉波老師以及三年來所有教過我的老師，沒有你們耐心的教導(dǎo)，自己不可能相有關(guān)知識(shí)與技能的積累也就不可能完成這次畢業(yè)設(shè)計(jì)。在兩個(gè)月的時(shí)間里劉波老師在百忙之中不斷的指導(dǎo)我、幫助我，使我通過這次畢業(yè)設(shè)計(jì)中拓寬了知識(shí)面完善了知識(shí)結(jié)構(gòu)，受益非淺！對于我不懂的問題，只要提出他就毫不吝嗇的、不厭其煩地幫我解決，劉波師這兩個(gè)月來付出了辛勤汗水，換來了我的這次設(shè)計(jì)！我會(huì)謹(jǐn)記老師的教誨，為社會(huì)貢獻(xiàn)一份自己的力量?？傊瑳]有你們的幫助，我很難完成這次設(shè)計(jì)，再一次表示我對你們最真誠的謝意。
參考文獻(xiàn)
[1]丁松聚.冷沖模設(shè)計(jì)
[2]趙孟棟.冷沖模設(shè)計(jì)
[3]王芳.冷沖壓模具設(shè)計(jì)指導(dǎo)
[4]史鐵梁.模具設(shè)計(jì)指導(dǎo)
16
大連交通大學(xué)2017屆本科生畢業(yè)設(shè)計(jì)外文翻譯
knowledge-based blackboard framework for stamping process planning in progressive die design
S.B. Tor · G.A. Britton · W.Y. Zhang
Springer-Verlag London Limited 2004
Abstract： It is widely accepted that stamping process planning for the strip layout is a key task in progressive die design. How-ever, stamping process planning is more of an art rather than a science. This is in spite of recent advances in the field of artificial intelligence, which have achieved a lot of success in incorporating built-in intelligence and applying diverse know-ledge to solving this kind of problem. The main difficulty is that existing knowledge-based expert systems for stamping process planning lack a proper architecture for organizing heterogeneous knowledge sources (KSs) in a cooperative decision making en-vironment. This paper presents a knowledge-based blackboard framework for stamping process planning. The proposed ap-proach speeds up the progressive die design process by automat-ing the strip layout design. An example is included to show the effectiveness of the proposed approach.
Keywords ：Knowledge-based · Object-oriented · Progressive die design · Stamping process planning
1.Introduction
Progressive dies for producing sheet metal parts in mass pro-duction have been widely applied in various industries such as aerospace, electronics, machine tools, automobiles, and re-frigeration. These dies can perform piercing, notching, cut-off, blanking, lancing, bending, shaving, drawing, embossing, coin-ing, trimming, and other miscellaneous forming operations at a single setup. Hence, a progressive die is generally very com-plex. Stamping process planning and die structure design are difficult and demanding tasks.
Stamping process planning starts with an unfolding of a model of stamped metal part to produce a flat pattern, followed by nesting the pattern to produce a blank layout. Next, stamping operations are planned and operations are assigned to die sta-tions. The resulting plan is typically represented as a strip layout, which guides the subsequent die structure design. The produc-tivity, accuracy, cost, and quality of a progressive die mainly depends on the strip layout, and hence a stamping process. How-ever, stamping process planning still remains more of an art rather than a science. Historically, this activity is mainly car-ried out manually, based on designers’ trial-and-error experience, skill and knowledge.
Recent advances in the field of artificial intelligence (AI) have given rise to the possibility to construct AI-based systems that incorporate built-in intelligence and apply diverse knowledge to solving progressive die design problems, including strip layout design automation. The diverse knowledge sources (KSs) re-lated to stamping process planning include unfolding knowledge to produce a flat pattern, nesting knowledge to produce a blank layout, mapping knowledge to transform stamping features into stamping operations, and staging knowledge to sequence the stamping operations. A discussion of some knowledge-based pro-gressive die design work related to our study can be found in Sect. 2. However, the existing work is based on the conventional architecture of knowledge-based expert systems, which are in-capable of managing heterogeneous KSs effectively. This limits both their practicability and scalability.
To address the above issue, it is necessary to provide a coop-erative problem solving strategy that can foster communication between diverse KSs, and accommodate different knowledge representation schemes within an integrated framework. Hence, a knowledge-based blackboard framework consisting of a black- board control system and a few independently executing KSs have been developed. This framework provides a cooperative de-cision making environment and facilitates a hybrid knowledge representation scheme, including procedures, production rules, and object-oriented representations.
A prototype system has been implemented using the object-oriented expert system shell CLIPS (C Language Integrated Pro-duction System) [1], which is interfaced with a parametric- and feature-based CAD system, Solid Edge through C++. An ex-ample is provided to demonstrate our approach and to show its effectiveness in stamping process planning.
2.Related work
Research in the computer-aided stamping process planning has been widely reported since the 1970s. The advantages of auto-mated process planning are productivity improvements, cost re-ductions, and design automation.
From the mid 1970s to mid 1980s, the first generation of CAD/CAM systems for progressive die design were de-veloped [2–5], though few of them are based on AI techniques. These early systems are characterized by basic computer graph-ics facilities, standardization of die components, and standard-ization of design procedures. They reduced design and drafting lead time. However, as these systems represent design know-how in the form of conventional procedural programming languages, only generation of the die part list and drafting of the assembly and part drawings are executed using computers. The designer still needs to decide most of the important decisions interactively, including strip and die layouts.
Since the late 1980s, significant efforts have been made by worldwide researchers to integrate a wide variety of AI and traditional CAD approaches to develop dedicated progressive die design automation systems, including strip layout design automation.
Knowledge-based approach is a popular AI technique that has been used in intelligent stamping process planning and die design system. For example, researchers at the University of Massachusetts, USA have described a knowledge-based sys-tem for design of progressive stamping dies for a simple hinge part [6]. The system generates the flat pattern geometry and de-velops a strip layout automatically. Researchers at the National University of Singapore have been developing an intelligent pro-gressive die (IPD) design system since the late 1980s. They used feature modeling and rule-based approach to realize automatic punch shape selection, strip layout development, and 3-D die configuration [7, 8]. Based on a feature-relationship tree that de-scribes the stamped metal part and its topological information, model-based reasoning and spatial reasoning techniques have been employed to reason out certain stamping processes and guide the overall planning process to develop the strip layout automatically. Researchers at the Indian Institute of Technology have developed a computer-aided die design system, CADDS, for sheet-metal blanks [9], based on heuristic rule-based reason-ing and parametric programming techniques. The greatest advan- tage achieved by the system is the rapid generation of the most efficient strip layouts. Researchers at the University of Liverpool have worked on design automation for progressive piercing and blanking dies [10, 11]. Their work is based on applying a coding technique to characterize the stamped part geometric features, which is subsequently used to generate the type and layout of the die punches, and then develop the strip layout automatically. Researchers at Huazhong University of Science and Technol-ogy, China, have developed an intelligent progressive die design system, HPRODIE [12]. With feature mapping, rule-based rea-soning and case-based reasoning techniques, most of the design processes including strip layout design can be carried out auto-matically. Researchers at Pusan National University, Korea, have developed a compact computer-aided process planning (CAPP) system for progressive die design [13]. Based on production rules, the work is capable of carrying out an intelligent stamp-ing process planning work with automatic development of blank layout, strip layout and die layout.
Though knowledge-based systems have achieved a lot of suc-cess in stamping process planning, most of the intelligent pro-gressive die design automation prototypes reviewed above are rather restricted to specific application domains, or still need considerable interactive input from experienced designers to de-velop strip layouts. This is because they still inherit the disadvan-tages of the conventional architecture of knowledge-based expert systems, which are incapable of managing heterogeneous KSs effectively.
Researchers at the National Taiwan Institute of Technology have adopted various AI techniques including fuzzy reasoning, pattern recognition, rule-based reasoning, back-propagation neu-ral network, genetic algorithms and Petri nets for the stamping process planning and design of progressive shearing cut and bending dies [14–16]. However their work lacks an explicit and consistent model to integrate these AI techniques into a compre-hensive design environment.
In this paper, another popular AI technique, blackboard ar-chitecture, is adopted to develop a blackboard-based stamping process planning system. In the last two decades, blackboard ar-chitecture has been successfully used in a wide variety of areas, such as speech recognition, signal processing, engineering de-sign and process planning. Thompson and Lu [17] used a black-board architecture to provide a cooperative decision making en-vironment that is suitable for concurrent product and process design. Srihari et al. [18] developed a real-time CAPP system for printed circuit board (PCB) assembly by integrating multiple KSs, including planning expert and dynamic information pro-cessing modules in the blackboard architecture. Chen et al. [19] developed a concurrent product design evaluation system, using a blackboard architecture to classify knowledge into diverse KSs suitable for qualitative and quantitative evaluation, respectively.
In the past few years, blackboard architecture has proven to be suitable for tooling design such as fixture design [20] and in-jection moulding design [21], though this kind of application is still in its infancy stage. Roy and Liao [20] report the preliminary work that investigates the suitability of using a blackboard archi-tecture as a [K1]problem solving model for fixture design. It de- scribes the creation of various functional KSs for fixture design and their organization in a cooperative problem solving environ-ment. Kwong et al. [21] proposes a blackboard-based system for concurrent process design of injection moulding, which facili-tates the simultaneous considerations of moulding part design, tool design, machine-selection, production scheduling, and cost as early as possible in the conceptual design stage. However, we have not found in the literature any attempt to apply the blackboard architecture to stamping process planning for sheet metal parts. It has been mentioned in our earlier work [22] that a blackboard architecture is well suited for constructive prob-lem solving, like process planning of stamping operations, where the problem space is large and knowledge from many different sources must be integrated to achieve a solution. This topic is now to be extensively elaborated in the present paper.
3.Blackboard framework for stamping process planning
Cooperative decision making for knowledge-based stamping process planning involves a variety of KSs such as unfolding knowledge to produce flat pattern, nesting knowledge to produce blank layout, mapping knowledge to transform stamping features into stamping operations, and staging knowledge to sequence the stamping operations. These KSs may be expressed in different representation schemes such as procedures, rules, and objects. This justifies the use of a blackboard framework that can man- age heterogeneous KSs effectively. The KSs interact through the blackboard to develop a solution incrementally.
The proposed blackboard framework consists of three major components: the blackboard data structure, KSs, and a control module (Fig. 1), and was developed using object-oriented expert system shell CLIPS. The different components of the blackboard framework are described as follows.
3.1 Object-oriented blackboard data structure
The blackboard is a globally accessible database, which con-tains the data and partial solutions and is shared by a number of independent KSs. The KSs contribute their partial solutions to the blackboard, which lead to a final solution incrementally. The blackboard is structured as a hierarchy of solution parti-tion levels, which represent different aspects or stages of the solution process. Partial solutions are associated with each level and may be linked to information on other levels using algorith-mic procedures or heuristic rules. Each level contains planning objects that are used to represent the solution space in an object-oriented manner. This leads to the added advantage in knowledge system development because object-oriented approach supports software modularity, reusability, and scalability.
Referring to Fig. 1, the planning solution is partitioned into four different object levels: stamping part, stamping features, stamping operations, and stamping process plan, each represent-ing initial input or different partial solutions posted on the black-board by the specialist KSs. They are described as follows.
3.1.1 Input data to the blackboard
Input data to the blackboard mainly includes the part and press ob-jects. The generic declaration of a part object includes the basic attributes such as part type, part dimensions, weight, surface treat-ments, blank thickness, blank material, annual production, blank dimensions, etc., and points to its constituent stamping feature ob-jects that will be elaborated later on. The press object contains the attributes such as press type, press tonnage, bolster dimensions, bed open dimensions, shut height, number of strokes, etc.
3.1.2 Object-oriented feature modeling to stamped metal parts
Since traditional geometric modeling techniques do not capture design intent (e.g., design for manufacturing), they are in gen-eral unable to support sophisticated and intelligent reasoning capabilities, e.g., knowledge-based process planning. Recently, the concept of machining features has been introduced to cre-ate a direct link between design and manufacturing [23]. Feature modeling is a relatively new way of storing design and manu-facturing information in CAD/CAM/CAPP systems. Similarly, stamping features of a stamped metal part can enable stamping process planning tasks to be performed directly from the geo-metric model. Stamping features are information carriers that are used to model a stamped part with a set of design and manu-facturing information including geometric and non-geometric at-tributes. Each of these stamping features can be manufactured with a specific stamping operation or a combination of stamping operations.
Using the hierarchical classification structure of general de-sign features by Chen et al. [24], a stamped metal part can be modeled with four categories of stamping features:
Primary features: flat, drawing, etc.;
Positive secondary features: tab, curl, emboss, hem, bead, flange, etc.;
Negative secondary features: hole, extrusion hole, profile, de-form, slot, step, etc.; andConnective secondary features: bend, blend, etc.
In this work, the object-oriented feature representation is em-ployed to encapsulate design and manufacturing information in a stamping feature object. For example, a hole feature object contains the basic attributes such as feature type, feature ID, pri-mary feature ID, position, orientation, depth, diameter, precision, roughness, etc., and methods to calculate perimeter.
Besides representation of individual stamping features, a comprehensive representation of feature relations guarantees that all the stamping features associated with stamping process planning are considered. In addition, the data on feature relations are useful for determining the sequence of stamping operations and sometimes the stamping operations themselves. Four criti-cal types of relations among stamping features – “is-in”, “is-on”, “adjacent-to” and “precision-associated” are identified, which have been elaborated in our previous work [25] and won’t be repeated in this paper for conciseness. For example, a precision-associated relation represents design constraints that arise when a stamping feature does not directly connect to, but is associ-ated with, another stamping feature by a toleranced dimension. The feature relation data is also included in the feature object for more complete feature modeling.
3.1.3 Stamping operation objects mapped from stamping feature objects
On the blackboard, the stamping operation objects are in a lower level than the stamping feature objects, and are used to define the manufacturing process from metal strip to the formed metal part. Stamping features constitute a stamped part, while stamp-ing operations are selected as elements of a stamping process plan. Essentially, the stamping process planning task is to trans-form a set of stamping features into a set of stamping opera-tions, and to describe the relations between these. The generic declaration of a stamping operation object includes stamping op-eration type, geometric shapes, geometric constraints, precision, roughness, relationships with stamping features, control param-eters, etc. Typical stamping operation objects include piercing, notching, cut-off, blanking, lancing, shaving, drawing, emboss-ing, coining, trimming, and other miscellaneous forming opera-tions. A stamping feature may be manufactured with a specific stamping operation (one-to-one mapping) or a combination of stamping operations (one-to-many mapping). Several stamping features may also be manufactured with a single stamping oper-ation (many-to-one mapping).
3.1.4 Graph-based stamping process plan
After the mapping from stamping features to a set of stamping operations, the remaining process planning task is to assign each stamping operation to the relevant die station according to an op-timal sequence of stamping operations. Stamping operations are sequenced in a progressive manner by creating stamping opera-tion relations and using them to form a stamping process plan. This formal description of operation relations forms the founda-tion of automatic strip layout design.
A graph-based approach is used to arrange the stamping op-eration objects in a stamping process plan. The graph consists of a set of nodes that store information about the stamping opera-tions, and a set of arcs that store information about the operation relations. Stamping operations are related to one another through two kinds of relationship, “cluster” or “precedence” relations. Cluster stamping operations are executed simultaneously and can be staged at the same die station. Stamping operations in prece-dence must be performed in sequence and so they are staged in adjacent die stations. Cluster relation, and precedence rela-tion are represented by dashed ellipses and directed solid line, respectively, as shown in Fig. 2. Note that stamping operations B and C work simultaneously, and are staged at the same die station, while stamping operation A precedes operation B, and is staged in a die station immediately prior to the one for the operation B.
The strip layout can be generated by a computer automat-ically using the graph-based stamping process plan, which is suited for computer implementation and leads to efficient formu-lation and solution procedures.
以沖壓工藝規(guī)劃知識(shí)進(jìn)行的級進(jìn)模設(shè)計(jì)
摘 要
人們普遍認(rèn)為沖壓工藝規(guī)劃的布局是級進(jìn)模設(shè)計(jì)中的關(guān)鍵任務(wù)。有史以來，沖壓工藝規(guī)劃是一門藝術(shù)，而不是一門科學(xué)。雖然人工智能在將內(nèi)置的智能和應(yīng)用多樣化的知識(shí)窗臺(tái)解決這類問題已經(jīng)取得了很多最新進(jìn)展。而現(xiàn)在主要的困難是，現(xiàn)有的基于知識(shí)的專家系統(tǒng)—沖壓工藝規(guī)劃缺乏適當(dāng)?shù)募軜?gòu)組織異構(gòu)知識(shí)源（KSS）的合作決策EN-vironment。本文提出了沖壓工藝規(guī)劃知識(shí)型面板框架。建議AP-proach通過自動(dòng)售貨機(jī) - 荷蘭國際集團(tuán)的帶狀布局設(shè)計(jì)，加快了級進(jìn)模設(shè)計(jì)過程。
關(guān)鍵詞：基于知識(shí) 面向?qū)ο?級進(jìn)模具設(shè)計(jì) 沖壓工藝規(guī)劃
1.引言
級進(jìn)模在大眾中生產(chǎn)鈑金件已被廣泛應(yīng)用于各種行業(yè)，如航空航天，電子，機(jī)床，汽車。這些模具可在一次裝夾完成穿孔，開槽，切斷，落料，彎曲，刮，拉絲，浮雕，修剪，和