DomesticandforeigncarcoverageDieDesignOverviewA.S.Pouzada,E.C.FerreiraandA.J.PontesAbstract:Inintroducingthecurrentdomesticcarstampingdiedesignandmanufactureofthefoundation,expoundedforeignautocompanycarspanelparticularpanelofthestampingprocessanddiedesignstatusapplicationofnewtechnologies.Keywords:mechanicalmanufacturing;Carpanel;Stampingtechnology;MoldDesign1IntroductionInrecentyears,China'scarmarkethasdevelopedveryrapidlyin2002incarsalesmorethanonemilliononthebasisofin2003to2millionpeoplerelationsforward,reaching1.97million.However,inthecarheatrapidlywarming,hadtofacetheembarrassmentofthisreality-marketbest-sellingvehicleforthemajorityofpeoplemustbedirectlyimportedfromabroad.Asdomesticcarcovermolddesignandmanufacturingcapabilityonthewholeisrelativelyweak,inordertoproducethesemodels,eachcompanyhadtospendhundredsofmillionsorhundredsofbillionofoverseasprocurementdie.Peoplewithforeignautomobilecompanies,becausetherelativelysmallscaleofproduction,Thishasresultedinmotorcyclesmoothingwoodintothemoldmuchhigherthanforeigncars,Thisisalsoproducedcarsalongwithhighwoodmanufacturingintooneofthemainreasons.2DomesticcarcoverageDiedevelopmentcapabilityMajorcarmanufacturerstoDie:DieManufacturingCo.Ltd.ofFAW,DongfengMotorDieWorks,TianjinAutomobileDieCompany,CACIntegrationTechnologyCo.,LtdNanjingmoldequipment,ShanghaiAutoBody1000marginDieCompany.Mostpeopleasadomesticcarproductionandsalesofcommercial-vehiclepopulationofShanghaiLimited,alsohasitsownmolddesignandmanufacturingdepartments((TMMDivision).Currently,AlthoughdomesticDieinCarcoverthemolddesignandmanufacturinghasasmallcapacity,autoplantscanundertakesomedevelopmentprojectsdie,butforaveryhighsurfaceaccuracyandsurfacequalityrequirementsoftheoutsidepanel.Itisespeciallythehigh-gradecarsoutsidepanel,autoplantsrarelydiebythewillofsuchdomesticdevelopment.ShanghaiPublicMotorsLimitedinordertoreducevehicleproductioncosts,butalsotoincreasethecompany'scoretechnicalcompetencies,Sincethebeginningof2001,setfootinthecarstampingdiedesignandmanufacturingfields.2001-2002completedPOLOcarsmanuallypressestheproductionline10Diesimpleparts,thecompany'squalityassurancedepartmentaswellandputintoproduction.Beginningin2002,thetypeofpeopletothecomplex,automation,6000kNthedesignandmanufactureofautomaticproductionlinePOLOcarstyres.DieBlock(dimensionsoftheparts,deepdrawingdeep,complexshape)in2003,inordertofurtherenhancethedesignandmanufactureofmoldabilityandlevelWegetinvolvedintheMulti-Position20000kNPressand10000kNautomaticproductionlineofdiedesign.Shanghaioverthepastnumberofpeopleinmanypublicspaces20000kNPressontheuseofthemold,alluneedtoprogress,Diedomesticbusinessstilllackstheabilitytodesignandmanufacturethemold.Tothisend,wechosePOLOCarcolumnplatemolddesign.20000kNMulti-PositionPressistheworld'smostadvancedpresses,integration,averyhighdegreeofautomation.Ofcourse,thisrightmolddesignrequirementsalsoincreasedaccordingly.PartsFeedingheight,distance,locationmanipulatorstrictrequirementsensurethatthemanipulatorinthecourseofthecampaignanddiewithoutinterference,sothemolddesignforspaceonasmalllot.Inconsideringmanyfactors,wefinallycompletedthewholemolddesign,CADstateassemblyasshowninfigure1.Inaddition,wehavecompletedthePOLOcars10000kNautomaticproductionlineoftherearwheelcovermolddesign,Inlastyear'sbuildonthat.ThesesuccessfulcompletionoftheShanghaimarksthenumberofpeoplediedesigncapabilityhasreachedadvanceddomesticlevel.thusforthefutureofShanghaipeopledieDomesticcarlayasolidfoundation.Nevertheless,withtheinternationaladvancedlevel,themorepeopletherearestillgaps,Forexample,inthecaroutsidecovermolddesignorfromtheair.Molddesigncomplete,thecombinationofdrawingsthroughthebubbleacceptancemodel(Figure3)differentprocedureswithdifferentcolorsofthelinesmarkingthebubblemodel,thesointuitiveandclear.Technologyshouldalsobeorganized,includingdesigners,projectplanning,moldtesting,Dieoperatorsandotherstakeholderstodiscussacceptance.Forthestampingprocessdifficulttosolvetheproblemofforming,productdevelopmentshouldalsobeinvitedtodiscusspersonnel,lookforchangesinproductdesignpossibilities.3.2ReboundamendmentresponseTheformerisknown,thereboundwascarsoutsidepanelformingprocessofthemainquestionsarecoveredplatebeforeexample,conductdetailedanalysis.①Usuallypanelofthereboundfollowingtwocategories:Largeflatsurfacecausedbytheelasticresponseofbucklingorcollapse,asillustratedinfigure4,PartCClickbelow,dottedsaidpartsremovedfromthemoldandreboundoccurredaftertheposition.Insuchcases,thedesignprocessisnotnormallybeconsidered.Technologyproductsinafewdie-facewithsomeofthedatafromtheproductdevelopmentdepartmentsofconsistentdata,andfordiemanufacturing.Totryout,andthespecimenswereseizedcomparedwithmeasurements,accordingtothedeviationofdrawingsurfacemodelamendment.Ifdesignerstocontrolsuchproblemshaveveryrichexperience,canbeestimatedinadvancesurfaceelasticrecoveryandthedirectionofoffset,andwillreverseitssuperpositionofseveralproduct-development,Reboundconsiderseekingdeformationofthesurfaceofdeepdrawingprocess,thecalculationprocessrequiresspecializedcomputersoftwaretoaccomplish,InGermanypublic,usingtheICEM.②Flangingplasticpartbybendingthereboundfoldanglechanges,asillustratedinfigure4BClickbelow.Forthiskindofproblem,inadditiontotheDepartmentofDrawingandcuttingedge,butalsoincludingflangingandWedgeplastic,plastictake-offprocessisforming2-3,tooffsetthespringback.Theprocessdesignworkcompletedandreflectedinthenumberofprogrammodules.3．3WedgenewouterbodymoldcoverageontheapplicationCurrently,manyofthenewmodelsoutsidepanel,fenderpanels(Figure5)frontcoverplate,theroofflangingplasticprocesses,usedasa"revolvingWedge,"newtechnology.Theworkingprincipleseefigure6,rotatingWedgepartofthecavityisrequiredplasticstampingpartsoftheregion,whentheplasticprocessiscomplete,Cylinder-drivencarrierstopromoteWedgearoundrotatingdrumrotation,soastoachievethepurposeoftheyieldcomponents,Aftertheconvenienceofplasticparts,removedfromthemold.RotatingWedge'sadvantagesare:plasticpartsforstampingpartsandmaterialsentrustedpartofthemosaicisveryfairing,Therefore,thereisnoobviouspartsindentation;Diesimplestructure;maintenanceissimpleandlowcost.4ConcludingremarksInrecentyears,throughthetirelesseffortsandthecarstampingdiedesignandmanufacturingcapabilitiesmadesignificantprogress.However,thecarisespeciallyluxurycarsoutsidethecoverageofmolddevelopment,theinternationallevelandtherearestillmorepeoplegap.However,thisgapisnotnarrowing,Solongaswestrengtheninternationalexchangesandlearnfromtheirforeigncounterpartsindesigningandmanufacturingexperience,carwillbeabletoacceleratethecoverageDiedomesticprocess.References[1]C.BurkeandR.Malloy,Anexperimentalstudyoftheejectionforcesencounteredduringinjectionmolding,SPEANTECTech.Pap.37(1991).[2]R.Balsamo,D.HaywardandR.Malloy,Anexperimentalevaluationofejectionforces:frictionaleffects,SPEANTECTech.Pap.39(1993).[3]A.J.PontesandA.S.Pouzada,Ejectionforceintubularinjectionmoldings.PartI:Effectofprocessingconditions,Polym.Eng.Sci.44(2004),p.891.[4]G.MengesandH.Bangert,Measurementofcoefficientsofstaticfrictionasameansofdeterminatingopeninganddemouldingforcesininjectionmoulds,Kunstst.Ger.Plast.71(1981),p.552.[5]B.J.AraújoandA.S.Pouzada,Designofejectionsystemsforinjectionmoulds,OMolde54(2002),p.36.[6]A.J.Pontes,A.M.Pinho,A.S.MirandaandA.S.Pouzada,Effectofprocessingconditionsonejectionforcesininjectionmoulds,OMolde34(1997),p.25.[7]P.Collins,E.M.A.Harkin-JonesandP.J.Martin,Theroleoftool/sheetcontactinplug-assistedthermoforming,Intern.Polym.Process.17(2002),p.361.[8]P.Blau(Ed.),Friction,LubricationandWearTechnology,ASMHandbook,vol.18,ASMInternational,Ohio,1992,p.8.[9]N.A.WatermanandM.F.Ashby,TheMaterialsSelectorvol.3,Chapman&Hall(1997).[10]D.I.JamesandW.G.Newell,Anewconceptinfrictiontesting,Polym.Test.1(1980),p.9.[11]M.Vaziri,F.H.StottandR.T.Spurr,Studiesofthefrictionofpolymericmaterials,Wear122(1988),p.313.[12]R.MalloyandP.Majeski,Designofpinejectorsystemsforinjectionmolds,SPEANTECTech.Pap.47(1989).[13]P.A.Dearnley,Lowfrictionsurfacesforplasticinjectionmouldingdies—anexperimentalcasestudy,Wear229(1999),p.1109.[14]T.Sasaki,N.Koga,K.Shirai,Y.KobayashiandA.Toyoshima,Anexperimentalstudyonejectionforceofinjectionmolding,J.Precis.Eng.24(2000),p.270.[15]A.J.Pontes,R.Pantani,G.TitomanlioandA.S.Pouzada,Ejectionforceintubularinjectionmoldings.PartII:Apredictionmodel,Polym.Eng.Sci.45(2005),p.325.[16]FrictionandWearTestingSourceBook,ASMInternational,Ohio,1997.[17]ISO8295,Plastics—FilmandSheeting—DeterminationoftheCoefficientsofFriction,1995.國(guó)內(nèi)外轎車覆蓋件模具設(shè)計(jì)概況A.S.Pouzada,E.C.FerreiraandA.J.Pontes摘要:在介紹目前國(guó)內(nèi)轎車沖壓模具設(shè)計(jì)制造情況的基礎(chǔ)上，闡述了國(guó)外汽車公司轎車覆蓋件特別是外覆蓋件的沖壓工藝設(shè)計(jì)現(xiàn)狀及模具新技術(shù)應(yīng)用情況。關(guān)鍵詞:機(jī)械制造;轎車覆蓋件;沖壓工藝;模具設(shè)計(jì)

1前言近幾年來(lái)，我國(guó)轎車市場(chǎng)發(fā)展十分迅猛，2002年在轎車銷售超過(guò)100萬(wàn)輛的基礎(chǔ)上，2003年則向200萬(wàn)輛大關(guān)邁進(jìn)，達(dá)到了197萬(wàn)輛。然而，在轎車熱迅速升溫的同時(shí)，不得不尷尬地面對(duì)這樣的現(xiàn)實(shí)—市場(chǎng)上熱銷的絕大多數(shù)車型是直接從國(guó)外引進(jìn)的。由于國(guó)內(nèi)轎車覆蓋件模具設(shè)計(jì)制造能力從總體上看還比較薄弱，為了生產(chǎn)這些車型，各大汽車公司不得不耗資幾億、十幾億元采購(gòu)海外模具。與國(guó)外大汽車公司相比，由于生產(chǎn)規(guī)模比較小，這就造成單車均攤的模具成本遠(yuǎn)高于國(guó)外車，這也是造成國(guó)產(chǎn)車整車制造成木居高不下的主要原因之一。2國(guó)產(chǎn)轎車覆蓋件模具開(kāi)發(fā)能力國(guó)內(nèi)主要的轎車模具制造商有:一汽模具制造有限公司、東風(fēng)汽車模具廠、天津汽車模具有限公司、成飛集成科技股份有限公司、南京模具裝備有限公司、上海千緣汽車車身模具有限公司等等。作為國(guó)內(nèi)最大轎車生產(chǎn)銷售商—上海大眾汽車有限公司，也有自己的模具設(shè)計(jì)制造部門((TMM部)。目前，雖然國(guó)內(nèi)模具商在轎車內(nèi)覆蓋件模具設(shè)計(jì)制造方面已小有能力，并可承接整車廠的部分模具開(kāi)發(fā)項(xiàng)目，但對(duì)于有很高型面精度和表面質(zhì)量要求的外覆蓋件，特別是中高檔轎車的外覆蓋件，整車廠很少會(huì)將這類模具交由國(guó)內(nèi)開(kāi)發(fā)。上海大眾汽車有限公司為了降低整車生產(chǎn)成本，同時(shí)也為了提高公司的核心技術(shù)能力，從2001年開(kāi)始，涉足轎車沖壓模具設(shè)計(jì)制造領(lǐng)域。2001年-2002年完成了POLO轎車在手動(dòng)壓機(jī)線上生產(chǎn)的10只簡(jiǎn)單零件的模具，通過(guò)了公司質(zhì)保部門驗(yàn)收并投產(chǎn)。2002年開(kāi)始向大型化、復(fù)雜化、自動(dòng)化發(fā)展，設(shè)計(jì)制造了6000kN自動(dòng)線上生產(chǎn)的POLO轎車備胎座模具(該零件外形尺寸大、拉深深度深、形狀復(fù)雜)2003年，為進(jìn)一步提高模具設(shè)計(jì)制造的能力和水平，我們涉足20000kN多工位壓力機(jī)和10000kN自動(dòng)線生產(chǎn)使用的模具設(shè)計(jì)。過(guò)去上海大眾在20000kN多工位壓力機(jī)上使用的模具，全部需進(jìn)u,國(guó)內(nèi)模具商還沒(méi)有能力設(shè)計(jì)制造這樣的模具。為此，我們選擇了POLO轎車中柱內(nèi)板的模具進(jìn)行設(shè)計(jì)。20000kN多工位壓力機(jī)是世界上最先進(jìn)的壓力機(jī)之一，集成化、自動(dòng)化程度非常高，當(dāng)然這對(duì)模具設(shè)計(jì)的要求也相應(yīng)地提高。零件的送料高度、步距、機(jī)械手的位置有嚴(yán)格的要求，還要保證機(jī)械手在運(yùn)動(dòng)過(guò)程中與模具無(wú)干涉，這樣給予模具設(shè)計(jì)的空間就小了很多。在考慮諸多因素之后，我們最終完成了整套模具的設(shè)計(jì)，其CAD裝配狀態(tài)如圖1所示。另外，我們還完成了POLO轎車在10000kN自動(dòng)線上生產(chǎn)的后輪罩的模具設(shè)計(jì)，在去年的基礎(chǔ)上更進(jìn)一步。這些工作的順利完成，標(biāo)志著上海大眾模具設(shè)計(jì)能力已經(jīng)達(dá)到了國(guó)內(nèi)先進(jìn)水平，從而為今后上海大眾汽車模具國(guó)產(chǎn)化打下了堅(jiān)實(shí)的基礎(chǔ)。盡管如此，與國(guó)際先進(jìn)水平比較，仍有較大差距，比如在轎車外覆蓋件模具設(shè)計(jì)方面還是空自。在轎車沖模中，難度最大的是外覆蓋件模具設(shè)計(jì)，主要表現(xiàn)在以下兩個(gè)方面:(1)克服由回彈造成的零件型面偏差破裂、起皺、回彈是轎車沖壓件成形過(guò)程中的主要缺陷，由于轎車外覆蓋件外形尺寸大、拉深深度淺、塑性變形程度低，一般不易拉裂，因而回彈就成為該類零件制造過(guò)程中的主要問(wèn)題，它將嚴(yán)重影響零件間的相互配合關(guān)系。有限元模擬軟件在沖壓模具設(shè)計(jì)中得到普遍應(yīng)用，已經(jīng)能夠比較準(zhǔn)確地預(yù)測(cè)破裂和起皺，從而有助于設(shè)計(jì)合適的工藝補(bǔ)充面來(lái)改善拉深過(guò)程中材料的流動(dòng)狀況，提高零件的成形ft。然而，迄今為止，大多數(shù)有限元軟件還不能精確地預(yù)測(cè)沖壓件從模具當(dāng)中取出后的回彈變形。因此，對(duì)外覆蓋件回彈問(wèn)題的處理，主要還是依靠經(jīng)驗(yàn)來(lái)修改模具型面，使沖壓件過(guò)正成形，來(lái)抵消由于回彈導(dǎo)致的變形。(2)沖壓件的取件由于外覆蓋件(如前蓋外板、車頂、翼子板)都需進(jìn)行復(fù)雜的翻邊整形或預(yù)卷邊工藝，這就使得在模具結(jié)構(gòu)設(shè)計(jì)時(shí)，必須考慮沖壓件成形后的取件問(wèn)題，目前，大都依靠復(fù)雜的多斜楔機(jī)構(gòu)聯(lián)動(dòng)來(lái)實(shí)現(xiàn)模具工作部分對(duì)零件讓位，以實(shí)現(xiàn)方便取件，由此造成整個(gè)模具的結(jié)構(gòu)十分復(fù)雜。3國(guó)外覆蓋件模具設(shè)計(jì)目前，國(guó)外大汽車公司為了降低模具開(kāi)發(fā)、制造成本，縮短生產(chǎn)周期，將除轎車外覆蓋件之外的大部分轎車沖壓件的模具都交由專業(yè)模具公司(如FontanaPietro.Kuka.Laepple.SchulerCartec.Ogi-hala-FujiTechniaca等等)設(shè)計(jì)和制造，這些公司都有很強(qiáng)的開(kāi)發(fā)能力，并在某些零件的模具制造方面擁有獨(dú)到的優(yōu)勢(shì)。但作為整車廠，考慮到新車型開(kāi)發(fā)過(guò)程中的保密，對(duì)諸如翼子板、行李箱蓋、車門、側(cè)圍、車頂、前蓋等敏感零部件的模具，則都由自己的模具制造部門來(lái)設(shè)計(jì)和制造。3.1軟件環(huán)境沖壓模具設(shè)計(jì)，除了必要的CAD軟件之外，還大量應(yīng)用了有限元模擬軟件，如AutoForm.PamStamp.DynaForm.Indeed等，來(lái)輔助沖壓工藝設(shè)計(jì)。下面，以AutoForm為例，說(shuō)明如何利用CAE軟件來(lái)設(shè)計(jì)拉深工序工藝補(bǔ)充面。AutoForm是一款由瑞士開(kāi)發(fā)的專業(yè)薄板成形快速模擬軟件，可以用于薄板、拼焊板的沖壓成形、液壓脹形等過(guò)程的模擬，配合不同的功能模塊，還可以進(jìn)行沖壓件單步法成形模擬以及拉深工序工藝補(bǔ)充面((Addendum)的設(shè)計(jì)。轎車沖壓件中，約有2/3可以利用AutoForm的DiedesignerModule模塊設(shè)計(jì)Addendum，該模塊根據(jù)由設(shè)計(jì)者指定的或由軟件自動(dòng)產(chǎn)生的壓邊圈型面，以及工藝補(bǔ)充面的多條截面線(Profile)，能夠快速地生成工藝補(bǔ)充面，用于拉深工序的模擬，如圖2所示。壓邊圈型面、Profile均可進(jìn)行參數(shù)化式的調(diào)整。這種快速設(shè)計(jì)是建立在對(duì)Addendum曲面的粗略構(gòu)造上的，即曲面面片本身以及曲面面片之間的連續(xù)并非十分光順，盡管這種曲面不能夠直接用于模具表面的機(jī)械加工，但是對(duì)于模擬精度的影響卻不是很大。根據(jù)模擬結(jié)果，設(shè)計(jì)者可以很方便地對(duì)工藝補(bǔ)充面進(jìn)行調(diào)整，直到模擬結(jié)果滿足設(shè)計(jì)要求。最后，將壓邊圈、Addendum曲面和Profile以中性數(shù)據(jù)格式IGS或VDA輸出，在CAD軟件中進(jìn)行曲面重構(gòu)，并結(jié)合產(chǎn)品數(shù)模，就能夠得到機(jī)加工可以使用的拉深工序模具數(shù)模。沖壓工藝傳統(tǒng)設(shè)計(jì)方法:首先，在經(jīng)驗(yàn)基礎(chǔ)上，利用CAD設(shè)計(jì)工藝補(bǔ)充面;其次，將CAD數(shù)模傳遞給AutoForm等CAE軟件進(jìn)行拉深過(guò)程模擬;根據(jù)模擬結(jié)果，在CAD中對(duì)工藝補(bǔ)充面進(jìn)行調(diào)整，并將新的CAD數(shù)模傳遞給CAE，開(kāi)始新的模擬，直到滿足要求為比。這是一個(gè)從CAD到CAE再回到CAD的不斷反復(fù)的過(guò)程。由于每次在CAD中構(gòu)造曲面都遠(yuǎn)較在AutoForm中復(fù)雜，因此，整個(gè)過(guò)程所花費(fèi)的時(shí)間就多得多。而新方法在沖壓工藝設(shè)計(jì)初期，就用DiedesignerModule在AutoForm軟件中設(shè)計(jì)并調(diào)整拉深工藝補(bǔ)充面，與傳統(tǒng)的設(shè)計(jì)方法相比，就能夠大大提高設(shè)計(jì)效率。由于AutoForm是一款快速模擬軟件，為了在較短的時(shí)間內(nèi)對(duì)復(fù)雜沖壓件的成形過(guò)程進(jìn)行評(píng)價(jià)，采用了膜單元來(lái)離散幾何模型，必然要降低模擬精度，因此，有些汽車公司在模具設(shè)計(jì)開(kāi)始之前還要利用模擬精度高的CAE軟件，如德國(guó)大眾就采用了Indeed軟件，對(duì)拉深工序進(jìn)行再次模擬((Indeed軟件的計(jì)算是基于帶厚度的殼單元的，能夠得到更為準(zhǔn)確的計(jì)算結(jié)果，但是其計(jì)算所花費(fèi)的時(shí)間通常是AutoForm的幾到十幾倍，該軟件比較適用于最終驗(yàn)證)，所有拉深工藝必須通過(guò)Indeed模擬并驗(yàn)證為是可行的，才可用于模具設(shè)計(jì)。模具設(shè)計(jì)完備，應(yīng)通過(guò)圖紙結(jié)合泡沫模型進(jìn)行驗(yàn)收(圖3)，各道工序用不同顏色的線條標(biāo)記在泡沫模型上，這樣做直觀而清晰。還應(yīng)組織包括工藝設(shè)計(jì)者、項(xiàng)目規(guī)劃員、模具調(diào)試人員、模具操作者等相關(guān)人員進(jìn)行討論驗(yàn)收。對(duì)于在沖壓工藝上難以解決的成形問(wèn)題，還應(yīng)邀請(qǐng)產(chǎn)品開(kāi)發(fā)人員一同討論，尋求對(duì)產(chǎn)品進(jìn)行更改設(shè)計(jì)的可能性。3.2修正回彈的對(duì)策由前已知，回彈是轎車外覆蓋件成形過(guò)程中的主要問(wèn)題，現(xiàn)以前蓋外板為例，對(duì)此進(jìn)行詳細(xì)分析。通常外覆蓋件的回彈有以下兩類:①大片平坦曲面由彈性回復(fù)造成的拱起或塌陷，如圖4中C部放大所示，虛線表示零件從模具中取出并發(fā)生回彈后的位置。這類問(wèn)題，工藝設(shè)計(jì)時(shí)通常不加以考慮，工藝數(shù)模中產(chǎn)品型面部分的數(shù)據(jù)與來(lái)自于產(chǎn)品開(kāi)發(fā)部門的數(shù)據(jù)相一致，并用于模具制造。待試模之后，將試件與檢具進(jìn)行對(duì)比測(cè)量，根據(jù)偏差對(duì)拉深模型面進(jìn)行修正。如果設(shè)計(jì)人員對(duì)于這類問(wèn)題的控制擁有非常豐富經(jīng)驗(yàn)的話，也可以事先估計(jì)出曲面彈性回復(fù)的方向以及偏移量，并將其反向疊加到產(chǎn)品數(shù)模上去，求得考慮回彈變形的拉深工藝曲面，這個(gè)計(jì)算過(guò)程需要由專門的計(jì)算機(jī)軟件來(lái)完成，在德國(guó)大眾，采用的是ICEM。②翻邊整形部分由彎曲變形回彈造成的折邊轉(zhuǎn)角變化，如圖4中B部放大所示。對(duì)于這類問(wèn)題，該處除拉深和剪邊外，還包括翻邊和斜楔整形，整形工藝需過(guò)正成形2-3，以抵消彎曲回彈。該工作由工藝設(shè)計(jì)完成，并體現(xiàn)在工藝方案的數(shù)模中。3.3新斜楔機(jī)構(gòu)在外覆蓋件模具上的應(yīng)用目前，新車型的很多外覆蓋件，如翼子板(圖5)前蓋外板、車頂?shù)鹊姆呎喂ば蛑校捎昧艘环N稱之為“旋轉(zhuǎn)斜楔”的新工藝。其工作原理見(jiàn)圖6，旋轉(zhuǎn)斜楔上的凹槽部分是沖壓件需整形的區(qū)域，當(dāng)整形過(guò)程完成后，氣缸驅(qū)動(dòng)的托架推動(dòng)旋轉(zhuǎn)斜楔繞滾筒轉(zhuǎn)動(dòng)，從而達(dá)到對(duì)零件讓位的目的，方便整形后的零件從模具上取出。旋轉(zhuǎn)斜楔的優(yōu)點(diǎn)是:因整形部分與沖壓件托料部分的拼接處非常光順，故零件上無(wú)明顯壓痕;模具結(jié)構(gòu)簡(jiǎn)單;維修保養(yǎng)簡(jiǎn)便且費(fèi)用低。

4結(jié)束語(yǔ)近年來(lái)，通過(guò)不懈的努力，國(guó)內(nèi)轎車沖壓模具的設(shè)計(jì)制造能力取得了顯著的進(jìn)步。但是，在轎車特別是中高檔轎車外覆蓋件模具的開(kāi)發(fā)上，我們與國(guó)際水平仍有較大差距。不過(guò)，這種差距并非不能縮小，只要我們多加強(qiáng)國(guó)際交流，多吸取國(guó)外同行的設(shè)計(jì)制造經(jīng)驗(yàn)，一定能夠加快轎車覆蓋件模具的國(guó)產(chǎn)化進(jìn)程。參考文獻(xiàn)[1]C.BurkeandR.Malloy,Anexperimentalstudyoftheejectionforcesencounteredduringinjectionmolding,SPEANTECTech.Pap.37(1991).[2]R.Balsamo,D.HaywardandR.Malloy,Anexperimentalevaluationofejectionforces:frictionaleffects,SPEANTECTech.Pap.39(1993).[3]A.J.PontesandA.S.Pouzada,Ejectionforceintubularinjectionmoldings.PartI:Effectofprocessingconditions,Polym.Eng.Sci.44(2004),p.891.[4]G.MengesandH.Bangert,Measurementofcoefficientsofstaticfrictionasameansofdeterminatingopeninganddemouldingforcesininjectionmoulds,Kunstst.Ger.Plast.7