已阅读5页,还剩6页未读, 继续免费阅读
版权说明:本文档由用户提供并上传,收益归属内容提供方,若内容存在侵权,请进行举报或认领
文档简介
英文原文ImprovingPerformanceofProgressiveDiesProgressivediestampingisacost-effectiveandsafemethodofproducingcomponents.Carefuldesignandconstructionofdieswillensureoptimumperformance.Aprogressivedieperformsaseriesoffundamentalsheetmetaloperationsattwoormorestationsinthedieduringeachpressstroke.Thesesimultaneousoperationsproduceapartfromastripofmaterialthatmovesthroughthedie.Eachworkingstationperformsoneormoredieoperations,butthestripmustmovefromthefirststationthrougheachsucceedingstationtoproduceacompletepart.Carriers,consistingofoneormorestripsofmaterialleftbetweentheparts,providemovementofthepartsfromonediestationtothenext.Thesecarrierstripsareseparatedfromthepartsinthelastdiestation.Therearesixelementsthatshouldbeaddressedwhendesigningandbuildingaprogressivedietomaximizeitsperformance:Interpretingthepartprint,Startingmaterialintothedie,Partliftersandpartfeeding,Flexiblepartcarriers,Upperpressurepads,andDrawnshells.InterpretingthePartPrintThefirststepintheproperdesignofaprogressivedieistocorrectlyanalyzethepartprint.Thetooldesignermustinterprettheprinttodeterminethefunctionofthepartbylookingforsuchthingsasthetypeofmaterial,criticalsurfaces,holesizeandlocation,burrlocation,graindirectionrequirements,surfacefinishandotherfactors.Thediedesignermustunderstandthepartwell,particularlyifithasirregularshapesandcontours.However,moderncomputer-drawnprintsmakethismoredifficultbecausecomputer-drawnpartdatacanbedownloadeddirectlytothedie-designcomputer.Asaresult,thedesignermaynotbecomethoroughlyfamiliarwithimportantpartfeatures.Also,manycomputer-drawnpartsaremoredifficulttounderstand,becauseoften,onlyonesurfaceisshownanditmaybetheinsideoroutsidesurface.Computerdrawingsoftenshowalllines,includinghiddenfeatures,assolidlinesinsteadofdottedlines.Thisleadstointerpretationerrors,whichinturnleadstoerrorsinthebuildingofthedie.Tobetterunderstandcomplexpartshapes,itishelpfultobuildasightmodelofthepartusingsheetwax,rubberskinsorwoodmodels.Dimensionalaccuracyisnotcriticalforthesemodels,astheyareusedprimarilytovisualizethepart.Rubberskinsandsheetwaxalsocanbeusedtodeveloppreformshapesandtodevelopthebestpositionsforthepartasitpassesthrougheachdieoperationintheprogressivedie.StartingMaterialintheDieCaremustbetakentoensurethatthestripisstartedcorrectlyintothedie.Improperlocationoftheleadendofthestripwilldomoredamagetothedieinthefirst10strokesofthepressthanthenext100,000strokes.Lead-ingaugesmusthavelargeleadsandaledgetosupporttheleadendofthecoilstripwhenitisinsertedintothedie.Largeleadsonthegaugesareimportantsothatthediesetuppersondoesnothavetoreachintothedie,aswellasforminimizingthetimerequiredtostartanewstripintothedie.Also,onegaugeshouldbeadjustabletocompensateforvariationinstripwidth,.Thepositionoftheleadedgeofthestripiscriticalforthefirstpressstroke,andmustbedeterminedforeverydiestationtoensurethatpiercingpunchesdonotcutpartialholesintheleadedge.Thiscouldcausepunchdeflectionorresultinapartialcutwithtrimmingpunches,whichcanresultinanunbalancedsideloadasthestrippassesthroughthedie.Anyoftheseconditionscanresultinashiftofthepunch-to-dierelationshipthatmaycauseshearingofthepunches.Improperlocationoftheleadedgeofthestripalsocanresultinanunbalancedformingorflangingconditionthatcanshifttheupperdieinrelationtothelowerdie.Heelsshouldberequiredtoabsorbthissideload,particularlywhenformingthickmaterials.Apitchnotchandpitchstopcanprovideaphysicalpointtolocateandcontroltheleadedgeofthestrip.Brasstagsormarkergroovesalsocanprovideavisuallocation,butthesearenotasaccurateoraseffectiveasapitchnotchstop.Thepresscanbepreventedfromoperatingwitheitherashortfeedoroverfeedbymountingthepitchstoponapivotandmonitoringitwithalimitswitch.PartLiftersandPartFeedingProgressivediesoftenrequirethestriptobeliftedfromthenormaldieworkleveltothefeedlevelbeforestripfeedingtakesplace.Thiscanvaryfromasmallamount-tocleartrimandpunchingburrs-toseveralinchestoallowpartshapestoclearthedie.Normally,allliftersshouldrisetothesameheightsothatthestripissupportedinalevelplaneduringforwardfeed.Thestripmustnotsagbetweenlifters;otherwisepartswillbepulledoutoftheircorrectstationlocationspacing.Barliftersprovidegoodsupportandarebetterthanspringpinsorroundliftersnotchedononesideofthestrip.Often,agoodbarliftersystemallowshigherpressspeedsbecausefeedproblemsareeliminated.Althoughtheinitialcostismorethanroundlifters,performanceisbetterandsetuptimeisreduced.Asthestripisstartedintothelead-ingauges,thestripshouldbeabletofeedautomaticallythroughallthefollowingdiestationswithoutrequiringmanualalignmentineachsetofgaugesandlifters.Thestripalsomustbebalancedonthelifterssothatitdoesnotfalltoonesideduringfeed.Aretainercapcanbemountedonthetopoftheoutsidebarlifters.Thisproducesagroovethatcapturesthestripduringfeedandpreventsstripbuckling.Gaugingandlifterconditionscanbesimulatedduringdiedesignbycuttingapieceoftransparentpapertothewidthofthestrip.Theleadedgeofthepaperisplacedovertheplanviewofthediedesignatthelocationthestripwillbeforthefirstpressstroke.Thenthepaperismarkedwithalloftheoperationsthatwillbeperformedatthefirstdiestation-forexample,notchingandpunching.Thepaperstripthenismovedtothesecondstationonthedrawingandtheoperationsforboththefirstandsecondstationsaremarked.Thisprocessisrepeatedthroughallthediestationstoillustratewhattherealpartstripwilllooklikewhenitisstartedintothedieandhelpsdeterminetheadequacyofgaugesandlifters.Totransportthestripfromonestationtothenextinaprogressivedie,somematerialmustbeleftbetweenthepartsonthestrip.Thiscarriermaterialmaybesolidacrossthewidthofthestrip,ormaybeoneormorenarrowribbonsofmaterial,seepartcarrierssidebar.Manypartsrequiretheedgeoftheblanktoflowinwardduringflanging,formingordrawingoperations.Thismayrequirethecarriertomovesidewaysorflexvertically,orboth,duringthedieoperation.Aflexibleloopmustbeprovidedinthecarriertoallowflexingandmovementoftheblankwithoutpullingtheadjacentpartsoutofposition,Fig.2.Anotherconcernistheverticalbreathingofpartsindiestationsduringtheclosingandopeningofthedieinthepressstroke.Forexample,verticalbreathingtakesplacebetweenthedrawstationsofpartsrequiringmorethanonedrawtocompletethepart,Fig.3.Verticalbreathingalsooccurswhenaflangeisformedupinaprogressivediestationthatisadjacenttostationsthatuseupperpressurepadstoholdtheadjacentpartsdown.Itisimportanttoconsidertheflexingofthecarrierduringtheupstrokeofthepressaswellasduringthedownstrokebecausetheactionmaybedifferent.Thiscanbesimulatedinthedesignstagebymakinganoutlineofthecross-sectionofthepart,thepressurepadsandthestationary-mountedsteelsonseparatesheetsofpaperandthenplacingthesesheetsontopofeachotherinlayersoverthediesectionviews.ThiswillshowtherelativepositionofthepartasthedieclosesandduringthereverseactionasthedieramopensPartCarriersAcommonfeatureinallprogressivestampingdiesisthematerialthattransportsthepartsfromstation-to-stationasitpassesthroughthedie.Thismaterialisknownbyvariousterms,suchascarrier,web,strip,tie,attachment,etc.Inthisinstance,wewillusethetermcarrier,ofwhichtherearefivebasicstyles:Solidcarrier-Allrequiredworkcanbeaccomplishedonthepartwithoutpreliminarytrimming.Thepartiscutofforblankedinthefinaloperation.Centercarrier-Theperipheryofthepartistrimmed;leavingonlyanarrowtienearthemiddleofthepart.Thispermitsworktobeperformedallaroundthepart.Awidecentercarrierpermitstrimmingonlyatthesidesofthepart.Lanceandcarryatthecenter-Thestripislancedbetweenparts,leavinganarrowareanearthecentertocarrytheparts.Thiseliminatesscrapmaterialbetweenparts.Outsidecarriers-Thecarriersareattachedtothesidesofthepartsothatworkcanbedonetothecenterofthepart.Onesidecarrier-Thepartiscarriedallthewayorpartofthewaythroughthediewiththecarrierononesideonly.Thispermitsworkonthreesidesofthepart.Thetypeorshapeofthecarrierwillvarydependingonwhatthepartrequiresasitprogressesfromstationtostationinthedie.Thestockwidthmaybeleftsolidifnopartmaterialmotionisrequiredduringdieclosureoritcanbenotchedtocreateone,twooreventhreecarriersbetweenthepartsThecarrierscanbestraight,formazig-zagpatternorhaveloopsbetweenthepartsdependingonwhereattachmentpointstothepartareavailableortoaccommodatewhateverclearancemayberequiredbythedietooling.Asthepartisformed,flangedordrawnintoashell,thecarriermayhavetomovesidewaysorupanddownasthedieclosesandopens.Whendieoperationscausethecarriertomove,itusuallywi
温馨提示
- 1. 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
- 2. 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
- 3. 本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
- 4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
- 5. 人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对用户上传分享的文档内容本身不做任何修改或编辑,并不能对任何下载内容负责。
- 6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
- 7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
最新文档
- 2024人力资源行业分析
- 2023医药行业市场分析
- 结构性金属制品业行业分析
- 注塑行业风口行业分析
- 松江区胶粘剂行业市场分析
- 数据库行业的商业模式分析
- 家纺行业市场规模情况分析
- 塑料制品行业发展背景分析
- 口罩行业威胁分析
- 优势行业劣势行业分析
- 人工智能产业园建设项目可行性研究报告
- 初中八年级语文课件-一滴水经过丽江 优质课比赛一等奖
- 2024年甘肃兰州铁路局集团招聘笔试参考题库附带答案详解
- 压疮用具的使用护理课件
- 质量管理体系与企业档案管理
- 儿童折纸船手工课件
- 直播行业现状SWOT分析
- 2024年中央纪委国家监委驻中国邮政集团有限公司招聘笔试参考题库附带答案详解
- 【京东绿色物流发展现状、问题及优化建议探析14000字(论文)】
- 《说说委屈的事》参考课件
- 古代汉语教程张世禄简体字版
评论
0/150
提交评论