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Generalall-steelpunchingdie’spunchingaccuracy（普通全钢冲模的冲压精度分析）作者：不详来源于：机械论文文档在线免费下载网发布时间：2009-1-220:04:17Generalall-steelpunchingdie’spunchingaccuracyAccuracyofpanelpunchingpartisdisplaythepressaccuracyofthedieexactly.Buttheaccuracyofanypunchingparts’lineardimensionandpositionalaccuracyalmostdependontheblankingandblankingaccuracy,.Sothatthecompoundmouldofcompoundpunching’saccuracy,istypicalnessandrepresentationinthemajority.Analyseofthedie’saccuracyFortheanalyseofpracyicableinaccuracyduringproductionofdiestoinactivation,wecouldgetthetendencywhenitisaugmentationinmosttime.Fromthiswecouldanalysetheelements.Whenthenewpunchdiesptintoproductiontothefirstcuttergrinding,theinaccuracyproducedcalledinitialerror;ifthediegrindingmorethantwentytimes,untilit’sdiscard,theinaccuracycalledconventionalerror;andbeforethediesdiscard,thelargesterrorofthelastbatchpermit,calledlimitingerror.atjobsite,theevidencetoconfirmlifeofsharpeningisthehigheroftheblanking,punchedholeorpunchedparts.Becauseallfinishedpartshadbeenblanked,soitisespeciallyforthecompounddies.Therefore,theanalyseofburrandmeasurementisespeciallyimportantwhendothemasenterprisestandardizationorcheckedwiththeheightofpunchingpart.Theinitialerrorusuallyistheminimalthroughthewholelifeofdie.Itsmagnitudedependontheaccuracyofmanufacture,quality,measureofthepunchingpart,thicknessofpanel,magnitudeofgapanddegreeofhomogeneity.Theaccuracyofmanufacturedependonthemanufactureprocess.Forthe1mmthickedcompoundpunchingpartmadeinmediumsteel,theexperimentalresultandproductivepracticeallprovethattheburrofdieswhichproducedbysparkcuttingarehigher25%~~30%thanproducedbygrinder,NCorCNC.ThereasonisthatnotonlythelatterhavemoreexactmachiningaccuracybutalsothevalueofroughnessRaislessoneorderthantheformmer,itcanbereached0.025μm.Therefore,thedie’sinitialblankedaccuracydependsontheaccuracyofmanufacture,qualityandsoon.Thenormalerrorofthepunchdieisthepracticableerrorwhenthefistcuttergrindingandthelastcuttergrindingbeforethedieproducethelastqualifiedproduct.Astheincreaseofcuttergrinding,causedthemeasurethenaturewearofthediesaregradualincreasing,theerrorofpunchingpartincreasealso,sothepartsareblewproof.Andthediewillbeunused.Theholeonthepartandinnerbecausethemeasureofwearwillbesmallandsmallgradually,anditsoutsideformwillbelagerinthesamereason.Therefore,theholeandinnerforminthepartwillbemademouldaccordingtoone-waypositivedeviationornearlyequaltothelimitmaxmeasure.Inlikemanner,thepunchingpart’sappearancewillbemademouldaccordingtoone-waynegativedeviationornearlyequaltolimitminimeasure.Forthiswillbebroadenthenormalerror,andthecuttergrindingtimeswillbeincreased,thelifewillbelong.Thelimiterrorinpunchingpartsarethemaxdimensionerrorwhichpracticableallowedinthepartswithlimiterror.Thiskindofpartsusuallyarethelastqualifiedproductsbeforethediediscard.Fortheallclassesofdies,ifweanalysethefluctuate,tendencyofincreaseanddecreaseandlawwhichappearedinthedie’swholelife,wewillfindthatthemasteroftheerrorarechangeless;theerrorthatbecausetheabradeofthecutterandimpressionwillbeasthecuttergrindingtimesincreasedatthesametime.Andthatwillcausetheerroroversizegradually;andalsohaveanotherparterrorareunconventional,unforeseen.Therefore,everydie’serrorarecomposedoffixederror,systemerror,accidenterrorandsoon.1.fixederrorAtthewholeprocesswhentheNewpunchingdiebetweenjustinputproductiontodiscard,thechangelessmastererrorthatinqualifiedpartarecalledfixederror.It’smagnitudeisthedeviationwhenthedieproductionqualifiedproductsbeforethefirstcuttergrinding.Alsoistheinitialerror,butthediehaveinitialpunchingaccuracyatthistime.Becauseoftheabradeofparts,thedieaftergrindingwillbechangethedimensionerror.Andtheincrementofdeviationwilloversizeasthetimesofcuttergrinding.Sothepunchingaccuracyaftercuttergrindingalsocalled“grindingaccuracy”andlowertaninitialaccuracy.Thefixederrordependontheelementsfactorasfollowed:(1)thematerial,sorts,structure,(form)dimension,andthickofpanelthemagnitudeofpunchinggapanddegreeofhomogeneityarehaveaimportanteffectforthedimensionaccuracy.Differentpunchingprocess,material,thickofpanel,havecompletelydifferentgapandpunchingaccuracy.AgearH62whichmadeinyellowbrasswiththesamemodenumberm=0.34,2mmthickandhadacenterhole,whenthegapgetC=0.5%t(singleedge),andpunchedwithcompoundpunchingdie,andthedimensionaccuracyreachedIT7,theparthaveaflatsurface,theverticalityoftangentplanereached89.5°,itsroughnessRamagnitudeare12.5μm,heightofburrare0.10mm;andthepunchingpartarepunchedwithprogressivedie,thegapC=7%t(singleedge),initialaccuracyareIT11,andhaveanmoreroughsurface,evencanseethegapwitheyes.Intheusualsituation,flushesamaterialanditsthicknesstistheselectionpunchinggapmainbasis.Oncethedesignationgaphaddeterminedflushestheplanesizethefixederrormainbody;Flushesthestructurerigidityandthethree-dimensionalshapeaffectsitsshapepositionprecision.(2)punchingcraftandmolderstructuretypeUsesthedifferentrammingcraft,flushesaprecisionandthefixederrordifferenceisreallybig.Exceptthattheabovepiecegearexampleshowed,theessenceflushesthecraftandordinarypunchingflushesap