拉伸模系数Modulus of drawingWord文档下载推荐.docx
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拉伸模系数Modulus of drawingWord文档下载推荐.docx
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WhenR1=R2,D=
R1=R2
D=
Five、drawingcoefficientofcylindricalparts
1.conceptofdrawingcoefficient.
ThedrawingcoefficientreferstotheratioofDoftheworkpiecediametertoDoftheblankdiameterbeforedrawing.
M=d/D
A.(M<
1)drawingcoefficientMreflectsthemagnitudeofmaterialdeformationduringdrawing,andthesmallertheM,thegreaterthedegreeofdeformation.
B.drawingcoefficientMisanimportantparameterindrawingprocess,anditisanimportantbasisfordrawingprocesscalculationanddiedesign.
C.inactualproduction,inordertoreducethedrawingtimes,Mgenerallytakestheminimumvalue.
D.whenMissmalltoacertainvalue,theouteredgeoftheflangewillappearwrinkling,butitcanincreasetheBHFofthepressureringtopreventtheappearanceofwrinkles.
E.whenMissmalltoacertainvalue,tensilefractureoccurs,andtensilefractureoccursatthepeakofdrawingforce,thatis,theinitialstageofdrawing.
F.limitdrawingcoefficient,theminimumdrawingcoefficientwhichcanbeusedintheconditionthatthedangeroussectionisnotbroken.
2.factorsaffectingdrawingcoefficient:
MechanicalpropertiesofA.materials.Theplasticityofthematerialisgood,theyieldratioissmallerthanthatofthesigmas/sigmaB,andtheMcanbesmaller,becausethesigmaSissmall,indicatingthatthematerialiseasytodeform,andthesigmaBislarge,indicatingthatthedangeroussectionhashighbearingcapacityandisdifficulttobreak.
TherelativethicknessofB.roughcastt/D
C.drawingmethod:
whenthereisapressurering,thedrawingcoefficientMcanbesmaller.
D.diestructure:
drawingdieconvex,concavediefilletsize,andconvex,concavedieclearancebetweenthesizeofthedrawingcoefficientgreatlyaffected.
E.frictionandlubricationrequirements:
die,pressureringandblankcontactsurfaceshouldbesmooth,butrequirelubrication,punchandblankcontactsurfacetorough,nottoincreaselubrication,friction,reducingthepossibilityofcracking.
3.determinationofdrawingcoefficient:
Becausetherearemanyfactorsaffectingthedrawingcoefficientofmaterials,thetheoreticalcalculationandtheactualdifferencearetoolarge,andthedrawingcoefficientsofvariousmaterialsareobtainedbyexperimentalmethods.
Six、classificationofdrawingdie:
1.againdrawingdie:
itisthesemiroughsetinpressureringpositioning,diedown,punchdieonthesemi-finishedblankpulledintothedie,thesemi-finishedproductofreduceddiameter,themaindifferenceis:
theblankholderandthefirstdrawingblankholderisdifferent.
2.compounddrawingdie:
thedeepdrawingdieplaystheroleofblankingpunch.
Manypeopleflinchinthedrawingdie,thisisnotonlybecauseofthedrawingdiedesignmustconsidermanyfactors,moreimportantisinthetestmodeisoftennotamolding,evenafterrepeatedrepairmode,toachievethedesiredresults.Therefore,accumulatingexperienceinpracticeisofgreatbenefittothedesignofdrawingdie.
1.materials:
Goodmaterialishalfthesuccess,tostretch,mustnotbeignored.
Thetensilesheetaremainly08Al,08F,08,10,15,20,ofwhichthelargestamountofsteel,08steel,dividedintoboilingsteelandsteelrimmedsteel,lowprice,goodsurfacequality,butmoreserioussegregation,thestrainagingtendencyisnottobeusedforstampingtheappearanceofhighperformancerequirementsmorestringentrequirementsofspareparts,steelisgood,butthepriceishighperformanceuniform,representativegradesforaluminiumkilledsteel08Al.
SPCC-SDsteelhasbeenusedinforeignsteel,anditstensilepropertiesarebetterthan08Al.
Experience1:
whenthecustomer'
smaterialrequirementsarenotverydemanding,andrepeatedtestingfailedtomeettherequirements,youcanchangeamaterialtotryagain.
2.determinetheblanksize:
Stretchingandrotatingpartsofblankdiameterofsimpleshapeinconstanttensilethininthickness,despitethechanges,butthebasicandoriginalthicknessisveryclose,canaccordingtotheblankareaandthedrawingarea(iftrimmingplustrimmingallowance)equaltocalculate.
However,theshapeandprocessofdrawingpartsaremorecomplex,andsometimestheyarethinnerandstretched.Althoughtherearemanythree-dimensionalsoftwarewhichcanbeusedforunfoldingcalculation,theaccuracycannotbe100%.
Solution:
asample.
Athingtobeproducedthroughseveralprocesses,thefirststepistheblankingprocess.Firstofall,tostartthecalculationofmaterials,blankshapeandsizeofageneralunderstanding,inordertodeterminetheoverallsizeofblankingdie.Afterthediedesignisfinished,donotprocessthepunchdiesizeoftheblankingdie.First,weusewirecuttingtoprocesstheblank(whentheblankislarger,themillingmachinecanbeusedformillingandthenclampit),andthen,afterrepeatedexperimentsofthesubsequentdrawingprocess,wefinallydeterminetheblanksize,andthenprocesstheconcaveandconvexdieoftheblankingdie.
Experience2:
invertedprocess,trydrawingdie,blankingedgedimensionsaftermachiningblanks,half.
3.tensilecoefficientm
Thecoefficientoftensionisoneofthemaintechnologicalparametersintheprocessofdrawing.Itisusuallyusedtodeterminetheorderandfrequencyofthedrawing.
Therearemanyfactorsthataffectthetensilecoefficientm,includingmaterialproperties,relativethicknessofthematerial,tensilemode(whetherthereisblankholder),stretchingtimes,tensilespeed,filletradius,lubricationandsoon.
ThecalculationandselectionprinciplesonstretchingcoefficientmisintroducedallkindsofstampingHandbook,acalculation,look-uptable,calculationofmanymethods,theauspiciousandauspicious,Ialsoaccordingtothebook,thereisnofreshstuff,please.
Experience3:
therelativethicknessofthematerial,tensilemode(referstowhetherthereisnopressurering),thenumberoftimesisnotgoodtorepairtheadjustmentofthemold,mustbecareful!
ThebestchoiceinthetensilecoefficientofM,tofindacolleagueonceagain.
4.applygreaseonthedieorcoverthefilmwithafilmbag.
Experience4:
whenatensilefractureoccurs,greasethedie(notonthepunch).Theworkpieceiscoveredwitha0.013--0.018mmplasticfilmoverthedie
5.workpieceheattreatment
Duringthestretchingprocess,theworkpieceduetocoldplasticdeformation,thecoldworkhardening,theplasticdeformationresistancedecreased,andhardnessincreased,plusthemolddesignisnotreasonable,theneedforintermediateannealing,tosoftenthemetalrecovery,plastic.
Note:
inthegeneralprocess,intermediateannealingisnotnecessary,afterall,toincreasecosts,toincreasetheprocessandincreasethechoiceofannealing,withcaution!
Annealinggenerallyadoptslowtemperatureannealing,thatis,recrystallizationannealing.
Annealingshouldpayattentiontotwopoints:
carbonremovalandoxidation.Here'
sthemainstoryaboutoxidation.Oxidationoftheworkpieceafteroxidation,theharmhastwo:
theeffectivethicknessoftheworkpiecethinning,increasingmoldwear.
Whenthecompanydoesnothavetheconditions,thegeneraluseofordinaryannealing,inordertoreducetheoxidationoftheskin,annealingasmuchaspossibletofillthefurnace,Ialsousedthesoilapproach:
1.workwithothersmallworkpieceloading(premise:
theannealingprocessparametersshouldbeconsistent)
2.theworkpieceisinstalledinthetinweldingsealingfurnace.Inordertoremovetheoxideskin,afterannealing,accordingtothesituationofpicklingtreatment.
Whenthecompanyconditionisavailable,thenitrogenfurnacecanbeadoptedtoanneal,thatis,brightannealing.Withoutlooking,almostthesamecolorasbeforeannealing.
Experience5:
todealwithcoldworkhardeningofstrongmetalorcrackinthetestdie,andnootherway,increasetheintermediateannealingprocess.
6.what'
stheaddedpoint?
:
1.,thesizeoftheproductdrawingsshouldbemarkedonthesideasfaraspossible,tomakesurethattheexternalsizeorsizeofthecavity,andcannotbemarkedatbothinsideandoutsidethesize.Thedrawingsprovidedbyothersshouldbecommunicatedwiththemandunified,
Whenyoucan'
tunify,youshouldknowtheassemblyrelationshipbetweentheworkpieceandotherparts.
2.,thelastprocess,theworkpiecesizeintheouter,tothemaindie,thegaptoreducethesizeofthepunchtoobtain;
workpiecesize,includingthemainpunch,thegaptoincreasethesizeofthedietoobtain;
3.,thefilletradiusoftheconcaveconvexdiecanbeusedasmuchaspossibleinthedesign,soastobringconveniencetothesubsequentdierepair.
4.,todeterminethecauseoftheworkpiecetensioncanbereferredto:
Thecracksduetopoormaterialqualityaremostlyserratedorirregularshapes,andthecracksduetotheprocessandmoldaregenerall
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