中英文翻译冲压成形的特点与板材冲压成形性能.docx

中英文翻译冲压成形的特点与板材冲压成形性能.docx

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中英文翻译冲压成形的特点与板材冲压成形性能

CharacteristicsofStampingandPropertiesof

SheetMetalForming

1．overview

Stampingisakindofplasticformingprocessinwhichapartisproducedbymeansoftheplasticformingthematerialundertheactionofadie.Stampingisusuallycarriedoutundercoldstate,soitisalsocalledstamping.Heatstampingisusedonlywhentheblankthicknessisgreaterthan8~100mm.Theblankmaterialforstampingisusuallyintheformofsheetorstrip,andthereforeitisalsocalledsheetmetalforming.Somenon-metalsheets（suchasplywood,micasheet,asbestos,leather）canalsobeformedbystamping.

Stampingiswidelyusedinvariousfieldsofthemetalworkingindustry,anditplaysacrucialroleintheindustriesformanufacturingautomobiles,instruments,militarypartsandhouseholdelectricalappliances,etc.

Theprocess,equipmentanddiearethethreefoundationalproblemsthatneededtobestudiedinstamping.

Thecharacteristicsofthesheetmetalformingareasfollows:

（1）Highmaterialutilization

（2）Capacitytoproducethin-walledpartsofcomplexshape.

（3）Goodinterchangeabilitybetweenstampingpartsduetoprecisioninshape

anddimension.

（4）Partswithlightweight,high-strengthandfinerigiditycanbeobtained.

（5）Highproductivity,easytooperateandtorealizemechanizationandautomatization.

Themanufactureofthestampingdieiscostly,andthereforeitonlyfitstomassproduction.Forthemanufactureofproductsinsmallbatchandrichvariety,thesimplestampingdieandthenewequipmentsuchasastampingmachiningcenter,areusuallyadoptedtomeetthemarketdemands.

Thematerialsforsheetmetalstampingincludemildsteel,copper,aluminum,magnesiumalloyandhigh-plasticityalloy-steel,etc.

Stampingequipmentincludesplateshearpunchingpress.Theformershearsplateintostripswithadefinitewidth,whichwouldbepressedlater.Thelatercanbeusedbothinshearingandforming.

2．Characteristicsofstampingforming

Therearevariousprocessesofstampingformingwithdifferentworkingpatternsandnames.Buttheseprocessesaresimilartoeachotherinplasticdeformation.Therearefollowingconspicuouscharacteristicsinstamping:

（1）．Theforceperunitareaperpendiculartotheblanksurfaceisnotlargebutisenoughtocausethematerialplasticdeformation.Itismuchlessthantheinnerstressesontheplateplanedirections.Inmostcasesstampingformingcanbetreatedapproximatelyasthatoftheplanestressstatetosimplifyvastlythetheoreticalanalysisandthecalculationoftheprocessparameters.

（2）．Duetothesmallrelativethickness,theanti-instabilitycapabilityoftheblankisweakundercompressivestress.Asaresult,thestampingprocessisdifficulttoproceedsuccessfullywithoutusingtheanti-instabilitydevice（suchasblankholder）.Thereforethevarietiesofthestampingprocessesdominatedbytensilestressaremorethandominatedbycompressivestress.

（3）．Duringstampingforming,theinnerstressoftheblankisequaltoorsometimeslessthantheyieldstressofthematerial.Inthispoint,thestampingisdifferentfromthebulkforming.Duringstampingforming,theinfluenceofthehydrostaticpressureofthestressstateinthedeformationzonetotheforminglimitandthedeformationresistanceisnotsoimportantastothebulkforming.Insomecircumstances,suchinfluencemaybeneglected.Eveninthecasewhenthisinfluenceshouldbeconsidered,thetreatingmethodisalsodifferentfromthatofbulkforming.

（4）．Instampingforming,therestrainactionofthedietotheblankisnotseversasinthecaseofthebulkforming（suchasdieforging）.Inbulkforming,theconstraintformingisproceededbythediewithexactlythesameshapeofthepart.Whereasinstamping,inmostcases,theblankhasacertaindegreeoffreedom,onlyonesurfaceoftheblankcontactswiththedie.Insomeextracases,suchastheformingoftheblankonthedeformingzonecontactwiththedie.Thedeformationintheseregionsarecausedandcontrolledbythedieapplyinganexternalforcetoitsadjacentarea.

Duetothecharacteristicsofstampingdeformationandmechanicsmentionedabove,thestampingtechniqueisdifferentformthebulkmetalforming:

（1）．Theimportanceorthestrengthandrigidityofthedieinstampingformingislessthanthatinbulkformingbecausetheblankcanbeformedwithoutapplyinglargepressureperunitareaonitssurface.Instead,thetechniquesofthesimpledieandthepneumaticandhydraulicformingaredeveloped.

（2）．Duetotheplanestressorsimplestrainstateincomparisonwithbulkforming,moreresearchondeformationorforceandpowerparametershasbeendone.Stampingformingcanbeperformedbymorereasonablescientificmethods.Basedontherealtimemeasurementandanalysisonthesheetmetalpropertiesandstampingparameters,bymeansofcomputerandsomemoderntestingapparatus,researchontheintellectualizedcontrolofstampingprocessisalsoinproceeding.

（3）．Itisshownthatthereisacloserelationshipbetweenstampingformingandrawmaterial.Theresearchonthepropertiesofthestampingforming,thatis,formingabilityandshapestability,hasbecomeakeypointinstampingtechnologydevelopment,butalsoenhancesthemanufacturingtechniqueofironandsteelindustry,andprovidesareliablefoundationforincreasingsheetmetalquality.

3．Categoriesofstampingforming

Manydeformationprocessescanbedonebystamping,thebasicprocessesofthestampingcanbedividedintotwokinds:

cuttingandforming.

Cuttingisashearingprocessthatonepartoftheblankiscutfromtheother.Itmainlyincludesblanking,punching,trimming,partingandshaving,wherepunchingandblankingarethemostwidelyused.Formingisaprocessthatonepartoftheblankhassomedisplacementfromtheother.Itmainlyincludesdeepdrawing,bending,localforming,bulging,flanging,necking,sizingandspinning.

Insubstance,stampingformingissuchthattheplasticdeformationoccursinthedeformationzoneofthestampingblankcausedbytheexternalforce.Thestressstateanddeformationcharacteristicofthedeformationzonearethebasicfactorstodecidethepropertiesofthestampingforming.Basedonthestressstateanddeformationcharacteristicsofthedeformationzone,theformingmethodscanbedividedintoseveralcategorieswiththesameformingpropertiesandbestudiedsystematically.

Thedeformationzoneinalmostalltypesofstampingformingisintheplanestressstate.Usuallythereisnoforceoronlysmallforceappliedontheblanksurface.Whenisassumedthatthestressperpendiculartotheblanksurfaceequalstozero,twoprincipalstressesperpendiculartoeachotherandactontheblanksurfaceproducetheplasticdeformationofthematerial.Duetothesmallthicknessoftheblank,itisassumedapproximatelythetwoprincipalstressesdistributeuniformlyalongthethicknessdirection.Basedonthisanalysis,thestressstateandthedeformationcharacteristicsofthedeformationzoneinallkindsofstampingformingcanbedenotedbythepointsinthecoordinatesoftheplaneprincipalstressesandthecoordinatesofthecorrespondingplaneprincipalstrains.

4．Rawmaterialsforstampingforming

Therearealotofrawmaterialsusedinstampingforming,andthepropertiesofthesematerialsmayhavelargedifference.Thestampingformingcanbesucceededonlybydeterminingthestampingmethod,theformingparametersandthediestructuresaccordingtothepropertiesandcharacteristicsoftherawmaterials.Thedeformationoftheblankduringstampingforminghasbeeninvestigatedquitethoroughly.Therelationshipsbetweenthematerialpropertiesdecidedbythechemistrycomponentandstructureofthematerialandthestampingforminghasbeenestablishedclearly.Notonlythepropermaterialcanbeselectedbasedontheworkingconditionandusagedemand,butalsothenewmaterialcanbedevelopedaccordingtothedemandsoftheblankpropertiesduringprocessingthestampingpart.Thisisanimportantdomaininstampingformingresearch.Theresearchonthematerialpropertiesforstampingformingisasfollows:

（1）．Definitionofthestampingpropertyofthematerial.

（2）．Methodtojudgethestampingpropertyofthematerial,findparameterstoexpressthedefinitelymaterialpropertyofthestampingforming,establishtherelationshipbetweenthepropertyparametersandthepracticalstampingforming,andinvestigatethetestingmethodsofthepropertyparameters.

（3）．Establishtherelationshipamongthechemicalcomponent,structure,manufacturingprocessandstampingproperty.

Therawmaterialsforstampingformingmainlyincludevariousmetalsandnonmetalplate.Sheetmetalincludesbothferrousandnonferrousmetals.Althoughalotofsheetmetalsareusedinstampingforming,themostwidelyusedmaterialsaresteel,stainlesssteel,aluminumalloyandvariouscompositemetalplates.

5．Stampingformingpropertyofsheetmetalanditsassessingmethod

Thestampingformingpropertyofthesheetmetalistheadaptationcapabilityofthesheetmetaltostampingforming.Ithascrucialmeaningtotheinvestigationofthestampingformingpropertyofthesheetmetal.Inordertoproducestampingformingpartswithmostscientific,economicandrationalstampingformingprocessandformingparameters,itisnecessarytounderstandclearlythepropertiesofthesheetmetal,soastoutilizethepotentialofthesheetmetalfullyintheproduction.Ontheotherhand,toselectplatematerialaccuratelyandrationallyinaccordancewiththecharacteristicsoftheshapeanddimensionofthestampingformingpartanditsformingtechniqueisalsonecessarysothata