南通大學(xué)畢業(yè)設(shè)計(論文)38ThepressurecastingTheessencethatthepressureiscast(abbreviatedasdiecasting)isunderhigh-pressurefunction,makeliquidstateorhalfliquidmetalfillandpigeonholecastingmouldtypeinordertohigherspeed,andandsolidifybutthemethodofobtainingthecastinginthepressureshaping.First.DiecastingcharacteristicHighpressureandfillingwithandpressingthecastingmouldtwomajorcharacteristicsthatarediecastingatahighspeed.ItcommonlyusedtoisitisittooddtenthousandkPa,evenisupto2*105kPafromseveralthousandpressingtopenetratetopress.Filledwiththespeedandmadeanappointmentin100m/s,canevenreachabove100m/satsometime.Filledwithtimeveryshort,generallywithintherangeof0.01.2s.Comparedwithothercastingmethods,therearethreefollowingrespectsadvantagesindiecasting:1.TheproductsareofhighqualityThesizeofthecastingishighinprecision,generallyequivalentto6grades,evencanbeupto4grades；Surfacesmoothfinishisgood,generallyequivalentto5grades；Theintensityandhardnessarerelativelyhigh,theintensityisgenerallycastandimprovedby250%morethanthesandmould,butthecoefficientofelongationisreducedbyabout70%；Thesizeissteady,theinterchangeabilityisgood；Thincomplicatedcastingofwallofdiecasting.Forexample,theminimumwallofdiecastingofzincalloyisthick南通大學(xué)畢業(yè)設(shè)計(論文)39canreach0.3mmatpresent；Thealuminiumalloycastingcanreach0.5mm；Itis0.7mmtocastouttheapertureminimumly；Minimumpitchis0.75mm.2.ProductionefficiencyishighMachineproductivityhigh,suchasdomesticJ3typehorizontalcoldemptydiecastingmachine8hoursonaveragebut600-70timesofdiecasting,small-scalehotlaboratorycavediecastingmachineequallyeveryeighthoursbutdiecasting3000000；Itislonge-livedtopressthecastingmould,onepairpressescastingmould,theclockalloyofdiecasting,thelife-spancanbeuptohundredsofthousandstimes,verytouptoamilliontimes；Easytorealizemechanizingandautomizing.3.TheeconomicresultisfineBecausethediecastingisaccurateinsize,theformissuffusedwiththeadvantagesuchasbeingbrightandclean.Generallynolongercarryonmachiningandusedirectly,ortheprocessingamountisverysmall,sohasnotonlyimprovethemetalutilizationratiobutalsoreducedalargenumberofprocessingequipmentandman-hour；Thepriceofthecastingiseasy；Canadoptandmakediecastingupwithothermetalornonmetallicmaterials.Assembleman-hoursavemetalalsosparingly.Therearealotofadvantagesinthoughdiecasting,buttherearesomeshortcomings,tobesolved.Forinstance:1)Becauseoneofspeedsishighintheliquidmetalfillingwithtypeatthetimeofdiecasting,theflowstateisunstable,so南通大學(xué)畢業(yè)設(shè)計(論文)40adoptandgenerallypressthecastingmethod,thecastingisapttoproducetheairvent,notCanheat-treat；2)Totheconcaveandcomplicatedcasting,diecastingiscomparativelydifficult；3)Highpointalloy(suchasthecopper,ferrousmetal),itisrelativelylowtopressthelife-spanofcastingmould；4)Shouldnotproduceinbatchessmall,itiswithhighcoststhatitsmainreasonpigeonholesthecastingmouldandismade,theproductionefficiencyofdiecastingmachineishigh,produceinbatchesuneconomicallysmall.Second.TherangeofapplicationofdiecastinganddevelopmenttrendDiecastingisoneofthemostadvancedmetalshapingmethods,realizinglackingthesmearmetal,withouteffectivewayofsmearmetal,itisverywidetouse,developquickly.Presszinc,aluminium,Vandcopperthatthecastalloydoesnotconfinetothenonferrousmetalsagainatpresent,andexpandandusedforpressingthecastingironandcastingsteelonegradually.Sizeandweightofthediecasting,dependonthepowerofthediecastingmachine.Becausethepowerofdiecastingmachineisincreasingconstantly,theshapemeasurementofthecastingcanbefromseveralmm.to1-2m；Weightcanbefromseveralgramstoseveraldozenkilograms.Butthediameterofdiecastingis2mabroad,weightisaaluminiumcastingof50kg.Diecastingconfine南通大學(xué)畢業(yè)設(shè)計(論文)41autoindustryandinstrumentindustrytonolongertoo,expandothereachindustrialdepartmenttoprogressively,forinstancedozensoftrades,suchasagriculturalmachinery,machinetoolindustry,electronicsindustry,nationaldefenseindustry,computer,medicalequipment,clockandwatch,cameraandhaberdasheryandhardwa