模具专业英语 教学课件 作者 王浩钢 14456第9章.ppt

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1、Lesson9MouldCavitiesandCoresThecavityandcoregivethemoldingitsexternalandinternalshapesrespectively,theimpressionimpartingthewholeoftheformtothemolding.Wethenproceededtoindicatealternativewaysbywhichthecavityandcorecouldbeincorporatedintothemouldandfoundthatthesealter

2、nativesfellundertwomainheadings,namelytheintegermethodandtheinsertmethod.Anothermethodbywhichthecavitycanbeincorporatedisbymeansofsplitinsertsorsplits.IntegercavityandcoreplatesWhenthecavityorcoreismachinedfromalargeplateorblockofsteel,oriscastinonepiece,andusedwitho

3、utbolsteringasoneofthemouldplates,itistermedanintegercavityplateorintegercoreplate.Thisdesignispreferredforsingle-impressionmouldsbecauseofthestrength,smallersizeandlowercostcharacteristics.Itisnotusedasmuchformulti-impressionmouldsasthereareotherfactorssuchasalignme

4、ntwhichmustbetakenintoconsideration.Ofthemanymanufacturingprocessesavailableforpreparingmouldsonlytwoarenormallyusedinthiscase.Theseare(a)adirectmachiningoperationonaroughsteelforgingorblankusingtheconventionalmachinetools,or(b)the‘precision’investmentcastingtechniqu

5、einwhichamasterpatternismadeofthecavityandcore①.Thepatternisthenusedtoprepareacastingofthecavityorcorebyaspecialprocess.A4.25%nickel-chrome-molybdenumsteel(BS970-835M30)isnormallyspecifiedforintegermouldplateswhicharetobemadebythedirectmachiningmethod.Theprecisioninv

6、estmentcastingmethodusuallyutilizesahigh-chromesteel.InsertscavityandcoreFormouldscontainingintricateimpressions,andformulti-impressionmoulds,itisnotsatisfactorytoattempttomachinethecavityandcoreplatesfromsingleblocksofsteelaswithintegermoulds②.Themachiningsequencesa

7、ndoperationwouldbealtogethertoocomplicatedandcostly.Theinsert-bolsterassemblymethodisthereforeusedinstead.Themethodconsistsinmachiningtheimpressionoutofsmallblocksofsteel.Thesesmallblocksofsteelareknown,aftermachining,asinserts,andtheonewhichformsthemalepartistermedt

8、hecoreinsertand,conversely,theonewhichformsthefemalepartthecavityinsert.Thesearetheninsertedandsecurelyfittedintoholesinasubstantia