注射模具及冲压模具-毕业论文外文翻译

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1、THEINGECTIONMOLDANDPUNCHINGDIEMoldordiearethecommontermsusedtodescribethetoolingusedtoproduceplasticpartsinmolding.Traditionally,moldshavebeenexpensivetomanufacture.Theywereusuallyonlyusedinmassproductionwherethousandsofpartswerebeingproduced.Moldsaretypic

2、allyconstructedfromhardenedsteel,pre-hardenedsteel,aluminium,and/orberyllium-copperalloy.Thechoiceofmaterialtobuildamoldfromisprimarilyoneofeconomics,steelmoldsgenerallycostmoretoconstruct,buttheirlongerlifespanwilloffsetthehigherinitialcostoverahighernumb

3、erofpartsmadebeforewearingout.Pre-hardenedsteelmoldsarelesswearresistantandareusedforlowervolumerequirementsorlargercomponents.Thesteelhardnessistypically38-45ontheRockwell-Cscale.Hardenedsteelmoldsareheattreatedaftermachining.Thesearebyfarthesuperiorinter

4、msofwearresistanceandlifespan.Typicalhardnessrangesbetween50and60Rockwell-C(HRC).Aluminiummoldscancostsubstantiallyless,andwhendesignedandmachinedwithmoderncomputerizedequipment,canbeeconomicalformoldingtensorevenhundredsofthousandsofparts.Berylliumcopperi

5、susedinareasofthemoldwhichrequirefastheatremovalorareasthatseethemostshearheatgenerated.ThemoldscanbemanufacturedbyeitherCNCmachiningorbyusingElectricalDischargeMachiningprocesses.Themoldconsistsoftwoprimarycomponents,theinjectionmoldandpunchingdie.Plastic

6、resinentersthemoldthroughasprueintheinjectionmold,thespruebushingistosealtightlyagainstthenozzleoftheinjectionbarrelofthemoldingmachineandtoallowmoltenplastictoflowfromthebarrelintothemold,alsoknownascavityThespruebushingdirectsthemoltenplastictothecavityi

7、magesthroughchannelsthataremachinedintothefacesoftheAandBplates.Thesechannelsallowplastictorunalongthem,sotheyarereferredtoasrunners.Themoltenplasticflowsthroughtherunnerandentersoneormorespecializedgatesandintothecavitygeometrytoformthedesiredpart.Theamou

8、ntofresinrequiredtofillthesprue,runnerandcavitiesofamoldisashot.Trappedairinthemoldcanescapethroughairventsthataregroundintothepartinglineofthemold.Ifthetrappedairisnotallowedtoescape,itiscompressedbythepress