外企结构工程师资料文档格式.docx

外企结构工程师资料文档格式.docx

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oUsingamaterialdifferentfromthatofthemoldimprovesabrasionresistanceormakestemperaturecontroleasier.

oItisdifficulttodirectlymachineamoldwhencomplicatedshapesormultipleshapesarealigned,whereasattachinganinsertasaseparatepartmakestheprocesseasier.

oItispossibletochangethematerialofthepartthatissubjecttodamageduetorepeatedmoldingwithaspecialmaterialorreplaceonlythedamagedpart.

Aninsertattachedtothecavitysideiscalledacavityinsert.Aninsertthatisattachedtothecoresideiscalledacoreinsert.

Thefollowingfactorsdeterminewhetheraninsertisused.

MoldCondition

MoldingCondition

MoldMaterial

Singlepart

Multiplepart

SpecialShape

S55C

Integral

Coreinsert

Coreinsert,Cavityinsert

SpecialSteel

Theshapeofapartdetermineswhetheraninsertisattachedtothecavity,thecore,orboth.

Also,theinsertmethodisusedtoprocessthecavityandthecorewithspecialmaterials,dependingonthemoldingmaterial.

TypesofInsert

AnInsertiscategorizedintothefollowingtypes.

∙Flangeinsert

Iftheshapeofthepartisround,aflangeinsertisused.Theinsertdoesnotneedabaffle,soonlyaflangeisneededtopreventaninsertfromlifting.

Aroundshapeiseasytoprocesswhenmakinganinsertoramold.

Also,aflangeisattachedonlytothelongsidewhenusingasquareflangeinsert.

Asinthefigure,ifH>

L.,attachaflangetotheLdirection,andifH<

L,totheHdirection.

∙PocketInsert

Apocketinsertisgenerallyusedwhentheshapeofthepartissquare.

Apocketinsertisattachedtothemoldbyanattachingbolt,asshownbelow.

MakingInserts

Whenmakinganinsertoramold,becarefulwiththeaccuracyofmeasurementsothattheinsertandthemoldcanbeattachedwithoutagap.

Ifthemeasurementisnotaccurate,aninsertcannotbeattachedtoamold,oraburrmayresultduetothebiggap,andthepartwillnotlookgood.

Attachaninsertandamoldbyprocessingasfollows.

Foraflangeinsert:

Astheinsertismountedthroughthemold,chamfersareappliedtothemoldsidewhosecornerwillbeconvex.

Forapocketinsert:

Astheinsertismountedinthemold,chamfersareappliedtothemoldsidewhosecornerwillbeconvex.

Whenmakinganinsertoramold,chamfersareappliedtoitscorners.

ThecornerscannotbeprocessedatarightangleduetotheedgeRofcutwareorreliefofcutware,evenwhenaninsertoramoldismadeaccuratelyasmeasured.Ifaninsertisattachedtoamoldwithoutchamfering,thecornerwillinterfereandpreventtheinsertfrombeingattachedattheproperposition.

Also,anexcessivegapbetweenaninsertandamoldwillcausepartdefects.Therefore,besuretofulfillthematchingrequirement（positionaltoleranceofholeandaxis）thatisregulatedbytheJapaneseIndustrialStandard（JIS）.

Thechartbelowshowsthetypicalmatchingtolerances.

Holetolerance（φD）

Axistolerance（φd）

RegularProcess

H7

h6

PreciseProcess

H6

h5

Inthechartabove,theholetolerance（φD）referstothetoleranceoftheholesize（φD）ofthemoldintheabovefigure,andtheaxistolerance（φd）referstothetoleranceoftheaxissize（φd）oftheinsertintheabovefigure.

Asthematchingtolerancevariesdependingonouterdiameterofholeoraxisortypesofmatching（gapmatching,midpointmatching,ordrawmatching）,refertotheJISreferencechart.

PositionofInsert

Thepositionofaninsertisdeterminedbypartquantityortypeofinsert.

Thepositionsofinsertareasfollows:

Whenaflangeinsertisused:

Process

Theinsertisattacheddirectlytothemold,Boththeinsertandthemoldneedtobemadeprecisely.

Installation

Itiseasytopositiontheinserttoamoldbecausetheinsertismadeprecisely.

Whenapocketinsertisused:

Themoldismadewiththemeasurementofaninsert+arunner.

Evenifthereisanerrorinthemoldmeasurement,themoldiseasilyprocessedbecausearunner（madebyaseparatepart）isusedforadjustment.

Itisdifficulttopositiontheinsertbecauseitisattachedwiththerunnerinsertedin-betweenandameasurementerrorcaneasilyoccur.

Themoldcanbeprocessedeasilybecauseawedgemeasurementisusedtoadjust,evenifthereisanerrorinamoldmeasurement.

Becauseaninsertisattachedsetout,anerrorbyattachmentoccurslessfrequentlyandinsertpositioningiseasy.

CorePlate/CavityPlate

Asteeldevicetomoldamoldingmaterialintoacertainshape.Thesectionthatisengagedinopening/closingmovementiscalledacoreplate,andthesectionthatisnotiscalledacavityplate.Generally,thefrontsideofapartisacavityplateandtherearsideisacoreplate.

Thecoreplateleavesatraceonapart,becauseithasanejectorpintopushthepart.

Thecavityplatehasaspruebush,whichistheentranceformoltenplastic.

Cavity

Thegapgeneratedwhereapartismoldedinthemold.

Itsometimesreferstotheconcavepartofthemoldandusuallyisprocessedonthecavityplate.

Insert（Core）

Apartofamoldtoshapeamoldingmaterial

Itismountedinasquareorroundholeonaretainerplateofamold.

Abrasionresistanceisrequiredforaninsertbecauseitconstantlyreceivesfrictiongeneratedbyheatorflowofmoltenplasticduringmolding,andthus,ahighqualitymaterialisusedforaninsert.Moldingismadeeasierforacomplicatedshapeortherepetitionofthesameshapewithinsertswhicharesmallandlight.

Theinsertinstalledonthecavitysideiscalledacavityinsert,andtheoneinstalledonthecoresideiscalledacoreinsert.Thepartshapeandmaterialdetermineswhichinserttouse.

Runner

Achannelthroughwhichmoltenplasticisguidedfromthespruebushintothecavityofthemold.Itssizeorshapeisdeterminedbythetypeofmoldingmaterial.

Alargerunnerallowsbetterflowofthemoldingmaterial;

however,coolingtakeslonger.Thus,arunnerisnormallymadesmallerthanthesectionofapartandgraduallymadebiggerwhiletesting.Inanycase,arunnershouldbebasicallysmallerthanthethickestareaofthepart.

CoreStopBlock

Apartthatdeterminesthepositionwhereaslidecoreretreatswhenopeningthemold.

Inadditiontothecorestopblock,aballplunger,areturnspring,orastoppincanalsobeused.

LockingBlock

Ablocktopushaslidecorethatisejectedbackbyinjectionpressure.

AngleofAngularPinandAngleofAngledSideofLockingBlock

Angleofangularpin:

α

Angleofsideoflockingblock:

β

（1）Ifα>

β:

Iftheangleofanangularpinislargerthantheangledsideofalockingpin,thetiltedsidesofaslidecoreandthelockingblockmaycollidewitheachother,possiblydamagingthemold.

（2）Ifα=β:

Iftheangleofanangularpinandatiltangleofalockingblockareequal,theslidecorecannotbelowered,sinceitispusheddownbyaspring,whichputsthelockingblockovertheslidecorefortheclearanceoftheangledholeoftheslidecore.

（3）Ifα<

Sincetheangledsidesoftheslidecoreandthelockingblocktoucheachotheronlywhenthemoldiscompletelyclosed,themovementissmooth.

From

（1）,

（2）,and（3）,theangleoftheangularpinmustbesmallerthantheangleoftheside.Thenormalangleoftheangularpinis12-25degree,andtheangleofthepartingsideisbasicallylargerthanthepinangle.

AngularPins

Aangledpinusedtoslideaslidecore.

Thetiltangleforanangularpinshouldbeunder25degreesatthemaximum.

SlideCore

Apartthatslidesinwarduponopeningandclosingofthemold.

Itworksontheundercutprocessalongwithmoldopening/closingmovementtomoldtheundercutofapart.

Thelargertheundercutbecomes,thelongeranangularpinneedstobeandthemorethemovementoftheslidecorewillbe;

thereforeitmaynotbeeasilyused.

Theslidecoremovestoavoidretreatingbyinjectionpressureatthelockingblockwhenclosingthemoldandatthecorestopblockwhenopeningthemold.Inbetweenthem,anangularpincontrolsthemovementoftheslidecore.

CorePushBackSpring

Apartusedtoholddownaslidecorewhenamoldisopen.

Withoutthis,theslidecoremaybeoutofalignmentwhenthemoldisopen,andalsoanangularpinmaynotgointotheangledholewhenclosingthemold.

Itischangeddependingontheslidingdirectionoftheslidecore,suchasup,down,orhorizontal.

Undercut

Ashapethatpreventsapartfrombeingremovedintheopeningdirectionofam