tooling vocabulary.docx
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tooling vocabulary.docx
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toolingvocabulary
RunnerSystem
Inthischapter,youwilllearnaboutthefunctions,characteristics,andshapesofthesprue,runner,andgate.
Themoltenplasticinjectedfromtheinjectornozzlewillgothroughasprue(spruebush),arunner,andagateandfillupinthecavity.
Asthetemperatureofmoltenplasticisloweredwhilegoingthroughthesprueandrunner,theviscositywillrise;therefore,theviscosityisloweredbyshearheatgeneratedwhengoingthroughthegatetofillthecavity.
Sprue:
Asprueisachannelthroughwhichtotransfermoltenplasticinjectedfromthenozzleoftheinjectorintothemold.Itisapartofspruebush,whichisaseparatepartfromthemold.
Runner:
Arunnerisachannelthatguidesmoltenplasticintothecavityofamold.
Gate:
Agateisanentrancethroughwhichmoltenplasticentersthecavity.
Thesprue,therunner,andthegatewillbediscardedafterapartiscomplete.However,therunnerandthegateareimportantitemsthataffectthequalityorthecostofparts.
Gate
Thegateiscategorizedintorestrictivegate,whichnarrowstheentrance,andnonrestrictivegate,whichdoesnotnarrowtheentrance.
Thegatehasthefollowingfunctions:
∙Restrictstheflowandthedirectionofmoltenplastic.
∙Simplifiescuttingofarunnerandmoldingstosimplifyfinishingofparts.
∙Quicklycoolsandsolidifiestoavoidbackflowaftermoltenplastichasfilledupinthecavity.
RestrictiveGate
Arestrictivegatehasanarrowentrancetothecavitytorestricttheamountofmoltenplasticinordertoimprovefillinginthecavity.
Therestrictivegatehasthefollowingcharacteristics.
oGeneratesshearheatbygoingthroughthenarrowgate,raisingthetemperatureofmoltenplasticandimprovingthefillinginthecavity.
oReducesresidualstress,andthusreducespartdefectsuchaswarp.
oAsthecoolingsolidificationtimeisshortened,moldingcycleisalsoshortened.
oAsthegatetraceisless,itispossibletocompletefinishingprocessinashorttime.
Therestrictivegatehasthefollowingtypes.
SideGate
SubmarineGate
丂丂(TunnelGate)
Themostcommongate.
Puttothesideofparts.
Thegatetracewillbeleft.
Oftenusedforthestructurewithmorethantwocavities.
Thegatewillbeautomaticallycutoffduringmoldopening.
Thepositionisflexible(front,side,orbackofparts).
Thegateneedstobethoughtaboutnottobeleftinsidethecavity.
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窗体底部
PinPointGate
FanGate
Suitableformoldingmultipleparts.
Thepositionisrelativelyflexible.
Thestructureiscomplicatedduetothreeplatemethodofdie.
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Suitableforlargeandflatplateparts.
Finishingisdifficultandcostishighduetothewidegate.
Thegatetracewillbeleft.
FilmGate
ValveGate
Suitableforthinplateparts.
Finishingisdifficultandcostishighduetothewidegate.
Thegatetracewillbeleft.
Thevalveofthegateopensthegateaccordingtoinjectiontiming.
Sprueandrunnerwillnotbedischargedduetohotrunnermethod.
Puttoeitherthefrontorthebacksurfaceofparts.
NonrestrictiveGate
Anonrestrictivegateinvolvesamethodinwhichmoltenplasticfillsupinthecavitydirectlyfromthesprue.
Thenonrestrictivegatehasthefollowingcharacteristics.
oReducesthelossofinjectingpressureduetodirectcavityfillingfromthesprue.
oLessmoldingmaterialbecausethereisnorunner.
oThesimplemoldstructurereducethecostandproducesamoldwithlesstrouble.
oItislikelythatresidualstressisgeneratedandpartshavecrack.
Thenonrestrictivegatehasthefollowingtype.
DirectGate
Thesprueplaystheroleasgate.
Putonthefrontorbacksideofparts.
Thegatetracewillbeleft.
DeterminingGatePosition
Point1
Setagatepositionwheremoltenplasticfinishedfillingupineachcavitysimultaneously.Sameasmultiplepointsgate.
Point2
Basicallysetagatepositiontothethickestareaofapart.Thiscanavoidsinkmarksduetomoldshrinkage.
Point3
Setagatepositiontoanunremarkableareaofpartorwherefinishingprocesscanbeeasilydone.
Point4
Avoidinjectingfromthedirectionwheretheairinthecavityorthegasgeneratedfrommoltenplasticisinclinedtoaccumulate.
Point5
Fillupmoltenplasticusingthewallsurfaceinordernottogeneratejetting.
Undercutreferstotheconvexorconcaveareaofpart.Whenremovingthepartfromthemold,youneedsomedevicesothatthepartofthemoldwhichcontactstotheundercutcanbemovedtoremovethepartfromthemoldsincethepartwillnotberemovabledirectlywithoutthedevice.
ThisprocessiscalledUndercutprocess.
Undercutprocessusesdifferentmethodsdependinguponwhethertheundercutisoutsideorinsidethepart.
Herearesomeexamplesofpartswithundercut.
Push-pin
Gripofadriver
Gripofacup
Now,let'slearnaboutexternalslidecoremethod,internalslidemethod,andhydrauliccylindermethodofundercutprocess.
ExternalSlideCoreMethod
Theexternalslidecoremethodisusuallyusedfortheprocessofouterundercut.
Workingalongwiththeopen/closemovementofamold,thismethodslidestheslidecoretoprocesstheundercut.
Thehydrauliccylindermethodisalsoavailable,whichwillbeexplainedindetaillater
SlideCoreBodyUnit
Theportionwheretheundercutprocessisperformedlinkedalongwiththemovementofmoldopening.Theamountofmovementoftheslidecoreandtheangleandthelengthoftheangularpinarekeyfactorstothisunit.
Thelockingblockinstalledtothecavityplatereceivesthepressurefromtheinjectionwhenclosingthemold.Uponopeningofthemold,theslidecoremovesbackwardbytheforcefromtheangularpinandthespring,thusreleasingthepart.
Astheholewillbemisalignedandtheangularpinwillnotbeinsertediftheslidecoremovestoofarbackward,acorestopblockneedstobeinstalled.
Thiscorrelationisillustratedbelow.
(Clickeachnameinthefiguretodisplaythedescription.)
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窗体底部
Thereliefdistanceandthetiltangleoftheangularpinareasfollows:
S:
Undercutamount
S1:
Slidestrokeamount
:
Tiltangleofslidecore
:
Tiltangleofangularpin
S1=S+5mmup
=
+(2
-5
)
20
Inordertopreventtheslidecoreandthelokingblockfrominterveningwitheachotherinmoldopeningandclosing,makethetiltangleoftheangularpinsmallerthanthatofthelockingblock.
Also,agapof0.5mmisaddedtotheholeforangularpinforerrorsoccurringatprocessing.
PushBackSpring
Themasswhentheslidecoreisslidingvariesdependingonthedirectionofsliding.
Supposeyouinstalla5kgslidecoreonthesideparalleltotheground.Howlongshouldthespringbe?
Thestrokeis20mm.
D:
Springdiameter
L:
Springfreelength(seeacatalogbyeachmanufacturer)
E:
Springcloselength(seeacatalogbyeachmanufacturer)
F:
Stroke
G:
Lengthofshrinkagebyslideweight
K:
Springconstant(seeacatalogbyeachmanufacturer)
W:
Slideweight
Ifusinglightload[K=0.6kgf/mm]forspring:
Springconstant(K)
Freelength(L)
Max.deflection(F+G)
Outerdiameter(D)
Usagecount
0.6kg/mm
65mm
32.5mm
16mm
350,000times
Tofigureouttheslidemass,itis1.5timestheweightoftheslidecore:
W=5*1.5=7.5kg
Asthelengthofshrinkageduetotheweightoftheslidemassis:
G=W/K:
G=7.5/0.6=12.5mm
Asthefreelengthofthespringis:
L=E+F+G:
L=32.5+20+12.5=65.Referringtothecatalog,
UsethespringwithL=65.
AnswerD=16L=65mm
CorePlate/CavityPlate
Asteeldevicetomoldamoldingmaterialintoacertainshape.Thesectionthatisengagedinopening/closingmovementiscalledacoreplate,andthesectionthatisnotiscalledacavityplate.Generally,thefrontsideofapartisacavityplateandtherearsideisacoreplate.
Thecoreplateleavesatraceonapart,becauseithasanejectorpintopushthepart.
Thecavityplatehasaspruebush,whichistheentranceformoltenplastic.
LockingBlock
Ablocktopushaslidecorethatisejectedbackbyinjectionpressure.
AngleofAngularPinandAngleofAngledSideofLockingBlock
Angleofangularpin:
Angleofsideoflockingblock:
(1)If>:
Iftheangleofanangularpinislargerthantheangledsideofalockingpin,thetiltedsidesofaslidecoreandthelockingblockmaycollidewitheachother,possiblydamagingthemold.
(2)If=:
Iftheangleofanangularpinandatiltangleofalockingblockareequal,theslidecorecannotbelowered,sinceitispusheddownbyaspring,whichputsthelockingblockovertheslidecorefortheclearanceoftheangledholeoftheslidecore.
(3)If<:
Sincetheangledsidesoftheslidecoreandthelockingblocktoucheachotheronlywhenthemoldiscompletelyclosed,themovementissmooth.
From
(1),
(2),and(3),theangleoftheangularpinmustbesmallerthantheangleoftheside.Thenormalangleoftheangularpinis12-25degree,andtheangleofthepartingsideisbasicallylargerthanthepinangle.
CoreStopBlock
Apartthatdeterminesthepositionwhereaslidecoreretreatswhenopeningthemold.
Inadditiontothecorestopblock,aballplunger,areturnspring,orastoppincanalsobeused.
SlideCore
Apartthatslidesinwarduponopeningandclosingofthemold.
Itworksontheundercutprocessalongwithmoldopening/closingmovementtomoldtheundercutofapart.
Thelargertheundercutbecomes,th
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