成型技術FANUC发那科 of Injection Molding GPG1

1,IntroductionofInjectionMolding,KenChangProductionTechnologyCenter,-2-,Content,Whatsinjectionmolding?FactorsToInjectionMoldingQualityInjectionMachineInjectionMoldingCycleRunners,GatesandVentsInjectionMoldIntroductionPartsDesignGeneralMoldingDefects,-3-,Whatsinjectionmolding?,Aprocessthatutilizesmeltedplasticsinjectedintosteeloraluminummoldswhichultimatelyresultinfinishedproductionparts.Amoldingprocedurewherebyaheat-softenedplasticmaterialisforcedfromacylinderintoarelativelycoolcavitygivingthearticlethedesiredshape.Methodofformingaplastictothedesiredshapebyforcingtheheatsoftenedplasticintoarelativelycoolcavityunderpressure.Processofturningplasticresinintopartsthatrangefromverysimpletohighlycomplexinshape.Themoltenresinisfedunderpressureintoamoldwhereitsolidifiesintoshapewhenitcomesintocontactwiththecoldwallofthemoldandthenisremoved.Theinjectionofmoltenmetalorothermaterialunderpressureintomolds.Manufacturingprocesswhereplasticisforcedintoamoldcavityunderpressure.Theprocessofinjectionmoltenplasticresinintothecavityofamoldtooltocreate3Dplasticcomponents.Amanufacturingprocessinwhichaheatedmaterial(thermoplastic)isforcedunderpressureintoawatercooledmold.,-4-,AdvantagesofInjectionMolding,HighproductionratesHightolerancesarerepeatableWiderangeofmaterialscanbeusedLowlaborcostsMinimalscraplossesLittleneedtofinishpartsaftermolding,-5-,DisadvantagesofInjectionMolding,ExpensiveequipmentinvestmentRunningcostsmaybehighPartsmustbedesignedwithmoldingconsideration,-6-,Factorsaffectinginjectionmoldingquality,-7-,PartsQuality,Factorsaffectinginjectionmoldingquality,-8-,SelectionofMoldingMachine,Injectorcapacity:Thecapacityofaninjectorisdeterminedbythemaximumclampingforceandthemaximuminjectionquantity.Clampingforce:Themaximumpressurerequiredtokeepthediefromopeningwhenthemoltenresinisfedintothedie.Injectionquantity:ThemaximuminjectionquantityperinjectionMoldplatearea:Themaximumareaontowhichthediecanproject.Youshouldbeabletomanufactureproductsofnormalqualitywith40-70%ofthemaximumclampingforceand40-70%ofthemaximuminjectionquantity(30-80%forlarge-sizedproducts).Youcanmoldlargerproducts,butitmayhurttheproductstabilityandthelifeofthemoldingmachine.Therefore,itisdesirabletostickwiththeabovepercentages.Therequiredfasteningforcecanbecalculatedbymeansoftherequiredunitinjectionpressureforindividualresinsandtheprojectionareaoftheproduct.,-9-,Machine:InjectionPressSystems,Theinjectionmoldingmachinessupportsystemsincludetheframe,hydraulicsystem,electricalsystem,andcoolingsystem.Thesearethesupportsystemsthathelprunaninjectionmoldingmachine.,-10-,Machine:InjectionUnit,Theinjectionmoldingmachinesinjectionunitincludesthehopper,barrel,screw,non-returnassembly,andnozzle.,-11-,Machine:ClampingUnit,Theinjectionmoldingmachinesclampingunitincludestheclampingsystem,machineejectors,moveableplaten,stationaryplaten,andtiebars.,-12-,Machine:MachineControls,Thedrawinghererepresentsamicroprocessorcontrolledinjectionmoldingmachine.Themachinecontrolsincludethecontrolpanelandthecomputer.,-13-,InjectionMoldingCycle,Thisanimationillustratestheinjectionmoldingcycle.Thefourphasesofaninjectionmoldingcycleare:,-14-,InjectionMoldingCycle,-15-,GeneralSetUpwithRobot,-16-,GeneralSetupw/oRobot,-17-,VerticalSetUpwithRobot,-18-,StepsForInjectionMolding,-19-,IntroductiontoRunners,GatesandVentsRunnerandGateDesign1,Introductiononthebasictypesandfunctionsofrunners,gatesandventsininjectionmolding.Youwillalsoknowabouttheselection,application,andcommonproblemsassociatedwithrunners,gates,andvents,-20-,IntroductiontoRunners,GatesandVentsinjectionmoldingcycle2,Thisdrawingdepictsareciprocatingscrewinjectionmoldingmachine.Plasticresinfromthehopperenterstheextruderscrewandbecomesfluidbytheshearoftherotatingscrewandtheheatingbands.Thescrewadvancesforcingtheplasticizedmaterialintoaclosedmold.Thescrewreturnsandtheprocessisrepeated.,-21-,IntroductiontoRunners,GatesandVentsInjectionMoldingCycle3,Thisdrawingshowsthecrosssectionalviewofaplasticinjectionmoldbase.Thenozzleoftheinjectionmoldingmachineseatsintothespruebushing.Plasticflowsinasequencefromthespruetothepart.Waterlinescooltheplasticmaterial,themoldopens,andthepartandrunnersystemareejected.,-22-,IntroductiontoRunners,GatesandVentsInjectionMoldingCycle4,Thisphotographshowsacompleterunnersystemofaplasticspoon,knife,andforkmold.Shownarethesprue,runners,gates,coldslugwells,aswellasthemoldedparts.,-23-,IntroductiontoRunners,GatesandVentsSprueDefinition5,Thesprueisapassagewayfortheplastictotravelfromthenozzleoftheinjectionmoldingmachinetotherunnerinthemold.Itisround,tapered,andhasanundercutatthelargeend.Thisundercutholdsandseparatesthespruefromthenozzleafterthemoldhasopenedandthesprueandrunnersystemejected,-24-,IntroductiontoRunners,GatesandVentsRunnerDefinition6,Therunneristhepassagewayfortheplastictotravelfromthespruetothegatesofthemoldcavities.Thispictureshowstheplasticflowingthroughthesprueandrunnersystem.,-25-,IntroductiontoRunners,GatesandVentsGateDefinition7,Thegateisarestrictedpassagewayfortheplastictotravelfromtherunnerintothemoldcavity.Thispictureshowstheplasticflowingfromtherunnerintothegate,-26-,IntroductiontoRunners,GatesandVentsCavityDefinition8,Thecavityareaisintheshapeoftheplasticparttobeproduced.Thegraphichereshowsthecompleteflowoftheplasticfromthespruebushingthroughtherunnerandgatesystemsandintothemoldcavitytoformthepart.,-27-,IntroductiontoRunners,GatesandVentsVentDefinition9,Asthemoldcavityisbeingfilledwithplastic,aircanbetrappedandmustbedisplaced.Thisdisplacementisaccomplishedthroughventsalongthepartinglineorthroughejectionpins.Iftheairisnotventedthecompressionofthetrappedairwillcreateenoughheattoburntheplastic.Theanimationhereshowsventingofairandgasesfromthecavityataspotoppositethegate.,-28-,Runners:BalancedHPattenRunnerSystem,ThisdrawingshowsabalancedHpatternrunnersystemusedtomoldfoursquarecolorchips.Thearrowsshowtheplasticflowfromthespruethroughtherunners,gates,andintothecavities.TheadvantagesofthebalancedHpatternwillbecoveredlateroninthisunit.,-29-,Runners:RunnerTypes,Thetwomostcommonrunnertypesinusetodayarethefullroundandthetrapezoidal.Thefullroundstyleisusedmostoften.,-30-,Runners:FullRoundRunner-Style,Thisdrawingrepresentsacrosssectionviewofafullroundrunnermachinedintothepartinglineofamoldbase.Notethathalfoftherunnerisinthetopplateandhalfoftherunnerisinthebottomplate.Therunnerisejectedoutofthemoldbasewiththepart,-31-,Runners:FullRoundRunnerSection,Aplasticskinfreezesagainstthecooledmoldsurfaceandcausesmoltenplastictoflowthroughthecenteroftherunner.Theroundrunnerhastheleastamountoffrictiontoitsvolume,leastpressuredrop,bestflow,andistheeasiestrunnertoejectfromthemold.However,moretimeandskillmatchingtherunnerintobothmoldhalvesisrequired,-32-,Runners:FullRoundRunnerMachining,ThisdrawingrepresentsthemethodusedtomachineonehalfoftheroundrunnerintothemoldsteelThehardballendmillcutteranditsholderarerotatedinthespindleofamillingmachine.Thecuttermarksleftontherunnersurfacemustberemovedbypolishingwithrotaryabrasives.,-33-,Runners:TrapezoidalRunner-Style,Thisdrawingrepresentsacrosssectionofatrapezoidalrunnermachinedintothepartinglineofamoldbase.Notethatalloftherunnerismachinedintooneplate.Therunnerisejectedoutofthemoldbasewiththepart.,-34-,Runners:TrapezoidalRunner-Selection,Aplasticskinfreezesagainstthecooledmoldsurfaceandcausesmoltenplastictoflowthroughthecenteroftherunner.Althoughthetrapezoidalrunneriseasiertomachinesinceitiscutintoonlyoneplate,thisadvantagecanbeoutweighedbythegreaterflowrestriction.Selectionofthisrunnerwouldbefora3platemoldorpassingoveraslidethatwouldnotallowafullroundrunnersystem.,-35-,Gates:SprueGate/DirectGate,Thearrowsonthepicturerepresenttheplasticflowfromthenozzleoftheinjectionmoldingmachinethroughthespruegateandthenradiallytofilltheplatecavity.Thisstyleofgateisusedforalarge,singlecavitymold.Gatingatthecentergivesanevenflow,minimumpressureloss,andeliminatestrappedairandweldlines.Disadvantagesaredegatingandnocoldslugwells.,-36-,Gates:SprueGates/DirectGates,GateCosmeticsFigureAshownheredepictsalargescarleftfromcuttingormachiningthespruegate.Therefore,itisimportanttogateintoanon-cosmeticareaorsurfacethatwillnotaffectthepartfunction.Othercosmeticproblemsarepossibleflowlinesradiatingoutfromthesprue,and/orsinkmarksoppositethesprue.,-37-,Gates:RingGates,PartConfigurationThearrowsonthedrawinghererepresenttheplasticflowfromthefeedrunnerintoandaroundtheperipheryofthelong,hollowtube.Thenitflowsradiallyacrosstheringgateanduniformlydownthelengthofthetube.Thematerialflowseasilyonlong,hollow,cylindricalparts.Ringgatespreventweldmarks,trappedair,orstressconcentrationaroundthegate.,-38-,Gates:RingGates,GateCosmeticsThisdrawingrepresentsthehollowplastictubewiththeringgate/runnersystemremoved.Sinceascarorblemishremainsitisdesirabletogateintoanon-cosmeticornon-functionsurface.Ifthetubeinsidediameterislargeenoughadiscgate(reverseofaringgate)maybeused.Thiswillkeepthegatescaroffoftheoutsidepartsurface.,-39-,Gates:PointGates,PartConfigurationThearrowsonthedrawingshownhererepresenttheplasticflowfromthesprue,runnersystem,pointgate,andintothecupshapecavities.A3platemoldsystemautomaticallydegatesthepartandsprue.The3platemoldseparatestherunnersystem,aswellasthepartfromthecavityside,andejectseverythingfromthemoldbase.Thisdesignrequiresatrapezoidalrunnersystemwithsuckerpinstobreakthegates.,-40-,Gates:PointGates,ResinFillerThesmallcross-sectionalopeningofthepointgatebecomesaproblemwithrespecttoresinfilledplastic.Thisstylegatecouldbeaproblemwithlowviscosity,longfiber,orbeadfilledresins.Thesmallgaterestrictioncouldraisethemelttemperatureandaffectheatsensitiveresins.Ignoringthesefactorscouldresultinhighmoldmaintenance.GateCosmeticsEnlargementAshowsaverysmallscarleftafterthegatepullsfreeofthepart.Onthispartdesignthescarareaislowerthanthehighestsurfacenotaffectingthepartfunction.Somedesignsallowgatingintoaverysmallconcavedishonthepartsurfacetoinsurethatthescarbreakisbelowaflatsurface.,-41-,Gates:EdgeGate1,Theedgegateshownhereisthemostcommonstyleofgate.Thearrowshowstheplasticflowfromtherunner,throughthegate,andintothecavity.Halfontheroundrunnerandallofthegateismachinedintothecavitysideshownhere.,-42-,Gates:EdgeGates,PartConfigurationTheedgegateshownhereisthemostcommonstyleofgatewithmanypartconfigurationsbeingused.Thearrowshowstheplasticflowfromtherunner,throughthegate,andintothecavity.Halfoftheroundrunnerandallofthegateismachinedintothecavitysidehere.Thistypeofgatecanbeeasilyremovedfromthepart.,-43-,Gates:EdgeGates,GateCosmeticsEnlargementAshowsaverysmallscarleftafterthegatehasbeenremoved.Ifaestheticsanddesignfunctionallow,thisgatecanbetornawaybyhand.Ifnot,thepartgatesurfacecanbeimprovedbyhandnipping,orplacingthepartandrunnersystemintoatrimfixture,-44-,Gates:Submarine/TunnelGates,PartConfigurationAdvantagestothegatingmethoddrawnhereareautomaticdegating.Gatingfromthebottomupaidsventing,andgatingintoribs,bosses,andnoshowareasimprovescosmetics.Thepartisshearedfromthegatewhentheejectorpinsforcethepartandrunnersystemoutofthemold.Thetunnelgate/runnermustflexenoughtopopoutofitsrestrictedarea.,-45-,Gates:Submarine/TunnelGates,GateCosmeticsSubmarineortunnelgatesleaveaverysmallgatescaronthepart(Approximately.020to.060indiameter)makingthemhighlydesirable.Inaddition,thesubmarinegatecreatesanopportunitytolocateonanon-cosmeticsurfaces.Bydesign,thescarisshearedclean,automatically.,-46-,Gates:TabGates,PartConfigurationThearrowsonthedrawingrepresenttheplasticflowfromthesprue,runner,edgegate,tab,andintothepartcavity.Thismethodpreventsjettingintothecavityorothersurfaceimperfections.Astrongerpartwillbeobtainedfromthebetterflowpatterninthecavityandstress/strainisleftinthetab.,-47-,Gates:TabGates,GateCosmeticsEnlargementAshowsalargescarleftfromthetabthathasbeenremoved.Thescarcanberemovedbysnippingorbyplacingthepartinatrimfixture.Sinceitisaratherlargescaritisadvisabletolocatethetabonanon-cosmetic/non-functionalarea.Dependinguponpartdesign/functionitmaybepossibletoleavethetab.,-48-,Gates:FanGates,PartConfigurationThearrowsonthedrawinghererepresenttheplasticflowfromthesprue,runner,fangate,andintothepartcavity.Forlargeorthickpartsectionsthefangateprovidesasmoothtransitionfromtherunnertothecavity.Thefangatecanalsobeusedtospreadouttheflowpatternonthinmaterialtohelpminimizethepossibilityofflowlines.,-49-,Gates:FanGates,GateCosmeticsEnlargementAshowsalargescarleftfromthefangatethathasbeenremoved.Thegateisbestremovedbyusingatrimfixture,especiallyonathicksectionpart.Sinceitisaratherlargescar,itisadvisabletolocatethegateatanon-cosmetic/non-functionalarea,ifpossible.,-50-,Gates:FlashGates,PartConfigurationThearrowsonthedrawingrepresenttheplasticflowfromthesprue,runner,flashgate,andintothepartcavity.Averythin,longflashgateisidealforthindials,andlargeflatsections,withanuninterruptedstraightedge.Thisstylegatehelpstodispersetheplasticmaterialintothecavityinawidepattern.,-51-,Gates:FlashGates,GateCosmeticsEnlargementAshowsaverythin,longscarleftfromtheflashgate.Thisgatehastheadvantageofleavingaverysmallcosmeticmarkonthepart,aswellasbeingeasilyremovedbyhand.Atrimfixturecouldbeusedifdesired.,-52-,Vents:,WhyVents:Asplasticmaterialisinjectedintoacavity,itmustdisplacetheairthatisalreadythere.Unlesstheairisremovedquicklyseveralthingscanhappen.Airwillbecometrappedandthencompressedincreasingitstemperatureenoughtocauseburnmarksorevenahole.Lackofproperventingcancauseanincreaseininjectionpressure,shortshots,splaymarks,poorweldlines,andahighdegreeofinternalstresses.VentsOverview:Allplasticmoldsareventedinonewayoranother.Airininjectionmoldscanescapearoundthepartingline,ejectorpins,slides,andinserts.Usuallythisisnotenoughbecauseofthevolumeofairthatmustbereleasedquickly.Thereforethemolddesignermustanticipatetrappedairlocationsanddesignadditionalventinglocations.,-53-,Vents:Moldingwithoutvent,Thispicturerepresentsplasticresinfillingacavitywithoutanyvents.Theairandanygasescausedfromheatingtheplasticresinaretrappedandcannotbedisplaced.Thiscompressesandraisesthetemperatureofthegases,causingtheplastictoburnorchar,whilepossiblycausingashortfillshot,-54-,Vents:Moldingwithvent,Thispicturerepresentsaplasticresinfillingacavitywithavent.Aventlandallowsthetrappedgasestoflowoutofthemoldcavity,butnottheplasticresinfillingthecavity.Thecavityshapeandsize,aswellasthetypeofplasticused,determinestheventlanddimensions.Theventreliefgrooveisdeeperpasttheventland,-55-,Vents:PartingLinevent,Thepartinglineventshownhererepresentsthemostcommontypeofventingused.Manymorecanbeusedwhererequired.Theventisusuallymadebygrindingashallow,narrowland,followedbyadeeperreliefgroove.Partsize,shape,andtypeofplasticdeterminetheventlandsize.Theventreliefgroovehelpstokeepthelandopen.,-56-,Vents:TroughPinVent,Thesedrawingsrepresentventingaroundanddownanejectorpin.Flatsaregroundtokeepthepincenteredandallowventing.Gasescanthenventthroughtheflats,intothereliefarea,andthenoutthemoldbase.Depthoftheflatsmustmatchtheresinviscositysothatonlythegasesmayescape.,-57-,ConsiderationofGatedesignandSelection,1、NumberofCavity2、Material/Resin3、Cosmeticandfunctionofparts4、Limitsofpartsshapeanddimension5、Limitsofinjectionmoldingmachine6、Easyforassemblyorsecondaryprocess7、Remainedstressofparts8、Productivity,-58-,WeldSlugWell,Gatedesign,-59-,ForFlatPart,Gatedesign,-60-,ToAvoidHesitation,Gatedesign,-61-,GateDesigntoAvoidSinkMark&Void,Gatedesign,-62-,AvoidJettingbyUsingOverlapGate,Gatedesign,-63-,AvoidJettingbyUsingTabGate,Gatedesign,-64-,AvoidJettingbyLocatingGateCorrectly,Gatedesign,-65-,AvoidJettingbyProfilingGateProperly,Gatedesign,-66-,SomeKeyPointsofMolddesign,Thelocationofthegateshouldbeinthemostthicknessarea,aswellasinthecenterofit.Strengthofcore:thesupportpinsmusttakeupthespaceexcepttheejectorarea.Ejection:Coulddoonephaseortwophases,butHookPincouldnotbetheonlyejector.Theejectorpin:howmuchistheejectorareaoftheproduct?Slider:payattentiontothestrengthofslider,andhasoilchannelforlubricationandwaterchannelforcoolingBoss:Thetoolofthebossareaneedstohaveejectionsleeve,notonlyforejectionbutalsoforventing.,-67-,MoldIntroductionLayOutForCavities,Oncethecavitynumberwasdecided,weshouldconsiderthefollowingitemsfortoollayoutAllcavitiestobefilledinthesametime.Theflowlength:theshorterthebetterThejoinforcesoftheallshouldgothroughthecenteroftheplate.EnoughSpaceforinjectorpins,locatingpins,cooling.etc.,-68-,MoldIntroductionCavityLayOut:(1)Circular,Advantage:Sameflowlengthtocavities.。Disadvantage:Limitedcavitylayout。,-69-,MoldIntroductionCavityLayOut:(2)lineup,Advantage:morecavitynumber.Disadvantage:differentflowlength,needtoadjustthesizeofeverylength.,-70-,MoldIntroduction:CavityLayOut:（2）Symmetry,Advantage:Morecavities,andthesameflowlength.Disadvantage:Longflowlength(difficulttofill,andmorematerialwastage),-71-,PurposesofMoldCoolingDesign,1.EvenCooling(ImprovePartQuality)2.EfficientCooling(IncreaseProductivity),-72-,CoolingDesignforThinPart,Thin-wallpartcannotaffordasmuchthermalinducedresidualstressastheconventionalonedoes.Anevencoolingdesignbecomesveryimportanttocontroltheshrinkageandwar-pageatanacceptablelevel.,-73-,IntroductiontoMold:InjectionMoldingCycleTime,FillTime,OpenTime,Post-fillTime,-74-,IntroductiontoMold:Min.PossibleCoolingTime,themin.possiblecoolingtime,themax.partthickness,thermaldiffusivityofthemelt,injectiontemp.,coolanttemp.,ejectiontemp.,-75-,MoldCoolingRecommendedDiameter,Depth&Pitch,D:DiameterofCoolingChannel,10to14mmd:Depth,D,to3DP:Pitch,3Dto5D,-76-,UnbalancedCoolingDesign,TaiwanGreenPointEnterprisesCo.,Ltd.,-77-,BalancedCoolingDesign,TaiwanGreenPointEnterprisesCo.,Ltd.,-78-,DifferentMoldTypes,(1).2-PlateMold(2).3-PlateMold,-79-,DifferentMoldTypes:2-PlateMold,-80-,DifferentMoldTypes:Typical2-PlateMold,-81-,DifferentMoldTypes:2-PlateMoldForThreadMechanism,-82-,DifferentMoldTypes:2-PlateMoldForSlide,-83-,DifferentMoldTypes:2-PlateMoldForSubmarineGates,-84-,DifferentMoldTypes:2-PlateMoldForSubmarineGates,-85-,DifferentMoldTypes:2-PlateMoldForVerticalInjectionMolding,-86-,DifferentMoldTypes:2-PlateMoldForInsertMolding,-87-,DifferentMoldTypes:2-PlateMoldForLif