外文翻译注塑模具的设计及其热分析英文版.pdf

JournalofMaterialsProcessingTechnology171(2006)259267AbstracttheinUnigraphics,usingdistribresultsat©K1.industries,AlmostusagebymoldingtoatTherearetionappropriatesystemThiswithitypacke0924-0136/$doi:10.1016/j.jmatprotec.2005.06.075DesignandthermalanalysisofplasticinjectionmouldS.H.Tang,Y.M.Kong,S.M.Sapuan,R.Samin,S.SulaimanDepartmentofMechanicalandManufacturingEngineering,UniversitiPutraMalaysia,43400Serdang,Selangor,MalaysiaReceived3September2004；accepted21June2005Thispaperpresentsthedesignofaplasticinjectionmouldforproducingwarpagetestingspecimenandperformingthermalanalysisformouldtoaccessontheeffectofthermalresidualstressinthemould.Thetechnique,theory,methodsaswellasconsiderationneededdesigningofplasticinjectionmouldarepresented.DesignofmouldwascarriedoutusingcommercialcomputeraideddesignsoftwareVersion13.0.ThemodelforthermalresidualstressanalysisduetounevencoolingofthespecimenwasdevelopedandsolvedacommercialfiniteelementanalysissoftwarecalledLUSASAnalyst,Version13.5.Thesoftwareprovidescontourplotoftemperatureutionforthemodelandalsotemperaturevariationthroughtheplasticinjectionmoldingcyclebyplottingtimeresponsecurves.Theshowthatshrinkageislikelytooccurintheregionnearthecoolingchannelsascomparedtootherregions.Thisunevencoolingeffectdifferentregionsofmouldcontributedtowarpage.2005ElsevierB.V.Allrightsreserved.eywords:PlasticInjectionmould；Design；ThermalanalysisIntroductionby“coolingstage”wherethemouldiscooleduntilthepartissufficientlyrigidtobeejected.Thelaststepisthe“ejectionPlasticindustryisoneoftheworldsfastestgrowingrankedasoneofthefewbillion-dollarindustries.everyproductthatisusedindailylifeinvolvestheofplasticandmostoftheseproductscanbeproducedplasticinjectionmoldingmethod1.Plasticinjectionprocessiswellknownasthemanufacturingprocesscreateproductswithvariousshapesandcomplexgeometrylowcost2.Theplasticinjectionmoldingprocessisacyclicprocess.arefoursignificantstagesintheprocess.Thesestagesfilling,packing,coolingandejection.Theplasticinjec-moldingprocessbeginswithfeedingtheresinandtheadditivesfromthehoppertotheheating/injectionoftheinjectionplasticinjectionmoldingmachine3.isthe“fillingstage”inwhichthemouldcavityisfilledhotpolymermeltatinjectiontemperature.Afterthecav-isfilled,inthe“packingstage”,additionalpolymermeltisedintothecavityatahigherpressuretocompensatethexpectedshrinkageasthepolymersolidifies.ThisisfollowedCorrespondingauthor.E-mailaddress:saihongeng.upm.edu.my(S.H.Tang).stage”after4mericnatedactualthecoreandfmouldgatingtostressesdemoldedconductimolteneseefrontmatter©2005ElsevierB.V.Allrightsreserved.inwhichthemouldisopenedandthepartisejected,whichthemouldisclosedagaintobeginthenextcycle.Thedesignandmanufactureofinjectionmoldedpoly-partswithdesiredpropertiesisacostlyprocessdomi-byempiricism,includingtherepeatedmodificationoftooling.Amongthetaskofmoulddesign,designingmouldspecificsupplementarygeometry,usuallyontheside,isquitecomplicatedbytheinclusionofprojectiondepression5.Inordertodesignamould,manyimportantdesigningactorsmustbetakenintoconsideration.Thesefactorsaresize,numberofcavity,cavitylayouts,runnersystems,systems,shrinkageandejectionsystem6.Inthermalanalysisofthemould,themainobjectiveisanalyzetheeffectofthermalresidualstressormolded-inonproductdimension.Thermallyinducedstressesvelopprincipallyduringthecoolingstageofaninjectionpart,mainlyasaconsequenceofitslowthermalvityandthedifferenceintemperaturebetweentheresinandthemould.Anuneventemperaturefieldxistsaroundproductcavityduringcooling7.260Processingenceschannel.eSignificantfore,ofunderstandingtion,beproducingmalresidual2.2.1.specimenthatthinuctthemouldedshell120materialwtemperature,respectiduced.2.2.testingerationstestinginjectioncarbontheiii.iimen,designsionismachineTheTherefore,notreservsetting-upS.H.Tangetal./JournalofMaterialsDuringcooling,locationnearthecoolingchannelexperi-morecoolingthanlocationfarawayfromthecoolingThisdifferenttemperaturecausesthematerialtoxperiencedifferentialshrinkagecausingthermalstresses.thermalstresscancausewarpageproblem.There-itisimportanttosimulatethethermalresidualstressfieldtheinjection-moldedpartduringthecoolingstage8.Bythecharacteristicsofthermalstressdistribu-deformationcausedbythethermalresidualstresscanpredicted.Inthispaperthedesignofaplasticinjectionmouldforwarpagetestingspecimenandforperformingther-analysisforthemouldtoaccessontheeffectofthermalstressinthemouldispresented.MethodologyDesignofwarpagetestingspecimenThissectionillustratesthedesignofthewarpagetestingtobeusedinplasticinjectionmould.Itisclearwarpageisthemainproblemthatexistsinproductwithshellfeature.Therefore,themainpurposeoftheprod-developmentistodesignaplasticpartfordeterminingeffectivefactorsinthewarpageproblemofaninjection-partwithathinshell.Thewarpagetestingspecimenisdevelopedfromthinplastics.Theoveralldimensionsofthespecimenweremminlength,50mminwidthand1mminthickness.Theusedforproducingthewarpagetestingspecimenasacrylonitrilebutadienestylene(ABS)andtheinjectiontimeandpressurewere210C,3sand60MPa,vely.Fig.1showsthewarpagetestingspecimenpro-DesignofplasticinjectionmouldforwarpagespecimenThissectiondescribesthedesignaspectsandotherconsid-involvedindesigningthemouldtoproducewarpagespecimen.ThematerialusedforproducingtheplasticFig.1.Warpagetestingspecimenproduced.imumbasefittedlosionsha(reactiontherespectionspacewithTherefore,TMouldComponentsTCaCoreSideEjectorEjectorBottomTechnology171(2006)259267mouldforwarpagetestingspecimenwasAISI1050steel.Fourdesignconceptshadbeenconsideredindesigningofmouldincluding:i.Three-platemould(Concept1)havingtwopartinglinewithsinglecavity.Notapplicableduetohighcost.ii.Two-platemould(Concept2)havingonepartinglinewithsinglecavitywithoutgatingsystem.Notapplicableduetolowproductionquantityperinjection.Two-platemould(Concept3)havingonepartinglinewithdoublecavitieswithgatingandejectionsystem.Notapplicableasejectorpinsmightdamagetheproductastheproductistoothin.v.Two-platemould(Concept4)havingonepartinglinewithdoublecavitieswithgatingsystem,onlyusedspruepulleractasejectortoavoidproductdamageduringejection.Indesigningofthemouldforthewarpagetestingspec-thefourthdesignconcepthadbeenapplied.Variousconsiderationshadbeenappliedinthedesign.Firstly,themouldwasdesignedbasedontheplatendimen-oftheplasticinjectionmachineused(BOY22D).Therealimitationofthemachine,whichisthemaximumareaofplatenisgivenbythedistancebetweentwotiebars.distancebetweentiebarsofthemachineis254mm.themaximumwidthofthemouldplateshouldexceedthisdistance.Furthermore,4mmspacehadbeenedbetweenthetwotiebarsandthemouldformouldandhandlingpurposes.Thisgivesthefinalmax-widthofthemouldas250mm.Thestandardmouldwith250mm×250mmisemployed.ThemouldbaseistothemachineusingMatexclampattheupperrightandwerleftcornerofthemouldbaseormouldplaten.Dimen-ofotherrelatedmouldplatesareshowninTable1.Themouldhadbeendesignedwithclampingpressurevingclampingforcehigherthantheinternalcavityforceforce)toavoidflashingfromhappening.Basedonthedimensionsprovidedbystandardmouldset,widthandtheheightofthecoreplateare200and250mm,vely.Thesedimensionsenableddesignoftwocavitiescoreplatetobeplacedhorizontallyasthereisenoughwhilethecavityplateisleftemptyanditisonlyfixedspruebushingforthepurposeoffeedingmoltenplastics.itisonlyonestandardpartinglinewasdesignedatable1platesdimensions.Size(mm)width×height×thicknessopclampingplate250×250×25vityplate200×250×40plate200×250×40plate/supportplate37×250×70-retainerplate120×250×15plate120×250×20clampingplate250×250×25Processingthereleasedopening.islandonlywforrunneringcase.moretype.Thisthediameterorsametheairandflashinginorthatoccurring.caecacientshocoretheFig.2.Cavitylayoutwithairventsandcoolingchannels.plate.Thespruepullerlocatedatthecenterofcoreplatenotonlyfunctionsasthepullertoholdtheproductinpositionwhenthemouldisopenedbutitalsoactsasejectortopushtheproductoutofthemouldduringejectionstage.Noaddi-tionalejectorisusedorlocatedatproductcavitiesbecausetheproductproducedisverythin,i.e.1mm.Additionalejec-torintheproductcavityareamightcreateholeanddamagetotheproductduringejection.Finally,enoughtoleranceofdimensionsisgivenconsid-erationtocompensateforshrinkageofmaterials.Fig.3shows3DsolidmodelingaswellasthewireframemodelingofthemoulddevelopedusingUnigraphics.S.H.Tangetal./JournalofMaterialssurfaceoftheproduct.TheproductandtherunnerwereinaplanethroughthepartinglineduringmouldStandardorsidegatewasdesignedforthismould.Thegatelocatedbetweentherunnerandtheproduct.Thebottomofthegatewasdesignedtohave20slantingandhas0.5mmthicknessforeasyde-gatingpurpose.Thegateasalsodesignedtohave4mmwidthand0.5mmthicknesstheentranceofmoltenplastic.Inthemoulddesign,theparaboliccrosssectiontypeofwasselectedasithastheadvantageofsimplermachin-inonemouldhalfonly,whichisthecoreplateinthisHowever,thistypeofrunnerhasdisadvantagessuchasheatlossandscrapcomparedwithcircularcrosssectionThismightcausethemoltenplastictosolidifyfaster.problemwasreducedbydesigninginsuchawaythatrunnerisshortandhaslargerdiameter,whichis6mmin.Itisimportantthattherunnerdesigneddistributesmaterialmoltenplasticintocavitiesatthesametimeunderthepressureandwiththesametemperature.Duetothis,cavitylayouthadbeendesignedinsymmetricalform.Anotherdesignaspectthatistakenintoconsiderationwasventdesign.Thematingsurfacebetweenthecoreplatethecavityplatehasveryfinefinishinginordertopreventfromtakingplace.However,thiscancauseairtotrapthecavitywhenthemouldisclosedandcauseshortshotincompletepart.SufficientairventwasdesignedtoensureairtrapcanbereleasedtoavoidincompletepartfromThecoolingsystemwasdrilledalongthelengthofthevitiesandwaslocatedhorizontallytothemouldtoallowvencooling.Thesecoolingchannelsweredrilledonbothvityandcoreplates.Thecoolingchannelsprovidedsuffi-coolingofthemouldinthecaseofturbulentflow.Fig.2wscavitylayoutwithairventsandcoolingchannelsonplate.Inthismoulddesign,theejectionsystemonlyconsistsofejectorretainerplate,spruepullerandalsotheejector3.3.1.testingrun.shortairFig.3.3DsolidmodelingandwireframeTechnology171(2006)259267261ResultsanddiscussionResultsofproductproductionandmodificationFromthemoulddesignedandfabricated,thewarpagespecimensproducedhavesomedefectsduringtrialThedefectsareshortshot,flashingandwarpage.Theshotissubsequentlyeliminatedbymillingofadditionalventsatcornersofthecavitiestoallowairtrappedtomodelingofthemould.262Processingescape.packingbyinjectionitylittletheeliminate3.2.oftionthedirectedthe35mensureselectedingfiniteandcoreformed.Fig.5.Modelforthermalanalysis.TMaterialCarbonDensityYPoissonYTThermalConductiSpecificS.H.Tangetal./JournalofMaterialsFig.4.Extraairventstoavoidshortshot.Meanwhile,flashingwasreducedbyreducingthepressureofthemachine.Warpagecanbecontrolledcontrollingvariousparameterssuchastheinjectiontime,temperatureandmeltingtemperature.Afterthesemodifications,themouldproducedhighqual-warpagetestingspecimenwithlowcostandrequiredfinishingbyde-gating.Fig.4showsmodificationsofmould,whichismachiningofextraairventsthatcanshortshot.DetailanalysisofmouldandproductAfterthemouldandproductsweredeveloped,theanalysismouldandtheproductwascarriedout.Intheplasticinjec-mouldingprocess,moltenABSat210Cisinjectedintomouldthroughthespruebushingonthecavityplateandintotheproductcavity.Aftercoolingtakesplace,productisformed.Onecycleoftheproducttakesaboutsincluding20sofcoolingtime.Thematerialusedforproducingwarpagetestingspeci-wasABSandtheinjectiontemperature,timeandpres-were210C,3sand60MParespectively.ThematerialforthemouldwasAISI1050carbonsteel.Propertiesofthesematerialswereimportantindetermin-temperaturedistributioninthemouldcarriedoutusingelementanalysis.Table2showsthepropertiesforABSAISI1050carbonsteel.ThecriticalpartofanalysisformouldisonthecavityandplatebecausethesearetheplacewheretheproductisTherefore,thermalanalysistostudythetemperaturedistribperformedcalled(2D)ofmodelingsidetogetheranalysisandelementresponsedurationanalysisBasicallythethethe3.3.analysistimeable2propertiesformouldandproductSteel(AISI1050),mould,7860kg/m3oungsmodulus,E208GPasratio,0.297ieldstrength,SY365.4MPaensilestrength,SUTS636MPaexpansion,11.65×106K1vity,k49.4W/(mK)heat,c477J/(kgK)Technology171(2006)259267utionandtemperatureatthroughdifferenttimesareusingcommercialfiniteelementanalysissoftwareLUSASAnalyst,Version13.5.Atwo-dimensionalthermalanalysisiscarriedoutfortostudytheeffectthermalresidualstressonthemouldatdifferentregions.Duetosymmetry,thethermalanalysiswasperformedbyonlythetophalfoftheverticalcrosssectionorviewofboththecavityandcoreplatethatwereclampedduringinjection.Fig.5showsthemodelofthermalanalyzedwithirregularmeshing.Modelingforthemodelalsoinvolvesassigningpropertiesprocessorcycletimetothemodel.Thisallowedthefinitesolvertoanalyzethemouldmodeledandplottimegraphstoshowtemperaturevariationoveracertainandatdifferentregions.Fortheproductanalysis,atwodimensionaltensilestresswascarriedusingLUSASAnalyst,Version13.5.theproductwasloadedintensionononeendwhileotherendisclamped.Loadincrementswereapplieduntilmodelreachesplasticity.Fig.6showsloadedmodelofanalysis.ResultanddiscussionformouldandproductFormouldanalysis,thethermaldistributionatdifferentintervalswasobserved.Fig.7showsthe2DanalysisABSPolymer,productDensity,1050kg/m3Youngsmodulus,E2.519GPaPoissonsratio,0.4Yieldstrength,SY65MPaThermalexpansion,65×106K1Conductivity,k0.135W/(mK)Specificheat,c1250J/(kgK)