The Mould Design Guide

TheMouldDesignGuidePeterJonesTheMouldDesignGuidePeterJonesSmithersRapraTechnologyLimitedAwhollyownedsubsidiaryofTheSmithersGroupShawbury,Shrewsbury,Shropshire,SY44NR,UnitedKingdomTelephone:[phone]Fax:[phone]©2008,SmithersRapraTechnologyLimitedAllrightsreserved.Exceptaspermittedundercurrentlegislationnopartofthispublicationmaybephotocopied,reproducedordistributedinanyformorbyanymeansorstoredinadatabaseorretrievalsystem,withoutthepriorpermissionfromthecopyrightholder.AcataloguerecordforthisbookisavailablefromtheBritishLibrary.Everyefforthasbeenmadetocontactcopyrightholdersofanymaterialreproducedwithinthetextandtheauthorsandpublishersapologiseifanyhavebeenoverlooked.Typesetbydocumen.co.ukCoverdesignedbySmithersRapraTechnologyLimitedPrintedandboundbyLightningSourceSoft-backedISBN:978-1-84735-088-6Hard-backedISBN:978-1-84735-087-9iContents1Introduction.........................................................................................................12TheInjectionMouldingProcess............................................................................52.1Background..............................................................................................52.2MachineDesign........................................................................................62.2.1MachineBaseUnit......................................................................62.2.2ClampUnit.................................................................................62.2.3MouldHeight.............................................................................62.2.4Daylight......................................................................................72.2.5DistanceBetweenTieBars...........................................................82.2.6ClampingMechanisms................................................................92.2.7TheInjectionUnit.....................................................................132.3TheoreticalMouldLockingForce............................................................192.4TheMouldingCycle...............................................................................202.4.1MouldClosingPhase.................................................................202.4.2MouldProtectionPhase............................................................202.4.3Injection(MouldFilling)Phase..................................................202.4.4HoldingTimeandPressurisingPhase.........................................202.4.5CoolingandRefillPhase............................................................212.4.6ScrewBackPhase......................................................................212.4.7MouldOpenPhase....................................................................212.4.8EjectionPhase...........................................................................22MouldDesignGuideii3PlasticsMaterials................................................................................................233.1TypesofPlasticsMaterials......................................................................233.2DefinitionofPlastics...............................................................................233.3TheNatureofPlasticsMaterials.............................................................243.4Monomers,PolymerisationandPolymers................................................253.5ClassificationofPlastics..........................................................................263.5.1ThermosetsandThermoplastics................................................263.5.2Homopolymers,CopolymersandPolymerBlends(Alloys).........273.5.3AmorphousandSemicrystallineThermoplastics........................293.6MeltingandSolidification.......................................................................303.7Shrinkage...............................................................................................313.8EngineeringandCommodityPlastics.......................................................323.8.1EngineeringPlastics...................................................................323.8.2CommodityPlastics..................................................................323.9MaterialAdditives..................................................................................333.10FlowPropertiesofThermoplasticMaterials.............................................353.11VariableMolecularWeight.....................................................................353.12MeltFlowIndex(MFI)...........................................................................363.13ReprocessedMaterial..............................................................................373.14PolymerMolecules..................................................................................373.15MaterialNamesandAbbreviations.........................................................373.16MaterialApplications.........