Designation:D955−08(Reapproved2014)StandardTestMethodofMeasuringShrinkagefromMoldDimensionsofThermoplastics1ThisstandardisissuedunderthefixeddesignationD955;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope1.1Thistestmethodisintendedtomeasureshrinkagefrommoldcavitytomoldeddimensionsofthermoplasticswhenmoldedbycompressionorinjectionprocesseswithspecifiedprocessconditions.1.2Thistestmethodcoversshrinkagemeasurementsat24and48hours.1.3Thismethodwillgivecomparabledatabasedonstan-dardspecimensandcannotpredictabsolutevaluesinactualmoldedpartswithvaryingflowpaths,wallthicknesses,pres-sureandtemperaturegradientsandprocessconditions.Differ-encesinmoldshrinkagemayalsobeobservedamongthethreespecimengeometriesdescribedinthistestmethod.1.4ThevaluesstatedinSIunitsaretoberegardedasthestandard.Thevaluesgiveninparenthesesaregivenforinformationonly.1.5Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.NOTE1—ThisstandardandISO294-3areequivalentinthedesignofspecimenD2.ThistestmethodisequivalenttoISO294-4whereTypeD2specimensandtheprocedureinAppendixX2areused.2.ReferencedDocuments2.1ASTMStandards:2D618PracticeforConditioningPlasticsforTestingD788ClassificationSystemforPoly(MethylMethacrylate)(PMMA)MoldingandExtrusionCompoundsD883TerminologyRelatingtoPlasticsD3641PracticeforInjectionMoldingTestSpecimensofThermoplasticMoldingandExtrusionMaterialsD4066ClassificationSystemforNylonInjectionandExtru-sionMaterials(PA)D4549ClassificationSystemandBasisforSpecificationforPolystyreneandRubber-ModifiedPolystyreneMoldingandExtrusi...
