【英文标准名称】:StandardTestMethodofMeasuringShrinkagefromMoldDimensionsofThermoplastics
【原文标准名称】:热塑塑料的模型尺寸收缩率测量的标准试验方法
【标准号】:ASTMD955-2000
【标准状态】:现行
【国别】:
【发布日期】:2000
【实施或试行日期】:
【发布单位】:美国材料与试验协会(ASTM)
【起草单位】:D20.09
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:试验;收缩;塑料
【英文主题词】:moldshrinkage;shrinkage;thermoplastics;
【摘要】:InjectionMolding8212;Ininjectionmolding,thedifferencebetweenthedimensionsofamoldcavityandofthemoldedspecimenmayvaryaccordingtothedesignofthemoldandoperationofthemoldingprocess.Factorssuchasmoldandmelttemperature,filltimes,andpackingconditionsareknowntoaffectshrinkagesignificantly.Adherencetothespecifiedmolddesign(see7.1)andspecificationsoutlinedinPracticeD3641orISO294-4ortheappropriatematerialwillimprovethereproducibilityofthetest.CompressionMolding8212;Incompressionmolding,thedifferencebetweenthedimensionsofamoldcavityandofthemoldedspecimenmayvaryaccordingtothedesignofthemoldandoperationofthemoldingprocess.Factors,suchastheamountofmaterialincharge,coolingtime,andpressureapplicationareknowntoaffectshrinkagesignificantly.Adherencetothespecifiedmolddesign(see7.2)andspecificationsoutlinedinPracticeD4703orISO293ortheappropriatematerialspecificationswillimprovethereproducibilityofthetest.1.1Thistestmethodisintendedtomeasureshrinkagefrommoldcavitytomoldeddimensionsofthermoplasticswhenmoldedbycompressionorinjectionprocesseswithspecifiedprocessconditions.1.2Thistestmethodcoversinitialshrinkagemeasurements.Themethodalsoaccommodatesshrinkageat24and48h,whichmaybecriticalforsomematerials.1.3Thismethodwillgivecomparabledatabasedonstandardspecimensandcannotpredictabsolutevaluesinactualmoldedpartswithvaryingflowpaths,wallthicknesses,pressuregradientsandprocessconditions.Differencesinmoldshrinkagemayalsobeobservedbetweenthethreespecimengeometriesdescribedinthistestmethod.1.4ThevaluesstatedinSIunitsaretoberegardedasthestandard.Thevaluesgiveninparenthesesaregivenforinformationonly.1.5Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeterminetheapplicabilityofregulatorylimitationspriortouse.Note1--ThistestmethodistechnicallyidenticaltoISO294-4whereTypeD2specimensareusedexceptthatpressuretransducersareanoptioninthistestmethodandrequiredinISO294-4.
【中国标准分类号】:G33
【国际标准分类号】:83_140_10
【页数】:5P.;A4
【正文语种】: