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【英文标准名称】:StandardPracticeforUseofProcessOrientedAOQLandLTPDSamplingPlans
【原文标准名称】:使用过程导向的平均质量检查最低限和批量允许不良率的抽样方案的标准实施规程
【标准号】:ASTME1994-2009
【标准状态】:现行
【国别】:美国
【发布日期】:2009
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:E11.30
【标准类型】:(Practice)
【标准水平】:()
【中文主题词】:
【英文主题词】:averageoutgoingqualitylimit;lottolerancepercentdefective;sampling;samplingplans;AOQL(averageoutgoingqualitylimit)--samplingplans;Doublesamplingtable;LTPD(lottolerancepercentdefective);Sampling;Samplingdataanalysis/statistics;S
【摘要】:Twogeneraltypesoftables(Note1)aregiven,onebasedontheconceptoflottolerance,LTPD,andtheotheronAOQL.Thebroadconditionsunderwhichthedifferenttypeshavebeenfoundbestadaptedareindicatedbelow.Foreachofthetypes,tablesareprovidedbothforsinglesamplingandfordoublesampling.Eachoftheindividualtablesconstitutesacollectionofsolutionstotheproblemofminimizingtheover-allamountofinspection.Becauseeachlineinthetablescoversarangeoflotsizes,theAOQLvaluesintheLTPDtablesandtheLTPDvaluesintheAOQLtablesareoftenconservative.Note18212;TablesinAnnexA1-AnnexA4andpartsofthetextarereproducedbypermissionofJohnR.WileyandSons.Moreextensivetablesanddiscussionofthemethodswillbefoundinthattext.Thesamplingtablesbasedonlotqualityprotection(LTPD)(thetablesinAnnexA1andAnnexA2)areperhapsbestadaptedtoconditionswhereinterestcentersoneachlotseparately,forexample,wheretheindividuallottendstoretainitsidentityeitherfromashipmentoraservicestandpoint.Thesetableshavebeenfoundparticularlyusefulininspectionsmadebytheultimateconsumerorapurchasingagentforlotsorshipmentspurchasedmoreorlessintermittently.Thesamplingtablesbasedonaveragequalityprotection(AOQL)(thetablesinAnnexA3andAnnexA4)areespeciallyadaptedforusewhereinterestcentersontheaveragequalityofproductafterinspectionratherthanonthequalityofeachindividuallotandwhereinspectionis,therefore,intendedtoserve,ifnecessary,asapartialscreenfordefectivepieces.Thelatterpointofviewhasbeenfoundparticularlyhelpful,forexample,inconsumerinspectionsofcontinuingpurchasesoflargequantitiesofaproductandinmanufacturingprocessinspectionsofpartswheretheinspectionlotstendtolosetheiridentitybymergerinacommonstoreroomfromwhichquantitiesarewithdrawnonorderasneeded.Theplansbasedonaveragequalityprotection(AOQL)considerthedegreetowhichtheentireinspectionprocedurescreensoutdefectivesintheproductsubmittedtotheinspector.Lotsacceptedbysampleundergoapartialscreeningthroughtheeliminationofdefectivesfoundinsamples.Lotsthatfailtobeacceptedbysamplearecompletelyclearedofdefectives.Obviously,thisrequiresanondestructivetest.Theover-allresultissomeaveragepercentdefectiveintheproductasitleavestheinspector,termedtheaverageoutgoingquality,whichdependsonthelevelofpercentdefectiveforincomingproductandtheproportionoftotaldefectivesthatarescreenedout.Givenaspecificproblemofreplacinga100%screeninginspectionbyasamplinginspection,thefirststepistodecideonthetypeofprotectiondesired,toselectthedesiredlimitofpercentdefectivelottolerance(LTPD)orAOQLvalueforthattypeofprotection,andtochoosebetweensingleanddoublesampling.Thisresultsintheselectionofoneoftheappendedtables.Thesecondstepistodeterminewhetherthequalityofproductisgoodenoughtowarranttheintroductionofsampling.Theeconomiesofsamplingwillberealized,ofcourse,onlyinsofarasthepercentdefectiveinsubmittedproductissuchthattheacceptancecriteriaoftheselectedsamplingplanwillbemet.Astatisticalanalysisofpastinspectionresultsshouldfirstbemade,therefore,inordertodetermineexistinglevelsandfluctuationsinthepercentdefectiveforthecharacteristicorthegroupofcharacteristicsunderconsideration.Thisprovidesinformationwithrespecttothedegreeofcontrolaswellastheusuallevelofpercentdefectivetobeexpectedunderexistingconditions.Determineavaluefromthisandotherinformationfortheprocessaverage