SPCAttribute Control Charts.ppt

AttributeControlCharts 中国最大的资料库下载 LearningObjectives DefectivevsDefectBinomialandPoissonDistributionpChartnpChartcChartuChartTestsforInstability 中国最大的资料库下载 ShewhartControlCharts Overview 中国最大的资料库下载 DefectiveandDefect DefectiveAunitofproductthatdoesnotmeetcustomer srequirementorspecification Alsoknownasanon conformingunit ExampleAbasecastingthatfailsporosityspecificationisadefective Adiscclampthatdoesnotmeettheparallelismspecificationisadefective 中国最大的资料库下载 DefectAflaworasinglequalitycharacteristicthatdoesnotmeetcustomer srequirementorspecification Alsoknownasanon conformity Therecanbeoneormoredefectsinadefective ExampleAdentonaVCMpolethatfailscustomer sspecificationisadefect Astainonacoverthatfailscustomer 中国最大的资料库下载 DefectiveandDefect 中国最大的资料库下载 ShewhartControlChartsforAttributeData Thereare4typesofAttributeControlCharts 43 np c p u Defects PoissonDistribution Defectives BinomialDistribution 中国最大的资料库下载 TypesofDataandDistributions DiscreteData Attribute BinomialPoissonContinuousData Variable NormalExponentialWeibullLognormaltc2F DiscreteDistributions ContinuousDistributions 中国最大的资料库下载 TypesofDistributions NormalDistribution ExponentialDistribution UniformDistribution BinomialDistribution DiscreteDistributions ContinuousDistributions 中国最大的资料库下载 BinomialDistributionUsefulforattributedata orbinarydata Resultfrominspectioncriteriawhicharebinaryinnature e g pass fail go nogo accept reject etc Datageneratedfromcountingofdefectives DiscreteDistributions PlotisknownasProbabilityMassFunctionofX 中国最大的资料库下载 BinomialDistributionIfaprocesstypicallygives10 rejectrate p 0 10 whatisthechanceoffinding0 1 2or3defectiveswithinasampleof20units n 20 DiscreteDistributions CommonlyusedinAcceptanceSampling 中国最大的资料库下载 Thelocation dispersionandshapeofabinomialdistributionareaffectedbythesamplesize n anddefectiverate p BinomialDistribution DiscreteDistributions 中国最大的资料库下载 JamesBernoulli BinomialDistribution DiscreteDistributions 中国最大的资料库下载 PoissonDistributionUsefulfordiscretedatainvolvingerrorrate defectrate dpu dpmo particlecountrate etc Datageneratedfromcountingofdefects DiscreteDistributions 中国最大的资料库下载 PoissonDistributionIfaprocesstypicallygives4 0defectrate l 4dpu whatisthechanceoffinding0 1 2or3defectsperunit DiscreteDistributions Commonlyusedasanapproximationofthebinomialdistributionwhen p 0 1 10 nislarge 中国最大的资料库下载 Thelocation dispersionandshapeofaPoissondistributionareaffectedbythemean l PoissonDistribution DiscreteDistributions 中国最大的资料库下载 SimeonDPoisson PoissonDistribution DiscreteDistributions 中国最大的资料库下载 pChart FractionNon ConformingRejectRate DefectiveRatePercentFallout 2 0 1 0 0 0 5 0 4 0 3 0 2 0 1 0 0 S a m p l e N u m b e r P r o p o r t i o n 1 P 0 2 1 4 0 3 0 S L 0 3 8 8 0 3 0 S L 0 0 4 0 0 0 中国最大的资料库下载 pChart Fractionnon conforming p Ratioofnumberofdefectives ornon conformingitems inapopulationtothenumberofitemsinthatpopulation Samplefractionnon conforming p Ratioofnumberofdefectives d inasampletothesamplesize n i e Is p asamplestatistic 中国最大的资料库下载 Theunderlyingprinciplesofthepchartarebasedonthebinomialdistribution Thismeansthatifaprocesshasatypicalfractionnon conforming p themeanandvarianceofthedistributionforp sarecomputedfromthebinomialequation giving pChart k numberofsubgroup shouldbebetween20to25beforeconstructingcontrollimits Xi numberofdefectiveunitinsubgroupiwhichhasatotalsamplesizeofniunits 中国最大的资料库下载 Thepchartalsoassumesasymmetricalbell shapedistribution withsymmetricalcontrollimitsoneachsideofthecenterline Thisimpliesthatthebinomialdistributionisapproximatelyclosetotheshapeofthenormaldistribution whichcanhappenundercertainconditionsofpandn p 1 2andn 10implyingnp 5Forothervaluesofp thegeneralguidelineistohavenp 10togetasatisfactoryapproximationofthenormaltothebinomial pChart 中国最大的资料库下载 pChart FollowingShewhart sprinciple theCenterLineandControlLimitsofapchartare 中国最大的资料库下载 Ifthesamplesizeisnotconstant thentheControlLimitsofapchartmaybecomputedbyeithermethod a VariableControlLimitswhereniistheactualsamplesizeofeachsamplingib ControlLimitsBasedonAverageSampleSizewherenistheaverage ortypical samplesizeofallthesamples pChart 中国最大的资料库下载 WhentoUseControlLimitsBasedonAverageSampleSizeinsteadofVariableControlLimitsSmallestsubgroupsize nmin isatleast30 ofthelargestsubgroupsize nmax Futuresamplesizeswillnotdiffergreatlyfromthosepreviouslyobserved WhenusingControlLimitsBasedonAverageSampleSize theexactcontrollimitsofapointshouldbedeterminedandexaminedrelativetothatvalueif ThereisanunusuallylargevariationinthesizeofaparticularsampleThereisapointwhichisnearthecontrollimits pChart 中国最大的资料库下载 Example1 pChart S NSampledRejects1501225015350845010550465077501685099501410501011505125061350171450121550221650817501018505195013205011 Frozenorangejuiceconcentrateispackedin6 ozcardboardcans Ametalbottompanelisattachedtothecardboardbody Thecansareinspectedforpossibleleak 20samplingsofdifferentsamplingsizewereobtained Verifyiftheprocessisincontrol ThedataarefoundinSPCCharts MTW 中国最大的资料库下载 MiniTab sStat ControlCharts P Example1 pChart 中国最大的资料库下载 Example1 pChart 中国最大的资料库下载 Example1 pChart 中国最大的资料库下载 Example1 pChart MinitaballowsdifferencesetofcontrolchartstobeplottedononechartMiniTab sStat ControlCharts P 中国最大的资料库下载 Example1 pChart 中国最大的资料库下载 npChart Ifthesamplesizeisconstant itispossibletobaseacontrolchartonthenumbernonconforming np ratherthanthefractionnonconforming p TheCenterLineandControlLimitsofannpchartare 中国最大的资料库下载 Example2 npChart S NSampledRejects1501225015350845010550465077501685099501410501011505125061350171450121550221650817501018505195013205011 Frozenorangejuiceconcentrateispackedin6 ozcardboardcans Ametalbottompanelisattachedtothecardboardbody Thecansareinspectedforpossibleleak 20samplingsof50cans samplingwereobtained Verifyiftheprocessisincontrol ThedataarefoundinSPCCharts MTW 中国最大的资料库下载 Example2 npChart MiniTab sStat ControlCharts NP 中国最大的资料库下载 Example2 npChart 中国最大的资料库下载 pChartvsnpChart Foreaseofrecording thenpchartispreferred Thepchartoffersthefollowingadvantages accommodationforvariablesamplesizeprovidesinformationaboutprocesscapability 中国最大的资料库下载 SampleSizeforpandnpCharts SampleSizeisdeterminedbasedonthe2criteria AssumptiontoapproximateBinomialDistributiontoaNormalDistributionToensurethattheLCLisgreaterthanzero Forp 0 5 Forp othervalues 中国最大的资料库下载 cChart DefectsperUnit DPU ErrorRate DefectRateDefectsperOpportunity 2 0 1 0 0 2 0 1 0 0 S a m p l e N u m b e r S a m p l e C o u n t C 9 6 5 0 3 0 S L 1 8 9 7 3 0 S L 0 3 3 0 7 中国最大的资料库下载 cChart Eachspecificpointatwhichaspecificationisnotsatisfiedresultsinadefectornonconformity ThecchartisacontrolchartforthetotalnumberofdefectsinaninspectionunitbasedonthenormaldistributionasanapproximationforthePoissondistribution whichcanhappenwhen cor 15 中国最大的资料库下载 cChart InspectionUnitTheareaofopportunityfortheoccurrenceofnonconformities e g aHSA amedia aPCBAThisisanentitychosenforconvenienceofrecord keeping Itmayconstitutemorethan1unitofproduct e g aHSA bothsurfacesofamedia 10piecesofPCBA 中国最大的资料库下载 cChart Ifthenumberofnonconformities defects perinspectionunitisdenotedbyc then TheCenterLineandControlLimitsofacchartare 中国最大的资料库下载 uChart Incaseswherethenumberofinspectionunitsisnotconstant theuchartmaybeusedinstead with Iftheaveragenumberofdefectsperinspectionunitisdenotedbyu then Whereciisthecountofthenumberofdefectsinnumberofinspectionunits ai 中国最大的资料库下载 uChart TheCenterLineandControlLimitsofauchartare 中国最大的资料库下载 Example3 canduCharts S NUnitsDefects1510251235845145510651675118579510105151159125513571451115512165617581851019572055 Apersonalcomputermanufacturerplanstoestablishacontrolchartfornonconformitiesatthefinalassemblyline Thenumberofnonconformitiesin20samplesof5PCsareshownhere Verifyiftheprocessisin control 中国最大的资料库下载 Example3 canduCharts MiniTab sStat ControlCharts C 中国最大的资料库下载 Example3 canduCharts MiniTab sStat ControlCharts U 中国最大的资料库下载 Example3 canduCharts 中国最大的资料库下载 u orc Chartvsp np Chart Theu orc chartoffersthefollowingadvantages Moreinformativeasthetypeofnonconformityisnoted FacilitatesParetoanalysis FacilitatesCause EffectAnalysis 中国最大的资料库下载 c ChartMeasuresthetotalnumberofdefectsinasubgroupThesubgroupsizecanbe1unitofproductifweexpecttohavearelativelylargenumberofdefects unitRequiresaconstantsubgroupsizeu ChartMeasuresthenumberofdefects unitofproduct dpu Thesubgroupsizecanbeconstantorvariablep ChartMeasurestheproportionofdefectiveunitsinasubgroupThesubgroupsizecanbeconstantorvariablenp ChartMeasuresthenumberofdefectiveitemsinasubgroupRequiresaconstantsubgroupsize SelectingtheAppropriateChart 中国最大的资料库下载 Exercise 1 Strengthof5testpiecessampledeveryhourNumberofdefectivesin100partsNumberofsolderdefectsinaprintedcircuitboardassemblyDiameterof40unitsofproductssa