processcapability(CP,CPK,PPK)

1©NOKIA2001T0001801.PPT/21-Dec-2001/JimChristyCompanyConfidentialProcessCapability(Cp/Cpk/Pp/Ppk)GlobalTrainingMaterialCreator:GlobalMechanicsProcessManagerFunction:MechanicsApprover:GaryBradley/GlobalProcessTeamDocumentID:DMT00018-ENVersion/Status:V.1.0/ApprovedLocation:Notes:\\…\NMP\DOCMANR4\PCP\PCProcessLibraryDocManChangeHistory:IssueDateHandledByComments1.021stDec’01JimChristy&SørenLundsfrydApprovedforGlobalUseNOTE–Allcommentsandimprovementsshouldbeaddressedtothecreatorofthisdocument.2©NOKIA2001T0001801.PPT/21-Dec-2001/JimChristyCompanyConfidentialContentsSectionHeading/DescriptionPage1Variation,TolerancesandDimensionalControl42Population,SampleandNormalDistribution153CpandCpkConcept284UseoftheNMPDataCollectionSpreadsheet445ConfidenceofCpk523©NOKIA2001T0001801.PPT/21-Dec-2001/JimChristyCompanyConfidentialProcessCapability-EvaluatingManufacturingVariationAcknowledgements•BennyMatthiassen(NMPCMT,Copenhagen,Denmark)•FrankAdler(NMPAlliance,Dallas,USA)•JoniLaakso(NMPR&D,Salo,Finland)•JimChristy(NMPSRC,Southwood,UK)4©NOKIA2001T0001801.PPT/21-Dec-2001/JimChristyCompanyConfidentialSection1Variation,TolerancesandDimensionalControl5©NOKIA2001T0001801.PPT/21-Dec-2001/JimChristyCompanyConfidentialTwoTypesofProductCharacteristicsVariable:Acharacteristicmeasuredinphysicalunits,e.g.millimetres,volts,amps,decibelandseconds.ONOFFAttribute:Acharacteristicthatbycomparisontosomestandardisjudged“good”or“bad”,e.g.freefromscratches(visualquality).6©NOKIA2001T0001801.PPT/21-Dec-2001/JimChristyCompanyConfidentialTheSourcesofProcess/SystemVariationMethodsOperatorsCustomerSatisfactionMaterialEnvironmentEquipmentProcess7©NOKIA2001T0001801.PPT/21-Dec-2001/JimChristyCompanyConfidentialTwoTypesofProcesses•Allprocesseshave:–Natural(random)variability=duetocommoncauses•StableProcess:Aprocessinwhichvariationinoutcomesarisesonlyfromcommoncauses•UnstableProcess:AprocessinwhichvariationisaresultofbothcommonandspecialcausesUSLLSLnominalvalueDefectUSLLSLnominalvalue–Unnaturalvariability=duetospecialcauses8©NOKIA2001T0001801.PPT/21-Dec-2001/JimChristyCompanyConfidentialShewhart(1931)TheTwoCausesofVariation•CommonCauses:–Causesthatareimplementedintheprocessduetothedesignoftheprocess,andaffectalloutcomesoftheprocess–IdentifyingthesetypesofcausesrequiresmethodssuchasDesignofExperiment(DOE),etc.•SpecialCauses:–Causesthatarenotpresentintheprocessallthetimeanddonotaffectalloutcomes,butarisebecauseofspecificcircumstances–SpecialcausescanbeidentifiedusingStatisticalProcessControl(SPC)USLLSLNominalvalueDefectUSLLSLnominalvalue9©NOKIA2001T0001801.PPT/21-Dec-2001/JimChristyCompanyConfidentialTolerancesLSL(lowerspecificationlimit)10,7USL(upperspecificationlimit)10,9AcceptablepartRejectedPartRejectedProductNominal10,80,1RejectedPartAtoleranceisaallowedmaximumvariationofadimension.10©NOKIA2001T0001801.PPT/21-Dec-2001/JimChristyCompanyConfidentialMeasurementReportInmostcaseswemeasureonlyonepartpercavityformeasurementreport11©NOKIA2001T0001801.PPT/21-Dec-2001/JimChristyCompanyConfidentialExampleofCapabilityAnalysisData•Forsomecriticaldimensionsweneedtomeasuremorethan1part•Forcapabilitydataweusuallymeasure5pcs2times/hour=100pcs(butsamplingplanneedstobemadeonthebasisofproductionquantity,rundurationandcycletime)1stSubgroup2ndSubgroup3rdSubgroup4thSubgroup118.53118.52118.54118.56118.54118.54118.52118.55118.51118.51118.50118.55118.53118.51118.52118.55118.51118.54118.54118.555thSubgroup6thSubgroup7thSubgroup8thSubgroup118.55118.54118.57118.60118.54118.56118.56118.57118.55118.55118.57118.55118.54118.54118.55118.56118.56118.53118.54118.559thSubgroup10thSubgroup11thSubgroup12thSubgroup118.60118.61118.58118.60118.59118.60118.60118.63118.58118.61118.61118.63118.60118.59118.60118.61118.59118.59118.59118.6412©NOKIA2001T0001801.PPT/21-Dec-2001/JimChristyCompanyConfidentialProcessCapability-Whatisit?•ProcessCapabilityisameasureoftheinherentcapabilityofamanufacturingprocesstobeabletoconsistentlyproducecomponentsthatmeettherequireddesignspecifications•ProcessCapabilityisdesignatedbyCpandCpk•ProcessPerformanceisameasureoftheperformanceofaprocesstobeabletoconsistentlyproducecomponentsthatmeettherequireddesignspecifications.ProcessPerformanceincludesspecialcausesofvariationnotpresentinProcessCapability•ProcessPerformanceisdesignatedPpandPpk13©NOKIA2001T0001801.PPT/21-Dec-2001/JimChristyCompanyConfidentialWhyMakeProcessCapabilityStudiesLSL(lowerspecificationlimit)10,7USL(upperspecificationlimit)10,9Nominal10,80,1Thispartiswithinspec.ThetoolwouldbeapprovedifonlythispartwasmeasuredThesepartsareoutofspecandcouldbeapprovedifonlyonegoodpartwasmeasuredAprocesscapabilitystudywouldrevealthatthetoolshouldnotbeacceptedWhenadimensionneedstobekeptproperlywithinspec,wemuststudytheprocesscapability….butstillthisisnoguaranteefortheactualperformanceoftheprocessasitisonlyaninitialcapabilitystudy14©NOKIA2001T0001801.PPT/21-Dec-2001/JimChristyCompanyConfidentialE1.5E1E2E3E4E5TheNokiaProcessVerificationProcessBlackdiamondstobefixedbyE3(oftenachangeofawhitediamond)Proposalforblackdiamondstobedi