Nokia生產(chǎn)過程控制全球培訓(xùn)教材

Nokia生產(chǎn)過程控制全球培訓(xùn)教材2024/3/12Nokia生產(chǎn)過程控制全球培訓(xùn)教材ContentsSection Heading/Description Page1 Variation,TolerancesandDimensionalControl 4 2 Population,SampleandNormalDistribution 153 CpandCpkConcept 284 UseoftheNMPDataCollectionSpreadsheet 445 ConfidenceofCpk 52 Nokia生產(chǎn)過程控制全球培訓(xùn)教材ProcessCapability-EvaluatingManufacturingVariationAcknowledgementsBennyMatthiassen (NMPCMT,Copenhagen,Denmark)FrankAdler (NMPAlliance,Dallas,USA)JoniLaakso (NMPR&D,Salo,Finland)JimChristy (NMPSRC,Southwood,UK)Nokia生產(chǎn)過程控制全球培訓(xùn)教材Section1Variation,TolerancesandDimensionalControlNokia生產(chǎn)過程控制全球培訓(xùn)教材TwoTypesofProductCharacteristicsVariable:Acharacteristicmeasuredinphysicalunits,e.g.millimetres,volts,amps,decibelandseconds.ONOFFAttribute:Acharacteristicthatbycomparisontosomestandardisjudged“good”or“bad”,e.g.freefromscratches(visualquality).InthistrainingwedealwithvariablesonlyNokia生產(chǎn)過程控制全球培訓(xùn)教材TheSourcesofProcess/SystemVariationMethodsOperatorsCustomerSatisfactionMaterialEnvironmentEquipmentProcessNokia生產(chǎn)過程控制全球培訓(xùn)教材TwoTypesofProcessesAllprocesseshave:Natural(random)variability

=>duetocommoncausesStableProcess:

AprocessinwhichvariationinoutcomesarisesonlyfromcommoncausesUnstableProcess:

AprocessinwhichvariationisaresultofbothcommonandspecialcausesUSLLSLnominalvalueDefectUSLLSLnominalvalue

Unnaturalvariability=>duetospecialcausesNokia生產(chǎn)過程控制全球培訓(xùn)教材Shewhart(1931)TheTwoCausesofVariationCommonCauses:Causesthatareimplementedintheprocessduetothedesignoftheprocess,andaffectalloutcomesoftheprocessIdentifyingthesetypesofcausesrequiresmethodssuchasDesignofExperiment(DOE),etc.

SpecialCauses:Causesthatarenotpresentintheprocessallthetimeanddonotaffectalloutcomes,butarisebecauseofspecificcircumstancesSpecialcausescanbeidentifiedusingStatisticalProcessControl(SPC)USLLSLNominal

valueDefectUSLLSLnominal

valueNokia生產(chǎn)過程控制全球培訓(xùn)教材TolerancesLSL(lowerspecificationlimit)10,7USL(upperspecificationlimit)10,9AcceptablepartRejectedPartRejectedProductNominal10,80,1RejectedPartAtoleranceisaallowedmaximumvariationofadimension.Nokia生產(chǎn)過程控制全球培訓(xùn)教材MeasurementReportInmostcaseswemeasureonlyonepartpercavityformeasurementreportNokia生產(chǎn)過程控制全球培訓(xùn)教材ExampleofCapabilityAnalysisDataForsomecriticaldimensionsweneedtomeasuremorethan1partForcapabilitydataweusuallymeasure5pcs2times/hour=100pcs(butsamplingplanneedstobemadeonthebasisofproductionquantity,rundurationandcycletime)Nokia生產(chǎn)過程控制全球培訓(xùn)教材ProcessCapability-Whatisit?ProcessCapabilityisameasureoftheinherent

capabilityofamanufacturingprocesstobeabletoconsistentlyproducecomponentsthatmeettherequireddesignspecificationsProcessCapabilityisdesignatedbyCpandCpkProcessPerformanceisameasureoftheperformanceofaprocesstobeabletoconsistentlyproducecomponentsthatmeettherequireddesignspecifications.ProcessPerformanceincludesspecialcausesofvariationnotpresentinProcessCapabilityProcessPerformanceisdesignatedPpandPpkNokia生產(chǎn)過程控制全球培訓(xùn)教材WhyMakeProcessCapabilityStudiesLSL(lowerspecificationlimit)10,7USL(upperspecificationlimit)10,9Nominal10,80,1Thispartiswithinspec.ThetoolwouldbeapprovedifonlythispartwasmeasuredThesepartsareoutofspecandcouldbeapprovedifonlyonegoodpartwasmeasuredAprocesscapabilitystudywouldrevealthatthetoolshouldnotbeacceptedWhenadimensionneedstobekeptproperlywithinspec,wemuststudytheprocesscapability….butstillthisisnoguaranteefortheactualperformanceoftheprocessasitisonlyaninitialcapabilitystudyNokia生產(chǎn)過程控制全球培訓(xùn)教材E1.5

E1

E2

E3

E4

E5TheNokiaProcessVerificationProcessBlackdiamondstobefixedbyE3(oftenachangeofawhitediamond)ProposalforblackdiamondstobediscussedwithSupplier.Max:105,85OngoingProcessControl(SPC)TolerancesappliedtodrawingType1FunctionalCharacteristics-1part/cavitymeasuredformeasurementreportWhitediamonds(s)tobeagreedWhitediamonds(s)tobediscussedwithsupplier10parts/cavitymeasuredformeasurementreportCapabilitystudy:Requirement:CpandCpk>1.67byE3.Quantitiestobeagreedwithsupplier.Minimum5partspr1/2hourin10hoursmeasuredforeachcavity=100parts.Canvarydependingontoolcapacity,e.g.stampedparts(seeDMY00019-EN)Nokia生產(chǎn)過程控制全球培訓(xùn)教材Section2.Population,SampleandNormalDistributionNokia生產(chǎn)過程控制全球培訓(xùn)教材TheBellShaped(Normal)DistributionSymmetricalshapewithapeakinthemiddleoftherangeofthedata.Indicatesthattheinputvariables(X's)totheprocessarerandomlyinfluenced.Nokia生產(chǎn)過程控制全球培訓(xùn)教材“PopulationParameters”

=Populationmean

=PopulationstandarddeviationPopulationversusSamplePopulationAnentiregroupofobjectsthathavebeenmadeorwillbemadecontainingacharacteristicofinterestSampleThegroupofobjectsactuallymeasuredinastatisticalstudyAsampleisusuallyasubsetofthepopulationofinterestPopulationSample“SampleStatistics” x=Samplemean s=SamplestandarddeviationNokia生產(chǎn)過程控制全球培訓(xùn)教材TheNormalDistributionNokia生產(chǎn)過程控制全球培訓(xùn)教材WhatMeasurementsCanBeUsedtoDescribeaProcessorSystem?Example:1

=52

=73

=44

=25

=6mean(average)ordescribesthelocationofthedistributionμ(mü),ameasureofcentraltendency,isthemeanoraverageofallvaluesinthepopulation.Whenonlyasampleofthepopulationisbeingdescribed,meanismoreproperlydenotedas

(x-bar):Nokia生產(chǎn)過程控制全球培訓(xùn)教材Example:1

=52

=73

=44

=25

=6Themostsimplemeasureofvariabilityistherange.Therangeofasampleisdefinedbyasthedifferencebetweenthelargestandthesmallestobservationfromsamplesinasub-group,e.g.5consecutivepartsfromthemanufacturingprocess.WhatMeasurementsCanBeUsedtoDescribeProcessvariation?Nokia生產(chǎn)過程控制全球培訓(xùn)教材sST-oftennotatedas

orsigma,isanothermeasureofdispersionorvariabilityandstandsfor“short-termstandarddeviation”,whichmeasuresthevariabilityofaprocessorsystemusing“rational”sub-grouping.where

istherangeofsubgroupj,Nthenumberofsubgroups,andd2*dependsonthenumberNofsubgroupsandthesizenofasubgroup(seenextslide)WhatMeasurementsCanBeUsedtoDescribeProcessvariation?Nokia生產(chǎn)過程控制全球培訓(xùn)教材d2*valuesforSSTWhere:N=no.ofsub-groups,n=no.ofsamplesineachsub-groupd2*d2Typical:N=20&n=5Nokia生產(chǎn)過程控制全球培訓(xùn)教材

x3

x2

x1

x10x_tExample:WhatMeasurementsCanBeUsedtoDescribeProcessvariation?Nokia生產(chǎn)過程控制全球培訓(xùn)教材TheDifferenceBetweenSSTandsLT!!meanTimeDimensionShorttermStandardDeviationLongtermStandardDeviationSubgroupsizen=5NumberofsubgroupsN=7TRENDSubgroupNo.1Nokia生產(chǎn)過程控制全球培訓(xùn)教材ThedifferencebetweenthestandarddeviationssLTandsSTgivesanindicationofhowmuchbetteronecandowhenusingappropriateproductioncontrol,likeStatisticalProcessControl(SPC).Short-termstandarddeviation:Long-termstandarddeviation

:ThedifferencebetweensSTandsLTNokia生產(chǎn)過程控制全球培訓(xùn)教材ThedifferencebetweensSTandsLTThedifferencebetweensLTandsST

isonlyinthewaythatthestandarddeviationiscalculatedsLTisalwaysthesameorlargerthansSTIfsLTequalssST,thentheprocesscontroloverthelonger-termisthesameastheshort-term,andtheprocesswouldnotbenefitfromSPCIfsLTislargerthansST,thentheprocesshaslostcontroloverthelonger-term,andtheprocesswouldbenefitfromSPCThereliabilityofsLTisimprovedifthedataistakenoveralongerperiodoftime.AlternativelysLTcanbecalculatedonseveraloccasionsseparatedbytimeandtheresultscomparedtoseewhethersLTisstableNokia生產(chǎn)過程控制全球培訓(xùn)教材Exercise1:SampleDistributions1.InExcelfile"Dataexercise1.xls"

youfind100measurementsbeingtheresultofacapabilitystudy.Thespecificationforthedimensionis15,16,01

2.Howwelldoesthesamplepopulationfitthespecification,e.g.shouldweexpectanypartsoutsidespec?3.Mentionpossibleconsequencesofhavingapartoutsidespec.4.Mentionpossiblecausesofvariationforparts.5. Calculatethesamplemeanandsamplestandarddeviationforthe100measurements.UsetheaverageandstdevfunctionsExcel.Nokia生產(chǎn)過程控制全球培訓(xùn)教材Section3.CpandCpkConceptNokia生產(chǎn)過程控制全球培訓(xùn)教材DefiningCpandPpSamplemeanProcessvariation6*sUSL-LSLLSLUSLNominaldimThetoleranceareadividedbythetotalprocessvariation,irrespectiveofprocesscentring.Nokia生產(chǎn)過程控制全球培訓(xùn)教材DefiningCpkandPpkSamplemeanProcessvariation3sProcessvariation3sMean-LSLUSL-MeanLSLUSLNominaldimCpkandPpkIndexesaccountalsoforprocesscentring.Nokia生產(chǎn)過程控制全球培訓(xùn)教材WhatistheDifferenceBetweenCpandCpk?TheCpindexonlyaccountsforprocessvariabilityTheCpkIndexaccountsforprocessvariabilityandcenteringoftheprocessmeantothedesignnominalTherefore,Cp

CpkNOTE:SameappliesalsoforPpandPpkCp=Cpk(bothlow)LSLUSLMean=NominalRejectpartsRejectpartsCphigh,Cpklow

Processshouldbeoptimized!NominalLSLMeanUSLRejectpartsNokia生產(chǎn)過程控制全球培訓(xùn)教材WhatDoTheseIndexesTellUs??Simplenumericalvaluestodescribethequalityoftheprocess>>ThehigherthenumberthebetterRequirementforCpandCpkis1.67min.RecommendationforPpandPpkis1.33min.Thisleavesussomespaceforthevariation,i.e.asafetymarginAreweabletoimproveourprocessbyusingSPC?Ifindexislow,followingthingsshouldbegivenathought:IstheproductdesignOK?Aretolerancelimitssetcorrectly?Tootight?Istheprocesscapableofproducinggoodqualityproducts?Processvariation?DOErequired?Isthemeasuringsystemcapable?(SeeGageR&R)Nokia生產(chǎn)過程控制全球培訓(xùn)教材Cpk-Witha2-sigmasafetymargin-3sST+3sSTLCLUCLLSLUSLMeanvalue=NominalvalueorTargetRequirementforCpandCpkis

1.67min.1.67isaratioof=5/3or10/6.6*standarddeviation10*standarddeviation2*standarddeviation2*standarddeviationNokia生產(chǎn)過程控制全球培訓(xùn)教材Cpk<1.67theprocessNOTCAPABLEAcceptabilityofCpkIndex

Cpk>=1.67theprocessisCAPABLECpk>=2.0theprocesshasreachedSixSigmalevelNokia生產(chǎn)過程控制全球培訓(xùn)教材WhatDoTheseIndexesTellUs??IfCp=Cpk,IfPp=Ppk,IfCpk<Cp,IfPpk<Pp,IfCp=Pp,IfCpk=Ppk,IfPp<Cp,IfPpk<Cpk,…thenprocessisaffectedbyspecialcauses.InvestigateX-bar/R-chartforout-of-controlconditions.SPCmaybeeffective…thenprocessisnotaffectedbyspecialcausesduringthestudyrun.SPCwouldnotbeeffectiveinthiscase…thenprocessperfectlycentred…thenprocessnotcentred(checkprocessmeanagainstdesignnominal)Nokia生產(chǎn)過程控制全球培訓(xùn)教材CpandCpkIndicesandDefects

(bothtailsofthenormaldistribution)Pp=Ppk=1,3363ppmdefects=0,006%Cp=Cpk=1,670,6ppmdefects=0,00006%Note:PpmrejectratescalculatedfromCp&CpkarebasedontheshorttermvariationwhichmaynotrepresentthelongtermrejectrateNokia生產(chǎn)過程控制全球培訓(xùn)教材TheEffectsofCpkandCponFFRNokia生產(chǎn)過程控制全球培訓(xùn)教材Exercise2:CpandCpkCalculateCpandCpkforthe100measurementsinthefile"Dataexercise1.xls"DeterminetheapproximateCpandCpkforthe4samplepopulationsonthefollowingpageShouldactionsbemadetoimprovetheseprocesses.Ifyes,which?Nokia生產(chǎn)過程控制全球培訓(xùn)教材EstimateCpandCpk?Thewidthofthenormaldistributionsshowninclude±3*sLSLUSLA)LSLUSLB)LSLUSLC)USLLSLD)Nokia生產(chǎn)過程控制全球培訓(xùn)教材EstimateCpandCpk?-A)LSLUSLA)MeanandnominalUSL-LSL6*sUSL-MeanMean-LSL3*sNokia生產(chǎn)過程控制全球培訓(xùn)教材EstimateCpandCpk?-B)LSLUSLB)NominalMeanUSL-LSL6*sUSL-MeanMean-LSL3*sNokia生產(chǎn)過程控制全球培訓(xùn)教材EstimateCpandCpk?-C)LSLUSLC)NominalMeanUSL-LSL6*sUSL-MeanMean-LSL3*sNokia生產(chǎn)過程控制全球培訓(xùn)教材EstimateCpandCpk?-DUSLLSLD)NominalMeanUSL-LSL6*sUSL-MeanMean-LSL3*sNokia生產(chǎn)過程控制全球培訓(xùn)教材Section4.UseoftheNMPDataCollectionSpreadsheetNokia生產(chǎn)過程控制全球培訓(xùn)教材ExampleofhowtoCollectData

1. Runinandstabiliseprocess2. Notethemainparametersforreference3. Whentheprocessisstablerunthetoolfor10hours3. Take5partsoutfromeachcavityeveryhalfhourandmarkthemwithtime,dateandcavity.Total20setsof5partsfromeachcavitymustbemade,oraccordingtoagreement.4. Afterthelastsamplelotnotethemainprocessparametersforreference5. Measureandrecordthemainfunctionalcharacteristics(whitediamonds)6. FilldataintotheNMPdatacollectionspreadsheet7. Analyse!SeeDMY00019-ENClassificationandMarkingofFunctionalCharacteristicsTimeDimensionSubgroupsizen=5NumberofsubgroupsN=200,5hoursbetweensamplestakenNote:Forclarity,on