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CapabilityAnalysis过程能力分析MPTConfidentialPage2测量阶段流程图流程图(Processmapping)C&E矩阵初步分析可能因子FMEA进一步分析可能因子测量系统定义,MSAY的稳定性判定,过程能力分析二次FMEA可能因子总结分析阶段定义阶段鱼骨图(Fishbone)MPTConfidentialPage3LearningObjectives学习目的1.ProcessControlvsProcessCapability过程控制和过程能力1.ProcessCapability过程能力:①Specification,ProcessandControlLimits.规格,过程和控制界限②ProcessPotentialvsProcessPerformance过程潜在的和实际的表现2.Short-TermvsLong-TermProcessCapability3.短期和长期过程能力4.“SixSigma”Quality;“6Sigma”水平;5.IntroductiontoZ-scoreZ-值介绍6.ProcessCapabilityforNon-NormalData非正态分布的过程能力①Cycle-Time(ExponentialDistribution)循环时间(指数分布)②RejectRate(BinomialDistribution)不合格(剔除)率(二项式分布)③DefectRate(PoissonDistribution)缺陷率(泊松分布)MPTConfidentialPage4ProcessControlvsProcessCapability过程控制和过程能力1.ProcessControl过程控制Meanstheprocessisoperatinginstatisticalcontrol,i.e.commoncausesaretheonlysourceofvariation.意味是过程在稳定状态下生产,也就是说,一般原因(偶然原因)是变异的唯一原因Refersto“voiceoftheprocess”,i.e.oneonlyneedsdatafromtheprocesstodetermineifaprocessisincontrol.起源于”过程的声音”,也就是说,唯一来源于过程的数据来判定过程是否受控.Trackperformanceoftheprocesstoverifyifitformsastabledistributionovertime,typicallywithacontrolchartwithcontrollimitscomputedfromtheprocessdataonly.随着时间过去,反馈过程的表现来验证它是否来自于一个稳定的分布,一般地,利用从过程数据计算控制界限的控制图来完成.Justbecauseaprocessisincontroldoesnotnecessarilymeanitisagoodprocess.仅仅因为过程受控并不一定说它是个好过程.MPTConfidentialPage52.ProcessCapability过程能力The“goodness”ofaprocessismeasuredbyprocesscapability过程的“好坏”是过程能力测量的Compares“voiceoftheprocess”with“voiceofthecustomer”,whichisgivenintermsofspecs.orrequirements比较“过程声音”和“客户声音”,哪一个是根据规格或需要给出的?Measureshowwellastabledistribution(processincontrol)matchesupwithcustomer’sspecs.测量一个稳定的分布(过程受控)符合客户规格的程度.ProcessControlvsProcessCapability过程控制和过程能力首先判定过程稳定,确定数据分布是正态的,再计算过程能力和西格码质量水平.MPTConfidentialPage6WhatisCapability过程能力是....•Whenprocessisundercontrol,capabilityisdecidedbycustomerdemandandprocessperformance(Productorservicequalityshiftingdegree).Themoretheprocessmeetsthecustomerneed,thebetterthecapabilitywillbe.•过程在受控状态下时,客户要求与过程表现(产品品质或服务的品质变动程度)的比值,如果过程表现越能满足客户要求,则过程能力越充分,反之则不足.LSLUSLMPTConfidentialPage7ProcessCapability过程能力ProcessCapabilitystudiescan过程能力研究可以:•indicatetheconsistencyoftheprocessoutput•显示过程输出的稳定性•indicatethedegreetowhichtheoutputmeetsspecifications•表明输出满足规格的程度•beusedforcomparisonwithanotherprocessorcompetitor•可以与另一过程或竟争对手相比较MPTConfidentialPage8ProcessVariation过程变异ProcessVariationistheinevitabledifferencesamongindividualmeasurementsorunitsproducedbyaprocess.过程变异是不可避免的差别在单个测量或过程生产单位之间.SourcesofVariation变异的来源:•withinunit产品内(positionalvariation)位置的变异•betweenunits单位之间(unit-unitvariation)产品-产品的变异•betweenlots产品批之间(lot-lotvariation)批—批的变异•betweenlines生产线之间(line-linevariation)线---线之间的变异•acrosstime不同时间(time-timevariation)时间--时间的变异•measurementerror测量误差(repeatability&reproducibility)重复性和再现性MPTConfidentialPage9TypesofVariation变异的类型1.PositionalVariation位置变异Sameprocess,variationatdifferinglocationssimultaneously:相同的过程,随不同位置而产生的变异Temperaturevariationsinsideathermalchamber温度变异在一个烘箱中Cavity-to-cavityvariationsinaninjectionmold洞坑差别在一个注塑模中2.CyclicalVariation重复误差Sequentialrepetitionsofaprocessoverfairlyshorttime,say,lessthan15mins:在一定短的时间内某过程的连续重复,比方说,少于15分钟:Variationsbetweenconsecutivebatchesofaprocess同一过程的连续批次之间的变异Differencesfromlottolotofrawmaterials不同批次原材料之间的差别3.TemporalVariation时间的变异Variationsoverlongerperiodsoftime,suchaseveralhours,daysorweeks.长期的变异,例如几个小时,几天或几个星期.MPTConfidentialPage10InherentorNaturalVariation固有或自然的变异•Duetothecumulativeeffectofmanysmallunavoidablecauses•归因于许多小的,不可避免的因素共同的结果•Aprocessoperatingwithonlychancecausesofvariationpresentissaidtobe“instatisticalcontrol”•如果一个过程运行时只存在固有原因变异的作用,就说它处在“统计控制状态”.TypesofVariation变异的类型一般原因MPTConfidentialPage11SpecialorAssignableVariation特殊的可查明的变异•Maybedueto可能归因与:•a)improperlyadjustedmachine不正确的调机b)operatorerror员工错误c)defectiverawmaterial有缺陷的原材料•Aprocessoperatinginthepresenceofassignablecausesofvariationissaidtobe“out-of-control”.•如果一个过程运行时存在可指出原因变异,则称该过程“失控TypesofVariation变异的类型异常原因MPTConfidentialPage12ProcessCapabilityvsSpecificationLimits过程能力和规格界限a)b)c)a)Processishighlycapableb)Processismarginallycapablec)Processisnotcapablea)过程能力高b)过程能力一般c)过程能力差MPTConfidentialPage13ThreeTypesofLimits三种类型的界限SpecificationLimits(LSLandUSL)•createdbydesignengineeringinresponsetocustomerrequirementstospecifythetoleranceforaproduct’scharacteristicProcessLimits(LPLandUPL)•measuresthevariationofaprocess•thenatural6limitsofthemeasuredcharacteristicControlLimits(LCLandUCL)•measuresthevariationofasamplestatistic(mean,variance,proportion,etc)规格界限(LSLandUSL)·由设计工程部门根据客户要求确定的产品性能公差。过程界限(LPLandUPL)．•用来测量过程的变异．·为所测量特性的自然公差(六倍标准差(6δ))界限控制界限(LCLandUCL)·用来测量样本统计量的变异(均值，方差．比例等)MPTConfidentialPage14DistributionofIndividualValues(x)DistributionofSampleAverages(x)ThreeTypesofLimits三种类型的界限单值分布样本均值分布MPTConfidentialPage15ProcessCapabilityIndices过程能力指数Twomeasuresofprocesscapability:过程能力的两种测量•ProcessPotential过程潜力Cp•ProcessPerformance过程表现CpuCplCpkMPTConfidentialPage16ProcessPotential过程潜力TheCpindexassesseswhetherthenaturaltolerance(6)ofaprocessiswithinthespecificationlimits.工序能力指数Cp用以评价是否一