ProcessCapability制程能力

(ForOnePart,ProcessStep,orPerformanceParameter)

(對(duì)產(chǎn)品,工序,或表現(xiàn)參數(shù))1Agenda

Objectives目標(biāo)CapabilityAssessment能力評(píng)估OurProblem-SolvingOption我們問題對(duì)策的選擇CapabilityAnalysisProcessMap能力分析過程圖CapabilityAnalysis,Steps.能力分析、步聚TheZ-Scoreor“SigmaValue”z-值或sigma值PPM’s(PartsPerMillion)ppm`s(每百萬單位數(shù))Yield,converting%Non-conforming

unitstoYield產(chǎn)出，不良單位百分比轉(zhuǎn)換成產(chǎn)出ProcessCapabilityIndices:Cp,Cpk,Pp,Ppk制程能力指數(shù)：Cp,Cpk,Pp,Ppk2CapabilityAssessment

能力評(píng)估What’sthepurposeofassessingyourproduct/processcapability?產(chǎn)品/制程能力評(píng)估的目的是什么？Establishmentofabaselinetomeasureimprovementagainst.

確認(rèn)測量改善效果的基準(zhǔn)Identificationofthenatureofyourproblem.問題類型的辨認(rèn)Iscenteringtheissuewithyouroutputofinterest(Y)?輸出(Y)問題是否處于中心？Isitprocessvariationinyouroutputofinterest(Y)?輸出(Y)問題是否過程變異?Isthespecificationforyourprocessoutput(Y)correct?輸出(Y)問題是否在于規(guī)格正確？Isitacombination

ofcenteringandvariation?是否是中心和變異的綜合問題？3.Determinationofthegapbetweenwhereyourprocessisandwhereyouwantittobe(improvementassessment).確認(rèn)過程現(xiàn)狀與目標(biāo)狀態(tài)的差距(改善評(píng)估)3ProblemSolvingOptions問題解決對(duì)策Options對(duì)策CentertheMean均值處在中心ReduceVariation減少變異UpperSpecificationLimit上規(guī)格線mLowerSpecificationLimit下規(guī)格線TargetMeanCURRENT當(dāng)前ExcessiveVariation過大的變異OBJECTIVEmTargetMean目標(biāo)均值UpperSpecificationLimit上規(guī)格線LowerSpecificationLimit下規(guī)格線OBJECTIVE目標(biāo)mLowerSpecificationLimit下規(guī)格線TargetMean目標(biāo)均值UpperSpecificationLimit上規(guī)格線OBJECTIVE目標(biāo)MeanoutoftargetUpperSpecificationLimitmLowerSpecificationLimitTargetValueCURRENTUpperSpecificationLimit上規(guī)格線mLowerSpecificationLimit下規(guī)格線TargetMean目標(biāo)均值CURRENT當(dāng)前Meanoutoftarget中心偏離目標(biāo)4ProblemSolvingOptions問題解決對(duì)策M(jìn)ovetheSpec.Limits移規(guī)格線CentertheMeanandReduceVariation中心的均值并減少變異OBJECTIVE

目標(biāo)mLowerSpecificationLimit下規(guī)格線TargetMean目標(biāo)均值UpperSpecificationLimit上規(guī)格線IncorrectSpecificationCURRENTUpperSpecificationLimitmLowerSpecificationLimitTargetMeanCURRENT當(dāng)前OBJECTIVEmLowerSpecificationLimit下規(guī)格線TargetMean目標(biāo)均值UpperSpecificationLimit上規(guī)格線OBJECTIVE目標(biāo)ExcessiveVariationandMeanoutoftarget過多的變異及均值偏離目標(biāo)UpperSpecificationLimitCURRENT當(dāng)前mLowerSpecificationLimitTargetMeanOptions對(duì)策5CapabilityAnalysis-ProcessMap

能力分析-過程圖z-scorez-值Z-levelZ-水平Partspermillion,每百萬零件數(shù)Ppm,DPMOProcesscapability過程能力Cp,Cpk,Pp,PpkYield產(chǎn)出1.SelecttheOutput(Y)toimprove選擇輸出(y)來改善2.Verifythemeasurementsystem測量系統(tǒng)分析(GR&R)3.Verifycustomerrequirements確認(rèn)客戶要求7.Calculatetheappropriatedatametrics數(shù)據(jù)處理4.Validatespecificationlimits確認(rèn)規(guī)格界線5.Collectsampledata收集樣品資料(IsitLTorST?是長期或短期？)6.AssessData數(shù)據(jù)評(píng)估(DescriptiveStats–Normality?描術(shù)統(tǒng)計(jì)-正態(tài))?6Oneoftheprocessesinyourcompanyisrotordiecasting過程之一是轉(zhuǎn)子模鑄造.Theserotorsareusedinelectricmotorsproducedatyourfacility.Toestablishyourprocesscapabilityyouhaverandomlycollected30castedrotorsoverthelastfewdays.這些轉(zhuǎn)子用在你們?cè)O(shè)備的電動(dòng)機(jī)里，隨機(jī)抽取30件最近幾天澆注的轉(zhuǎn)子評(píng)估制程能力CapabilityAnalysisExample能力分析舉例OUTSIDEDIM.外經(jīng)INTERNALDIM.內(nèi)徑7CapabilityAnalysis–Steps

能力分析-步聚Step1:Selecttheoutput(s)(Y’s)toimprove.步驟1：選擇輸出(Y)來改善(轉(zhuǎn)子外表面直徑)

(Outsiderotordiameter.)

Selectfrom:選擇途徑Businesscase市場需要Primary/Secondarymetric.關(guān)鍵/次要尺寸Importantinputtocontrol.重要輸入(X)控制Step2:Verifythatthemeasurementsystemiscapable.步驟2：確認(rèn)測量系統(tǒng)是可用的8CapabilityAnalysis,Steps

能力分析-步聚Step3:Verifycustomerrequirements.

步驟3：確認(rèn)客戶要求Consultthecustomer(Internal/External)客戶溝通(內(nèi)部/外部)Makesurerequirementsare:Understood,Reasonable,Measurable,Achievable.確保要求是：清楚、合理、可測量、可達(dá)到。Step4:Validatethespecification確認(rèn)規(guī)格Isthedefinitionofthespecificationimportant?規(guī)格的精確度是否重要？Wheredidthespecificationcomefrom?規(guī)格的來源？Drawing?圖低？Processprocedure?工藝程序？Customer?客戶？9Step5:CollectaDataSample

步驟5：收集數(shù)據(jù)樣品Wecollectedourdatafromcastrotorsproducedthisweekusingthethreemachineswehaveinourprocess.WehavedeterminedthatwehaveShort-Termdata.我們從生產(chǎn)的澆注轉(zhuǎn)子收集數(shù)據(jù)，在制程中我們使用了3臺(tái)機(jī)器，我們確定使用短期數(shù)據(jù)Definitions:定義：Short-Term–STsampledatacapturesasmallportionof totalvariationthataprocessmayexhibit.短期-短期樣品數(shù)據(jù)來自過程可能出現(xiàn)所有變異中的一小部分Long-Term–LTsampledatacapturesthemajorityof variationthataprocesswillexhibit.長期-長期樣品數(shù)據(jù)來自過程可能出現(xiàn)所有變異中的大部分Youastheprocessexpertsshouldbeinapositiontodetermineifyouaredealingwithshort-termorlong-termdata.作為一個(gè)工藝專家，你有能力決定是用短期或長期數(shù)據(jù)10SampledataisverifiedthatitfollowsaNormaldistribution.Thedataisanalyzedforinsighttohaveacluewhyisdeviatingfromnormaldistribution(outliers,distributionshape...)樣品數(shù)據(jù)證實(shí)是符合正態(tài)分布，數(shù)據(jù)分析觀察到存在一些不合正態(tài)分布(超出正態(tài)分布輪廓線)Step6:AssessData步驟6：數(shù)據(jù)評(píng)估P-value=>0.05,datacanbeconsideredNormallydistributedP值=>0.05，數(shù)據(jù)可認(rèn)為是正態(tài)分布的11Step7:CalculateAppropriateDataMetrics步驟7：計(jì)算適當(dāng)數(shù)據(jù)值

Thesearethemetricsbeingusedinindustry.Understandinghowto

convertfromonetoanotherwillimproveourcommunication.這些是用在工業(yè)中的數(shù)據(jù)值，了解相互之間轉(zhuǎn)換會(huì)改善我們的溝通z-scorez-值ZLevelZ水平Parts

permillion,每百萬部件數(shù)Ppm,DPMOProcesscapability過程能力Cp,Cpk,Pp,PpkYield產(chǎn)出RTY直通率PROCESSCAPABILITYMETRICS過程能力12Thez-scorez值Thez-score,indicateshowfarapointofinterest,isawayfromthesamplemean,measuredinstandarddeviationsunits(z).z值代表從均值到關(guān)注點(diǎn)的距離，用多少了標(biāo)準(zhǔn)差(z)表示。Typically,thepointofinterestisthespecificationlimit.

特別情況，關(guān)注點(diǎn)在規(guī)格界線上。Knowinghowmanystandarddeviationsawaythespecificationlimitiswillallowustodeterminetheamountofproductthatfallsoutsidethespecificationlimit.知道距離規(guī)格線多少標(biāo)準(zhǔn)差，我們就能確定不合格產(chǎn)品的數(shù)量TheSigmaLevel(Z-Level)istheequivalentz-scorewhenaddingz-scoreUSLandz-scoreLSL)

SIGMA水平(Z-水平)等于Z-值、Z-值是上控制線和下控制線Z-值相加的和。TheZ-LevelisusedasabenchmarkontheroadtoSixSigma.Z-水平是用作通向六西格瑪?shù)囊粋€(gè)基準(zhǔn)。13Thez-scoreZ-值

Let’scalculatesomez-scores/Zlevelsforthefollowingcases:我們來用下面一些例子計(jì)算Z值/Z水平：Case1:舉例1：Non-conformingproductattheLowerSpecLimit(LSL):低于下規(guī)格線(LSL)的不格產(chǎn)品：3,500PPM’sNon-conformingproductattheUpperSpecLimit(USL):高于上規(guī)格線(USL)的不格產(chǎn)品：500PPM’s.Case2:舉例2：Non-conformingproductattheLSL:1,250PPM’s

低于下規(guī)格線(LSL)的不格產(chǎn)品：1,250

PPM’s

Non-conformingproductattheUSL:2,250PPM’s高于上規(guī)格線(USL)的不格產(chǎn)品:2,250PPM’s14PPM’s(PartsPerMillion)每百萬中部件數(shù)

Convertingz-scoreto%Non-conformingunits

toPPM

Z值、不合格百分比、PPM的轉(zhuǎn)換Withthez-scoreweareabletoestimateproportionofnon-conformingunits.我們用Z值能得到不合格單位比例Multiplyingtheproportionofnon-conformingunits

by100weexpressitin%defective.不合格單位比例乘100，我們用不合格百分率表示ThisiswhatwedotoexpressitinPPM’s:這是我們PPM表達(dá)的原因=不合格%/100*1,000,00027,500ppm’s=不合格率*10,000=27,500ppm’s15Yield產(chǎn)出Converting%Non-conformances

toYield不合格百分率轉(zhuǎn)換至產(chǎn)出Yieldisrelatedtoa%ofgoodpieces.產(chǎn)出是合格件數(shù)的百分率。Thisishowitiscalculated:下面是關(guān)于怎樣的計(jì)算。Yield=(1–Proportionofnon-conforming

units)*100Yield=(1-不合格單位比例)*100Yield=(1-

.0251)*100=97.49%16USLLSLProcessRange制程范圍SpecificationRange規(guī)格范圍Target目標(biāo)+3s-3sProcessCapabilityIndices:

制程能力指數(shù)

Cp,Cpk,Pp,PpkProcessCapabilityisatermtoexpresstheabilityofaprocesstomeetthespecification.制程能力是表達(dá)過程滿足規(guī)范的能力ThisabilitywaschosentobemeasuredbytheproportionoftheProcessRangethatfallswithintheSpecificationRange.這個(gè)能力用來判定制程范圍落在規(guī)格范圍的比例Itwasalsochosentoconsiderthevariationcontainedon–3sand+3s(CpandPp)todefinetheProcessRange.它也用來考慮用包含在–3s和+3s

之間的變異(Cp和Pp)來決定制程范圍Capability=DesignRange

設(shè)計(jì)范圍能力ProcessRange制程范圍17CpandCpkarecapabilityindicesandmeasuresthebestyourprocesscan

be,onceprocessvariationit’sreducedtoitsminimum.

Cp和Cpk

是描術(shù)過程能達(dá)成最佳值的好指標(biāo)，達(dá)成過程變異的最小。CpiscalledProcessPotentialorProcessEntitlement.Cp是描述過程或潛在最佳值Cpmeasuresthebestyourprocesscanbewithoutconsideringprocessmeanlocation.Cp描述過程中最佳值、沒有考慮過程均值的位置Itusesthewithinsubgroupstd.Deviation它使用短期子群的標(biāo)準(zhǔn)差SpecificationRange規(guī)格范圍ProcessRange過程范圍(+/-3s)0.7575ProcessCapabilityIndices:過程能力指數(shù)

Cp,Cpk,Pp,Ppk18Cpkconsidersthelocationofthemean

relativetothespecificationlimits

Cpk考慮了均值的位置與規(guī)格線之間相對(duì)關(guān)系TocalculatetheCpkusetheUpperorLowerspecificationlimits,whicheverisclosesttotheprocessmean.

用上或下規(guī)格線計(jì)算

Cpk是否是離過程均值最近

Cpkusesthewithinstd.Deviation.

Cpk

使用短期標(biāo)準(zhǔn)差SpecificationRange規(guī)格范圍ProcessRange(3s)過程范圍=3.22696-3.226=3*0.00044=0.7272ProcessCapabilityIndices:過程能力指數(shù)

Cp,Cpk,Pp,Ppk19PpandPpkareperformance

indices,measureyourprocesscurrentperformancePp和Ppk

是長期能力指數(shù)、描述當(dāng)前過程表現(xiàn)PpandPpkformulasarethesameforCpandCpk,butusingtheOverallstddev(s)insteadofthewithin

stddev(s).Pp和Ppk計(jì)算公式與Cp和Cpk相同，但使用長期標(biāo)準(zhǔn)差代替短期標(biāo)準(zhǔn)差ProcessCapabilityIndices:過程能力指數(shù)

Cp,Cpk,Pp,Ppk20

LongTerm長期

ShortTerm短期Youastheprocessexpertshouldbeinapositiontodecideifyourdatacapturesshortorlongtermprocessvariation.作為工藝專家你能確定你所獲得的數(shù)據(jù)是長期或短期變異Ifthesourcesofvariationcapturedinyourdataareshortterm,thentheProcessCapabilityIndiceswillbeshortterm如果獲得數(shù)據(jù)變異是短期的，那么制程能力指數(shù)是短期的Ifthesourcesofvariationcapturedinyourdataarelongterm,thentheProcessCapabilityIndiceswillbelongterm.如果獲得數(shù)據(jù)變異是長期的，那么制程能力指數(shù)是長期的ProcessCapabilityIndices:過程能力指數(shù)Cp,Cpk,Pp,PpkProcessCapabilityIndices:過程能力指數(shù)

Cp,Cpk,Pp,PpkProcessCapabilityIndices:過程能力指數(shù)

Cp,Cpk,Pp,Ppk21CapabilityIndices:AnimprovementRoadmap能力指數(shù)：一個(gè)改進(jìn)的方向MeanCentering均值移中心

MeanCentering.均值移中心Whattodotoimprove?改善做什么Goal:目標(biāo)：Ppk=2ChangeProces/Technology工藝/技術(shù)更新ReduceVariationThebestyoucouldbe,withtheexistingprocess!當(dāng)前工藝你能做到的

ReduceVariation減少變異ReduceVariationandMeanCenteringCpk=0.5Cp=1.4Ppk=0.3Pp=0.922ProcessCapabilityIndices:過程能力指數(shù)

Cp,Cpk,Pp,PpkMinitab’sprimaryoutputonProcessCapability.Minitab過程能力的主要輸出23ProcessCapabilityIndices:過程能力指數(shù)

Cp,Cpk,Pp,PpkSpecLimitsandStatisticsusedtocalculateCapabilityIndices用來計(jì)算能力指數(shù)的規(guī)格值和統(tǒng)計(jì)表ObservedPPM’sPerformancewiththedatacollectedonthestudy用收集的數(shù)據(jù)獲得的ppm值ProcessPotentialindicesthatmeasuresthebestyourcurrentprocesscouldbe..過程長期潛在能力

ExpectedPPM’swiththePotentialPerformanceofyourCurrent

Process當(dāng)前過程潛在ppmPerformanceIndicesthatmeasureyourcurrentprocess.過程長期能力

ExpectedPPM’swiththeActualPerformanceofyourCurrentProcess當(dāng)前過程實(shí)際ppm24ConversionsbetweenShort-Term

andLong-Term短期和長期之間轉(zhuǎn)換3.4ppmLSLUSL4.5sTOvertimeprocessshiftsby1.5stoeitherside長期過程漂移到另一邊1.5sTLSLUSLProcessCentered過程中心0ppm0ppm6s

6s

4.5s1.5s1.5sThestd.whenusingthesigmalevelmetricistoassumeshorttermvariation.使用sigma水平時(shí)，設(shè)想短期變異的標(biāo)準(zhǔn)25ConversionsbetweenShort-Term

andLong-TermforUnilateralProcesses短期和長期單邊過程之間轉(zhuǎn)換CpkSigmaLevel(st)PPM(st)SigmaLevel(lt)PPM(lt)0.51.566,810

0.00.0500,000

0.61.835,930

0.10.3382,090

0.72.117,860

0.20.6274,280

0.82.48,200

0.30.9184,060

0.92.73,470

0.41.2115,070

1.03.01,350

0.51.566,810

1.13.3480

0.61.835,930

1.23.6160

0.72.117,860

1.33.950

0.82.48,200

1.44.213

0.92.73,470

1.54.53

1.03.01,350

1.64.81

1.13.3480

1.75.1-

1.23.6160

1.85.4-

1.33.950

1.95.7-

1.44.213

2.06.0-

1.54.53

SHORTTERM短期LONGTERM長期PpkCpk