质量管理七大手法wurooney

QC7Tools第一页，共五十一页。Whatis7tools?ChecksheetLeveldiagramHistogramParetodiagramCause-and-effectdiagramScatterdiagramControlchart第二页，共五十一页。Importanceof7toolsWhy“MADEINJAPAN”---Automobile,electronic,chemical,exactitudeequipment,etc.Theconcept“QC7tools”israisedbyKaoruIshikawa.“QC7tools”playedanimportantpartinJapan’seconomicrecoveryanddevelopment.第三页，共五十一页。QC7Tools---CheckSheetWhatischecksheet?Atablewhichlistsoutallitemsneedchecking.Checksheetincludes,butnotlimitedto:diagnoses,questionnaire,record,statistics,etc.第四页，共五十一页。CheckSheet---KeypointsKeypoints:1.Verifytheitemstocheck;2.Verifythefrequencytocheck;3.Verifythepersonneltocheck.第五页，共五十一页。Implementprocedure1.Verifytheobject;2.Framethechecksheet;3.Checkandrecord;4.RequestaimprovementaimingattheNCitems5.Verifytheimprovement6.Summarizeperiodicallyandimprovepersistently.第六页，共五十一页。LevelDiagramWhatisleveldiagram?Sortallopinions,viewsorthoughtsbyspecifictopicandgroupthecollecteddataorinformation.第七页，共五十一页。Implementprocedure1.Identifythetopictostudy;2.Frametheleveldiagramandcollectdata;3.Sortthedatatovariouslevels;4.Analyzethedata.第八页，共五十一页。QC7Tools---HistogramWhatishistogram?Ahistogramisasimplefrequencydistribution.Itisaplotoftheactualdatashowingthedatavaluesversusthenumberofoccurrencesforeachvalue.第九页，共五十一页。JudgetheProcessCapability(Cp)fromthehistogramCpisjustOKCpisbetterthanspecCpisleantoleftCpisleantorightTooscatteredCp第十页，共五十一页。ImplementProcedure1.Collectdata;Forexample:GeardimensionproducedbyABCfactoryasbelow;specificationofthisgearis24.5±6mm:1234567891022.123.422.627.722.923.724.521.324.721.225.824.523.221.321.624.124.817.421.920.323.924.624.322.724.626.730.026.023.124.622.821.822.624.025.122.419.323.923.621.525.023.624.924.826.423.926.618.323.225.321.725.023.521.724.327.229.025.023.822.322.228.024.621.625.224.826.727.628.525.824.625.322.527.525.524.824.623.818.819.925.124.822.626.624.125.023.420.621.326.322.924.421.523.123.428.922.4第十一页，共五十一页。ImplementProcedure2.Counttherange:R=Xmax–Xmin=30.0-17.4=12.63.Setthegroup:Totaldata50-100100-250>250Groups6-107-1210-20Weset10groupsinthisexample.第十二页，共五十一页。Implementprocedure4.Verifytheminmeasurementunit:Itisdecidedbydecimaldigits.Minimummeasurementunitinthisexampleis0.1.5.Counth;h=R/10=12.6/10=1.26≈1.3第十三页，共五十一页。Implementprocedure6.Counttheupperlimitandlowerlimit:

Lowerlimitoffirstgroup=17.4-(minmeasurementunit/2)=17.4-0.1/2=17.35;

Lowerlimitof2ndgroup=17.35+1.3=18.65;DetailUpper/lowerlimit:

1stgroup:17.35-18.65;2ndgroup:18.65-19.953rdgroup:19.95-21.25;

……9thgroup:27.75-29.05;10thgroup:29.05-30.35第十四页，共五十一页。Implementprocedure7.Countmedian;Groupmedian=(Groupupperlimit+Grouplowerlimit)/21stgroupmedian=(17.35+18.65)/2=18.00Therestmaybededucedbyanalogy.第十五页，共五十一页。Implementprocedure8.Fillfrequencytable:groupUpper/lowerlimitvalueMedianFrequencies117.35-18.6518.002218.65-19.9519.303319.95-21.2520.605421.25-22.5521.9016522.55-23.8523.2020623.85-25.1524.5029725.15-26.4525.8012826.45-27.7527.108927.75-29.0528.4041029.05-30.3529.701第十六页，共五十一页。9.Drawhistogram.第十七页，共五十一页。Implementprocedure10.Analyzethehistogram.Thishistogrambelongstonormaldistribution,sotheprocessisconsideredasstable.第十八页，共五十一页。QC7tools---ParetoDiagramWhatisParetodiagram?Itisadiagrambasedonhistogramandusedtoidentifythe“criticalminor”.Paretodiagramcanbeusedtofindoutthemajorproblemonquality,cost,leadtime,safety(phenomenon);operator,machine,material,working(process).第十九页，共五十一页。ParetodiagramprocedureTakethedefectsfoundinafigureproductionforexample,total15854products,including216defectives.1.Collectdata2.Sortorder(descending),andcountaccumulativepercentage.第二十页，共五十一页。NoCategoryDefectDefect%AccumulativeDefect%1DirtMark7534.7%34.7%2Paintmigration4721.8%

56.5%

3Scratchmark3918.1%74.5%4Excessiveflash2813%87.5%5Insufficientglue177.9%95.4%6Whitemark73.2%98.6%7Other31.4%100.0%Total∑216100.0%100.0%第二十一页，共五十一页。Paretodiagramprocedure3.DrawXaxisandYaxisandmarkingscale.4.Drawhistogram.5.Drawaccumulativecurve.6.AnalyzeParetodiagramandtakecorrectiveaction.(Veryimportant).第二十二页，共五十一页。第二十三页，共五十一页。QC7tools---Cause-and-effectdiagramWhatisCause-and-effectdiagram?Itisatooltoanalyzethequalitycharacteristics(effect)andthepotentialfactortoeffectthecharacteristics(cause).第二十四页，共五十一页。Keypoints1.PersonnelfromdifferentDept;2.Analyzethecauseasdetailaspossible;3.Eachqualitycharacteristicneedsacause-and-effectdiagram;4.Verifytheproblemcanbesolvedornot;ifnot,subdividethecause.第二十五页，共五十一页。ImplementProcedure1.3-6variousdeptrepresentativestoformagroup;2.Topic:forexample,whydoesdimensionofgearvary?3.Drawouttherib,setthemajorcauseWhydoesdimensionofgearvary?ManMachineMaterialMethodEnvironment第二十六页，共五十一页。ImplementProcedure4.Findoutthedetailcauseandaddtothediagram(“BrainStorm”isrecommended);5.Markthecausethatmaybetherootoftheproblemandtakecorrectiveaction.第二十七页，共五十一页。Whydoesdimensionofgearvary?ManMachineMethodEnvironmentMaterialWrongoperationNotenoughtrainingNotimelycheckingPatrolintervaltoolongLaxdisciplineInsufficienthardnessVarioushardnessDifferentsuppliersImpurematerialEquipmentprecisionHardtoadjustInstablevoltagePoorfixtureNotimelymaintenanceNooperationinstructionNoiseTemperaturevariesInsufficientlight第二十八页，共五十一页。AnalysisFindout3majorproblems:1.Material:5differentsuppliers,notthesamequality,andnotstable;2.Person:Newworkers,notenoughtrainingresultsinwrongoperation;3.Method:NoWIorWIcontentnotrelatedtoactualwork.第二十九页，共五十一页。QC7Tools---ScatterDiagramWhatisscatterdiagram?AdiagramtofindoutwhetherthereisanyrelationshipbetweentwovariablesbyplottingthedatainX-Yaxlecoordinates.第三十页，共五十一页。TypesofscatterdiagramGenerallythereare4typesofscatterdiagram:Positivecorrelation(X↑,Y↑);Negativecorrelation(X↑,Y↓);Nocorrelation;Curvecorrelation.第三十一页，共五十一页。第三十二页，共五十一页。第三十三页，共五十一页。Keypoint1.Checkifthereisabnormaldot,findoutthecauseoftheabnormal;2.Datashouldbeenough(atleast>30)3.Asdataisalwaysvaryingduetoman,machine,material,method,environment,etc,weshouldsortthedatatoavoideffect.(leveldiagram).第三十四页，共五十一页。Implementprocedure1.Verifythe2variablestocheckandcollectthedata(atleast30groups);2.MarkthedotontheX-Ycoordinates;3.Judgetherelationship.第三十五页，共五十一页。ExampleScatterdiagramofmotorcontinuousoperationtime(T)andvelocity(V):Fig.4TVTVTVTVTV133073251325019210251712320828514244202042616533089300152372119727159431110270162312219128151530411264172252318529145629712257182182417830133第三十六页，共五十一页。QC7Tools---ControlChartWhatiscontrolchart?Controlchartsareameansofgraphingvariationpatternsfromprocessorproductcharacteristicssothatcorrectiveactionmaybetakenifrequired.第三十七页，共五十一页。NormaldistributionNormaldistributionisacurveofwhichthecenterisprotruded,twosidesofthecurvearelowerandsymmetrical.Weusetwoparametertodescribethenormaldistribution;μ(Meanvalue)andσ(standarddeviation).第三十八页，共五十一页。Parameterμandσμμ’μ<μ’Thenormalcurvemovestorightwhenμincreases.σ=2.5σ=1.0σ=0.4Qualitycharacteristicsbecomemorescatteredaccompaniedwiththeincreaseofthevalueofσ.第三十九页，共五十一页。TheoreticbasistosetUCLandLCLTheCentralline(CL)ofcontrolchartisthemeanvalue;UpperControlLimit(UCL)ismeanvalue+3σandLowerControlLimitismeanvalue-3σ.+3σ+2σ+1σ-1σ-2σ-3σCLUCLLCL第四十页，共五十一页。Relationshipbetweenσanddefectivepercentage1σ2σ3σ4σ5σ6σ69.77%30.87%6.68%6210PPM233PPM3.4PPM*Consideringinfluencesfromvariousfactors.*4.5σrepresents1350ppmdefectives.Comparing6σand3σ,defectivepercentagereduced20,000times!Motorolarequesthissupplierprovideproductswith6σquality;

第四十一页，共五十一页。3σand6σ…3σ6σMissing20,000E-mailperhourMissing7E-mailperhour15minutesunsafedrinkingwaterperday1minuteunsafedrinkingwaterper7months5000incorrectsurgicalperweek1.7incorrectsurgicalperweekTwicewronglandingonmainairportperdayOncewronglandingonmainairportper5years20,000wrongprescriptionperyear68wrongprescriptionperyear7hourspowercutpermonth1hourpowercutper34years第四十二页，共五十一页。Whichkindofcontrolcharttochoose?Howtochoosecontrolchart?TotalSizeAttributeCharacteristicCLPropertyX-RmChartSampleSizeUnitSizecChartuChartnpChartpChartSampleSizex–RChartx–σChartx–RChartVariablesAttributes1UnitDefectivesDefectsStableVaryfixedVaryxxn<1010≤n≤25第四十三页，共五十一页。Implementprocedure1.Collectdata;Generallydatashouldbe≥100.2.Groupthedata;Groupinto25groups,5data/group.3.Countxmeanandtotalxmean.x=(x1+x2+……+xn)/nx=∑xi/n第四十四页，共五十一页。Implementprocedure4.Countrange(R)ofeachgroupandmeanofrange(R);Ri=xmax–xmin;R=∑Ri/n5.CountUCL,CLandLCL.xChart:CL=x;UCL=x+A2R;LCL=x-A2RRChart:CL=R;UCL=D4R;LCL=D3R第四十五页，共五十一页。Implementproceduren2345678910D43.272.572.282.112.001.921.861.821.78D3000000.02A21.881.020.730.580.480.420.37