质量管理七大手法--wurooney

QC7ToolsWhatis7tools?ChecksheetLeveldiagramHistogramParetodiagramCause-and-effectdiagramScatterdiagramControlchartImportanceof7toolsWhy“MADEINJAPAN”---Automobile,electronic,chemical,exactitudeequipment,etc.Theconcept“QC7tools”israisedbyKaoruIshikawa.“QC7tools”playedanimportantpartinJapan’seconomicrecoveryanddevelopment.QC7Tools---CheckSheetWhatischecksheet?Atablewhichlistsoutallitemsneedchecking.Checksheetincludes,butnotlimitedto:diagnoses,questionnaire,record,statistics,etc.CheckSheet---KeypointsKeypoints:1.Verifytheitemstocheck;2.Verifythefrequencytocheck;3.Verifythepersonneltocheck.Implementprocedure1.Verifytheobject;2.Framethechecksheet;3.Checkandrecord;4.RequestaimprovementaimingattheNCitems5.Verifytheimprovement6.Summarizeperiodicallyandimprovepersistently.LevelDiagramWhatisleveldiagram?Sortallopinions,viewsorthoughtsbyspecifictopicandgroupthecollecteddataorinformation.Implementprocedure1.Identifythetopictostudy;2.Frametheleveldiagramandcollectdata;3.Sortthedatatovariouslevels;4.Analyzethedata.QC7Tools---HistogramWhatishistogram?Ahistogramisasimplefrequencydistribution.Itisaplotoftheactualdatashowingthedatavaluesversusthenumberofoccurrencesforeachvalue.JudgetheProcessCapability(Cp)fromthehistogramCpisjustOKCpisbetterthanspecCpisleantoleftCpisleantorightTooscatteredCpImplementProcedure1.Collectdata;Forexample:GeardimensionproducedbyABCfactoryasbelow;specificationofthisgearis24.5±6mm:1234567891022.123.422.627.722.923.724.521.324.721.225.824.523.221.321.624.124.817.421.920.323.924.624.322.724.626.730.026.023.124.622.821.822.624.025.122.419.323.923.621.525.023.624.924.826.423.926.618.323.225.321.725.023.521.724.327.229.025.023.822.322.228.024.621.625.224.826.727.628.525.824.625.322.527.525.524.824.623.818.819.925.124.822.626.624.125.023.420.621.326.322.924.421.523.123.428.922.420.126.226.4ImplementProcedure2.Counttherange:R=Xmax–Xmin=30.0-17.4=12.63.Setthegroup:Totaldata50-100100-250250Groups6-107-1210-20Weset10groupsinthisexample.Implementprocedure4.Verifytheminmeasurementunit:Itisdecidedbydecimaldigits.Minimummeasurementunitinthisexampleis0.1.5.Counth;h=R/10=12.6/10=1.26≈1.3Implementprocedure6.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:29.05-30.35Implementprocedure7.Countmedian;Groupmedian=(Groupupperlimit+Grouplowerlimit)/21stgroupmedian=(17.35+18.65)/2=18.00Therestmaybededucedbyanalogy.Implementprocedure8.Fillfrequencytable:groupUpper/lowerlimitvalueMedianFrequencies117.35-18.6518.002218.65-19.9519.303319.95-21.2520.605421.25-22.5521.9016522.55-23.8523.2020623.85-25.1524.5029725.15-26.4525.8012826.45-27.7527.108927.75-29.0528.4041029.05-30.3529.7019.Drawhistogram.Implementprocedure10.Analyzethehistogram.Thishistogrambelongstonormaldistribution,sotheprocessisconsideredasstable.QC7tools---ParetoDiagramWhatisParetodiagram?Itisadiagrambasedonhistogramandusedtoidentifythe“criticalminor”.Paretodiagramcanbeusedtofindoutthemajorproblemonquality,cost,leadtime,safety(phenomenon);operator,machine,material,working(process).ParetodiagramprocedureTakethedefectsfoundinafigureproductionforexample,total15854products,including216defectives.1.Collectdata2.Sortorder(descending),andcountaccumulativepercentage.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%Paretodiagramprocedure3.DrawXaxisandYaxisandmarkingscale.4.Drawhistogram.5.Drawaccumulativecurve.6.AnalyzeParetodiagramandtakecorrectiveaction.(Veryimportant).Paretodiagram75473928177334.70%56.50%74.50%87.50%95.40%98.60%100%01020304050607080DirtMarkPaintMigrationScratchMarkExcessiveFlashInsufficientglueWhiteMarkOtherDefectdescriptionDefectiveamount0%20%40%60%80%100%defectivepercentageQC7tools---Cause-and-effectdiagramWhatisCause-and-effectdiagram?Itisatooltoanalyzethequalitycharacteristics(effect)andthepotentialfactortoeffectthecharacteristics(cause).Keypoints1.PersonnelfromdifferentDept;2.Analyzethecauseasdetailaspossible;3.Eachqualitycharacteristicneedsacause-and-effectdiagram;4.Verifytheproblemcanbesolvedornot;ifnot,subdividethecause.ImplementProcedure1.3-6variousdeptrepresentativestoformagroup;2.Topic:forexample,whydoesdimensionofgearvary?3.Drawouttherib,setthemajorcauseWhydoesdimensionofgearvary?ManMachineMaterialMethodEnvironmentImplementProcedure4.Findoutthedetailcauseandaddtothediagram(“BrainStorm”isrecommended);5.Markthecausethatmaybetherootoftheproblemandtakecorrectiveaction.Whydoesdimensionofgearvary?ManMachineMethodEnvironmentMaterialWrongoperationNotenoughtrainingNotimelycheckingPatrolintervaltoolongLaxdisciplineInsufficienthardnessVarioushardnessDifferentsuppliersImpurematerialEquipmentprecisionHardtoadjustInstabl