什么是Measurement System Capability Variable Data

MEASUREMENTSYSTEMSCAPABILITYVARIABLEDATA



Objective: Toevaluatetheamountofvariationthemeasurementsystemcontributestotheoverallprocess.



Terminology

ObservedValue:Themastervalueofthepartsyouareinspectingandanymeasurementerror.

ObservedVariability:Thevariabilityinthepartsyouaremeasuringandanymeasurementvariability.

GaugeRepeatability:Thevariationinthemeasurementsobtainedwhenoneoperatorusesthesamegaugeformeasuringtheidenticalcharacteristicsofthesameparts.

GaugeReproducibility:Thevariationintheaverageofmeasurementsmadebydifferentoperatorsusingthesamegaugewhenmeasuringidenticalcharacteristicsofthesameparts.





GaugeR&RMethod:



Randomlyselectsamplesrepresentingatleast80%oftotalprocessrange.



CalibratetheGauge,orensurethatithasbeencalibrated.



SetuptheMinitabWorksheetfortheGageR&Rstudy.

-ColumnHeadingforOperator,Trial,Part

-Use>Calc>MakePatternedData>SimpleSetofNumbers(foreachinput)



4)Havethefirstoperatormeasureallthesamplesonceinrandomorder.

(Blindsampling,inwhichtheoperatordoesnotknowtheidentityofthepart,shouldbeusedtoreducehumanbias.Partsmustrepresent80%ofalllong-termvariability.)



Havethesecondoperatormeasureallthesamplesonceinrandomorder;Continue

untilalloperatorshavemeasuredthesamplesonce(thisisTrial1)



Repeatsteps4-5fortherequirednumberoftrials.



7)EnterthedataandtoleranceinformationintoMinitab.

Stat>QualityTools>GageR&RStudy

Stat>QualityTools>GageRunChart



Analyzetheresultsbyassessingthequalityofthemeasurementsystembasedon

theguidelinesonthefollowingpage.Determinefollow-upactions.













GageR&RStudy-Two-WayANOVATableWithInteraction



ThisexampleisfromtheMinitabfileGAGERR.MTWandshowsboththesessionwindowandthegraphicaloutput.Goto”DataFiles"ontheTools/Metricspageofthiswebsiteandgetfile"booklet.mtw"totryit.





SourceDFSSMSFP



RRPart92.058710.22874539.71780.00000

Operator20.048000.0240004.16720.03256

OperatorRRPart180.103670.0057594.45880.00016

Repeatability300.038750.001292

Total592.24912



SourceVarCompStdDev5.15Sigma



TotalGageR&R0.0044370.0666150.34306

Repeatability0.0012920.0359400.18509

Reproducibility0.0031460.0560880.28885

Operator0.0009120.0302000.15553

OperatorRRPart0.0022340.0472630.24340

Part-To-Part0.0371640.1927810.99282

TotalVariation0.0416020.2039651.05042



Source%Contribution%StudyVar



TotalGageR&R10.6732.66

Repeatability3.1017.62

Reproducibility7.5627.50

Operator2.1914.81

OperatorRRPart5.3723.17

Part-To-Part89.3394.52

TotalVariation100.00100.00





TheanalysisshowsthatthetotalgaugeR&Ris10.67%.Youmayrecallfromyoursixsigmatrainingthatanexcellentmeasurementsystemwillgivea%contributionof<1%andaborderlinesystemwillgivea%contributionof1%to9%.Soourexampleismarginallyoutsidethisguideline.Whatshouldwedo?



TheTotalgaugeR&RissplitintoRepeatability,3.1%,andReproducibility,7.56%,becauseReproducibilityisthelargesterrorthisshouldbeinvestigated.Remember,Reproducibilityisthedifferencebetweenoperatorssoweshouldinvestigatethetrainingaspectsofhowtheoperatorsusethegauge.Thisdoesnotmeanwestarttoblametheoperatorortheinspectorbutweconcentrateontheprocess.



Minitabalsoproducesafullgraphicaloutput,whichisshownbelowforourexample.Foranexplanationofthesegraphsreviewtheminitabhelpmenuforthefollowingfiles:

GAGEAIAG.MTWandGAGE2.MTW.AlsoanexcellentreferenceforMeasurementsystemanalysisistheAIAGmanual"MSEA."PleaseseeaMasterBlackBeltforfurtheradvice.





































Nodon’tpanicwe’lljustconcentrateon%contribution



Doyouexpectmetounderstandallofthisrubbish?