【文章內(nèi)容簡(jiǎn)介】 lows:MeasurementError:Part: Operator:Interaction: Reproducibility:Repeatability: Measurement Error:Total:Analysis Techniques: Variable Gage Analysis1. Acceptability Criteria:2. Thegagerepeatabilityandreproducibility:%RR(P/Pratio:%totaloftotal3. variance。P/Tration:%totaloftolerance):4. Lessthan10% Outstanding 5. 10%to20% Capable 6. 20%to30% MarginallyCapable 7. Greaterthan30% NOTCAPABLE 8. FortheP/PratioandtheP/Tratio,eitherorbothapproachescanbetaken9. dependingontheintendeduseofthemeasurementsystemandthedesiresofthe10. customer.Generally,Ifthemeasurementsystemisonlygoingtobeusetoinspect11. iftheproductmeetsthespecs,thenweshouldusethe%RRbaseonthetolerance12. (P/Tratio).Ifthemeasurementsystemisgoingtobeuseforprocessoptimization13. /characterizationanalysis,thenweshouldusethe%RRbaseontotalvariation14. (P/Pratio).Analysis Techniques: Variable Gage Analysis1. Acceptability Criteria:2. ForaGagedeemedtobeINCAPABLEforit’sapplication.Theteammustreview3. thedesignofthegagetoimproveit’sintendedapplicationandit’sabilityto4. measurecriticalmeasurementscorrectly.Also,ifarecalibrationisrequired,please5. followcaliberationsteps.6. Ifrepeatabilityislargeparedtoreproducibility,thereasonsmightbe:7. 1)theinstrumentneedsmaintenance,thegageshouldberedesigned8. 2)thelocationforgagingneedstobeimproved9. 3)thereisexcessivewithinpartvariation.10. Ifreproducibilityislargeparedtorepeatability,thenthepossiblecauses11. couldbe:12. 1)inadequatetrainingonthegage,13. 2)calibrationsarenoteffective,14. 3)afixturemaybeneededtohelpusethegagemoreconsistently.Analysis Techniques: Variable Gage Analysis1. The Measurement Bias:2. Usingacertifiedsample,andacontrolchartofrepeatedmeasurements,thebiasof3. ameasurementprocesscanbedetermined.Biasisthedifferencebetweentheknown4. valueandtheaverageofrepeatedmeasurementoftheknownsample.Biasis5. sometimescalledaccuracy.Process Variation = 6 Sigma RangePercent Bias = BIASProcess VariationAnalysis Techniques: Variable Gage Analysis1. Linearity:2. Linearityofameasurementprocessisthedifferenceinthebiasorprecisionvalues3. throughtheexpectedoperatingrangeofthegauge.Toevaluatelinearity,agraph4. paringthebiasorprecisiontotheexpectedoperatingrangeiscreated.5. Aproblemwithlinearityexistsifthegraphexhibitsdifferentbiasorprecisionfor6. differentexpectedoperatingranges.7. Byusingthefollowingprocedure,linearitycanbedetermined.8. 1)Selectfivepartswhosemeasurementscovertheoperatingrangeofthegage.9. 2)Verifythetruemeasurementsofeachpart.10. 3)Haveeachpartberandomlymeasured12timesonthegagebyoneoperator.11. 4)Calculatethepartaverageandthebiasforeachpart.12. 5)Plotthebiasandthereferencevalues.13. 6)Calculatethelinearregressionlinethatbestfitsthesepoints.Analysis Techniques: Variable Gage Analysis7)Calculatethegoodnessoffitstatistic:Analysis Techniques: Variable Gage Analysis8)Determinelinearityandpercentlinearity:Linearity=SlopexProcessvariation(?m)%Linearity=100[linearity/ProcessVariation]The acceptability criteria of Bias, LinearitydependonQualityControlPlan,characteristicbeingmeasuredandgagespeciality,suggestedcriteriaofESGisasfollowing:Under5%acceptable5%to15%maybeacceptablebaseduponimportanceofapplication,costofmeasurementdevice,costofrepairs,etc.,Over15%ConsiderednotacceptableeveryeffortshouldbemadetoimprovethesystemThe stabilityisdeterminedthroughtheuseofacontrolchart.Itisimportanttonotethat,whenusingcontrolcharts,onemustnotonlywatchforpointsthatfalloutsideofthecontrollimits,butalsocareotherspecialcausesignalssuchastrendsandcenterlineforthedetectionofsuchsignalscanbefoundinmanypublicationsonSPC.Analysis Techniques: Attribute Gage Study?Short Method:AShortMethodexampleforbatterylengthgo/nogogagestudy:TheShortmethodneedtobeconductbyselecting20partswhichhavebeenmeasuredbyavariablegageinadvance,someofthe parts are slightly below and above both specification limits.Twoappraisersthenmeasureallpartstwicerandomly.Measurement Result table 1Analysis Techniques: Attribute Gage StudyAcceptabilitycriteria:Ifallmeasurementresults(fourperpart)agree,thegageisacceptable.Ifthemeasurementresultsdonotagree,thegagecannotbeaccepted,itmustbeimprovedandreevaluated.Conclusion:Becausetable1listedmeasurementresultsarenotwholeagreement,atpart15and17,appraiser’sdecisionsarenotagree.sothebatterylengthgagecannotbeusedandmustbeimprovedandreevaluated.Analysis Techniques: Attribute Gage Study?Hypothesis Test Analysis:Shortmethodshouldknowthevariablereferencevalueofsamplesinadvance.However,insomesituationsitishardtorealizetogetallsamplesvariablerefer