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QuickGuidetoPrecisionMeasuringInstrumentsDepthGagePerformanceEvaluationMethodJISB7518wasrevisedandissuedin2018astheJapaneseIndustrialStandardsofthedepthgage,andthe“Instrumentalerror”indicatingtheindicationerrorofthedepthgagehasbeenchangedto“Maximumpermissibleerror(MPE)ofindication”.The“Instrumentalerror”oftheconventionalJISadoptsacceptancecriteriathatthespecicationrange(precisionspecication)equalsacceptancerange,andtheOK/NGjudgmentdoesnotincludemeasurementuncertainty(Fig.1).The“Maximumpermissibleerror(MPE)ofindication”ofthenewJISemploysthebasicconceptoftheOK/NGjudgmenttakingintoaccounttheuncertaintyadoptedintheISOstandard(ISO14253-1).Thevericationofconformityandnonconformitytothespecicationsisclearlystipulatedtousetheinternationallyrecognizedacceptancecriteria(simpleacceptance)whenthespecicationrangeequalstheacceptancerange,anditisacceptedthatthespecicationrangeequalstheacceptancerangeifagivenconditionconsideringuncertaintyismet.TheabovesaidinternationallyrecognizedacceptancecriterionisISO/TR14253-6:2012(Fig.2).ThefollowingdescribesthestandardinspectionmethodincludingtherevisedcontentofJIS2018.Fig.1ConventionalJISInstrumentalerrorJISB7518-1993SpecificationrangeNon-conformityrangeConformityrangeNon-conformityrangeDepthGagesMaximumpermissibleerrorofpartialmeasuringfacecontactEMPE[JISB7518:2018]TheMaximumpermissibleerrorEMPEofadepthgageisanindicationerrorappliedtodepthmeasurement.Table1showstheMaximumpermissibleerrorEMPEoftheindicationvalueofthepartialmeasuringsurfacecontacterror.EMPEforanydesiredheightisobtainedbymeasuringtheheightoftwoequallengthgaugeblocks,orequivalent,withaheightgageonaprecisionsurfaceplate(Fig.3)andthensubtractingthegaugeblocksizefromthemeasuredsize.Table1:MaximumpermissibleerrorEMPEofpartialmeasuringfacecontactofaconventionaldepthgageMeasurementdepth50orlessOver50,100orlessOver100,200orlessOver200,300orlessOver300,400orlessOver400,500orlessOver500,600orlessScaleinterval,graduationorresolutionUnit:mm0.05±0.05±0.06±0.07±0.08±0.09±0.10±0.110.02or0.01±0.02±0.03±0.04±0.05Note:EMPEincludesthemeasurementerrorarisingfromstraightness,flatnessofthemeasuringsurfaceandparallelismwiththereferencesurface.Fig.3:DeterminationofpartialmeasuringfacecontacterrorAcceptancerangeDepthgageUncertaintyisnotincludedinjudgmentSpecificationrange=AcceptancerangeGaugeblockHeightgageFig.2NewJISMaximumpermissibleerror(MPE)JISB7518:2018(ISO/TR14253-6:2012)Non-conformityrange(Rejected)UUSpecificationrangeConformityrangeAcceptanceNon-conformityrange(Rejected)PrecisionsurfaceplateUUUncertaintyrangeUncertaintyrangeWhenaconditionconsideringuncertaintyissatisfiedSpecificationrange=ConformityrangeGaugeblockPrecisionsurfaceplateThe“Instrumentalerror”indicatingtheindicationerrorofJIShasbeenchangedto“Maximumpermissibleerror(MPE)ofindication”forthefollowingmodels:•SERIES571ABSOLUTEDigimaticDepthGagedescribedonpageD-69toD-70(Allmodels)•SERIES527VernierDepthGagedescribedonpageD-71(Allmodels)•SERIES527,571HookEndTypedescribedonpageD-72toD-74(Allmodels)•SERIES571MiniDepthGagedescribedonpageD-75(Allmodels)D-80
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