D-39DMaximum permissible error of partial measuring surface contact error EMPE [JIS B 7507: 2016]The partial measuring surface contact error of a caliper is an indication error applied to outside measurement.Table 1 shows the Maximum permissible error EMPE for various measuring ranges and graduation/resolution of a caliper.The value can be obtained by inserting a gauge block (or an equivalent standard) between the outside measuring surfaces (Fig. 3), measuring it at arbitrary positions between the jaws and then subtracting the dimension of the gage from the maximum or minimum indicated value.Scale Shift Error SMPE [JIS B 7507: 2016]The scale shift error in a caliper is an indication error of the inside measurement, depth measurement, etc., if measuring surfaces other than the outside measuring surfaces are used.The Maximum permissible error SMPE of the indication value for inside measurement is given in Table 1. The Maximum permissible error SMPE of depth measurement is obtained by adding 0.02 mm to a value in Table 1.The indication error for inside measurement can be obtained by using gauge blocks (or equivalent standards) and standard jaws from an accessory set to form accurate inside dimensions for calibration (Fig. 4), with the error being given by the indicated value minus the gauge block size.Performance evaluation method for the caliperJIS B 7507 was revised and issued in 2016 as the Japanese Industrial Standards of the caliper, and the “Instrumental error” indicating the indication error of the caliper has been changed to “Maximum permissible error (MPE) of indication”.The “Instrumental error” of the conventional JIS adopts acceptance criteria that the specication range (precision specication) equals acceptance range, and the OK/NG judgment does not include measurement uncertainty. (Fig. 1)The “Maximum permissible error (MPE) of indication” of the new JIS adopts the basic concept of the OK/NG judgment taking into account the uncertainty adopted in the ISO standard (ISO 14253-1).The verication of conformity and nonconformity to the specications is clearly stipulated to use the internationally recognized acceptance criteria (simple acceptance) when the specication range equals the acceptance range, and it is accepted that the specication range equals the acceptance range if a given condition considering uncertainty is met.In this case, the internationally recognized acceptance criterion is ISO/TR 14253-6: 2012. (Fig. 2)The following describes the standard inspection method including the revised content of JIS 2016.Fig. 1Fig. 2Conventional JIS Instrumental errorJIS B 7507-1993 Conformity rangeUncertainty is not included in judgmentSpecication range＝Acceptance rangeSpecication rangeAcceptance rangeNon-conformity rangeNon-conformity rangeNew JIS Maximum permissible error (MPE)JIS B 7507: 2016 (ISO/TR 14253-6: 2012)When a condition considering uncertainty is satisedSpecication range＝Conformity rangeNon-conformity rangeNon-conformity rangeConformity rangeSpecication rangeUncertaintyrangeUncertaintyrangeU(Rejected)(Rejected)AcceptanceUUUTable 1: Maximum permissible error EMPE of partial measuring surface contact error in a conventional caliperUnit: mmMeasurement rangeScale interval, graduation or resolution0.050.0250 or less±0.05±0.02Over 50, 100 or less±0.06±0.03Over 100, 200 or less±0.07Over 200, 300 or less±0.08±0.04Note: EMPE includes the measurement error arising from the straightness, flatness and parallelism of the measuring surfaces.Gauge blockGauge blockFig. 3: Determining partial measuring surface contact errorFig. 4: Determining scale shift errorThe “Instrumental error” indicating the indication error of JIS has been changed to “Maximum permissible error (MPE) of indication” for the following three models:• Vernier Caliper SERIES 530 — Standard model described on page D-9 (530-101 530-108 530-109)• Vernier Caliper SERIES 532 — with fine adjustment described on page D-11 (All models)• Vernier Caliper SERIES 531 — with thumb grip described on page D-11 (All models)
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