ASME B89.7.6 pdf download Guidelines for the Evaluation of Uncertainty of Test Values Associated With the Verification of Dimensional Measuring Instruments to Their Performance Specifications
This Standard provides guidelines for evaluating the uncertainty of test values obtained when verifying dimensionalmeasuring instruments’to an ASME B89 testing protocol. The scope is limited to the case in which the test measurand isthe error of indication at a rated operating condition; hence, test measurands such as the “worst possible” error otindication that might occur at any operating condition (including those conditions that are not tested) are outsidethe scope of this Standard.
ASME B89 testing protocols are composed of many individual tests, each test yielding one test value that is an estimateof the instrument’s measurement error at the particular operating condition tested, and this test value is comparedapainstthe maximum permissible error (MPE) (specified forthat rated operating condition) using the protocol’s decisionrule. Although the MPE is specified by the instrument manufacturer for all rated operating conditions, the test valueuncertainty is associated only with the test value obtained at the particular operating condition prevailing at the momentthe test value was obtained (unless a correction to the indication is performed that is allowed by the test protocolBecause each test investigates the error of indication at a particular rated operating condition, the test value uncer-tainty does not include the robustness or comprehensiveness ofthe testing protocol,.e. it does not address the numberoftests or their distribution over different rated operating conditions. This issue is addressed by the standardizationcommittee creating the testing protocol; the committee balances the number of tests against the amount of timeand effort to complete the testing protocol.
The scope of this Standard excludes issues associated with the evaluation of the uncertainty of future measurementresults on workpieces and focuses solely on the test value uncertainties used to verify the instrument’s performancespecification.Typically, the test value uncertainty is much smaller than the associated MPE value of the verification test
The following definitions are specific to this Standard:instrument: the measuring system that is under verification to its performance specificationNOTE: In this Standard, the term “instrument” is equivalent to “instrument under verification.
verifcation system: the measuring system that is used to verify an instrument to its performance specification.NOTE: In this Standard, the verification system includes everything necessary to execute the testing protocol. This includes thecalibrated reference quantity, equipment used in the transfer process, the human operator (if one is involved), computationsand any other analysis needed, environmental and other conditions required by the instrument under verilfication, and aniinput quantities required to realize the measurand of the verification test.
The following is a list of publications referenced in this Standard:
ASME B89.114-2018 Calipers
ASME B89.4.10360.2-2008, Acceptance Test and Reverification Test for Coordinate Measuring Machines (CMMs)-Part 2: CMMs Used for Measuring Linear Dimensions (Technical Report)