ASME_B89.7.2-1999.pdf

STD.ASME B89.7.2-ENGL 19990759b7006159b0538ASME B897.2-1999DIMENSIONALMEASUREMENTAN AMERICAN NATIONAL STANDARDThe American Society ofMechanical EngineersNot for ResaleSTD.ASME B89.7.2-ENGL199907596700b15962300Date of Issuance:March 1,2000This Standard will be revised when the Society approves the issuance of anew edition.There will be no addenda issued to this edition.ASME will issue written replies to inquiries concerning interpretation oftechnical aspects of this Standard.The interpretations are not part of theStandard.ASME is the registered trademark of The American Society of Mechanical Engineers.This code or standard was developed under procedures accredited as meeting the criteria forAmerican National Standards.The Standards Committee that approved the code or standardwas balanced to assure that individuals from competent and concerned interests have had anopportunity to participate.The proposed code or standard was made available for public reviewand comment that provides an opportunity for additional public input from industry,academia,regulatory agencies,and the public-at-large.ASME does not approve,rate,or endorseany item,construction,proprietary device,or activity.ASME does not take any position with respect to the validity of any patent rights asserted inconnection with any items mentioned in this document,and does not undertake to insure anyoneutilizing a standard against liability for infringement of any applicable Letters Patent,nor assumesany such liability.Users of a code or standard are expressly advised that determination of thevalidity of any such patent rights,and the risk of infringement of such rights,is entirely theirown responsibility.Participation by federal agency representative(s)or person(s)affiliated with industry is not tobe interpreted as government or industry endorsement of this code or standard.ASME accepts responsibility for only those interpretations of this document issued inaccordance with the established ASME procedures and policies,which precludes the issuanceof interpretations by individuals.No part of this document may be reproduced in any form,in an electronic retrieval system or otherwise,without the prior written permission of the publisher.The American Society of Mechanical EngineersThree Park Avenue,New York,NY 10016-5990Copyright2000 byTHE AMERICAN SOCIETY OF MECHANICAL ENGINEERSAll Rights ReservedPrinted in U.S.A.Copyright ASME InteratonalNot for ResaleSTD.ASME B89.7.2-ENGL19990759b70061596413B3uncertainty:ISO-14253-1 Decision Rules for Proving Conformance or Non-Conformancewith Specifications and ISO TR 14253-2 Guide to the Estimation of Uncertainty in GPSMeasurement,in Calibration of Measuring Equipment and in Product Verification.TheASME B89.7.2 Standard makes use of the methods of the foregoing documents to determineuncertainty.In considering its assignment,the B89.7.2 Working Group determined that a singlecookbookstandard covering all valid methods for measuring all possible workpiecefeatures for all possible purposes under all possible conditions is impractical.Some of theproblems are the difficulty of writing and maintaining such an extensive document,lackof documentation for some types of measurements,and rapidly-changing technology.The approach of the ASME B89.7.2 Standard is to identify the principles applicable toall dimensional measurements,and to reference detailed standards for specific classes ofmeasurements as they become available.Two strategies are used.The first is to ensure thevalidity of dimensional measurements by specifying requirements for preparation,approval,and use of dimensional measurement plans.The second is to provide appendices whichdiscuss methods and resources for developing such plans.The ASME B89.7.2 Standard considers that a measurement method is acceptable if itresults in an acceptable measurement uncertainty.Thus,for example,a gage producing alimited point data set(e.g.a coordinate measuring machine)may be used to determinecompliance with Y14.5 if the uncertainty component due to limited measurement can bereasonably estimated and if total uncertainty is acceptable.Acceptability may be definedby an appropriate balance between measurement quality and cost.For example,if amanufacturing process produces few bad parts,a low-quality measurement method may beadequate.For parts where an out-of-tolerance condition could cause serious injury and costof rejecting a good part is high,the quality requirement might be stringent and the acceptableuncertainty small.These considerations may be embodied in contracts or company policies.The body of this Standard delineates requirements and recommendations for dimensionalmeasurement planning.Actions required for compliance with the Standard are identified byuse of the word shall.Compliance with other identified actions is strongly recommendedto ensure quality in measurement.The appendices provide examples of how to develop aplan,how to select gaging.and how to estimate uncertainty contributions.Means arepresented for determining the probabilities of mistakes in part acceptance.These probabilitiesare useful in evaluating plan acceptability.A bibliography is included.This Standard providesthe user with means for meeting the requirements of ANSI/ASQC E2 Guide to InspectionPlanning.While some of the approaches of this Standard are departures from past methods,theyare consistent with current state of the art,and with other standards under developmentincluding the work of ISO TC 213 Working Group 4.Another related effort is AP 219(Application Protocol 219-Exchange of Dimensional Inspection Information)which is partof ISO TC 184/SC4(STEP).It is anticipated that future work of the B89.7.2 Working Group will be in the area ofupdating this first edition of the Standard in response to further study,public comment,and other standards developments.This Standard was approved by the American National Standards Institute on October26.1999.ivwh ASMENo 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