ASME B89.1.14-2018
Calipers
A N A M E R I C A N N A T I O N A L S T A N D A R D
ASME B89.1.14-2018
Calipers
AN AMERICAN NATIONAL STANDARD
Date of Issuance: May 31, 2018
This Standard will be revised when the Society approves the issuance of a new edition. ASME issues written replies to inquiries concerning interpretations of technical aspects of this Standard. Interpretations are publishe published d on theCommittee theCommittee webpage andunder http://g http://go.asm o.asme.or e.org/In g/Interp terpsDat sDatabase abase.. Periodica Periodically lly certain certain actions actions of the ASME B89Committ B89Committee ee maybe publi publishe shed d as Cases.Casesare Cases.Casesare publi publish shed ed on the the ASME ASME websit website e unde underr theB89 Commit Committe tee e Page Page at http:/ http:/// go.asme.org/B89committee as they are issued. Errata to codes and standards may be posted on the ASME website under the Committee Pages to provide corrections to incorr incorrect ectly ly publi publish shed ed items,or items,or to correc correctt typogr typograph aphica icall or gramma grammatic tical al errorsin errorsin codes codes andstandard andstandards. s. Such Such errata errata shall shall be used used on the date posted. The B89 Committee Page can be found at http://go.asme.org/B89committee. There is an option available to automatically receive an e-mail notification when errata are posted to a particular code or standard. This option can be found on the appropriate Committee Page after selecting “Errata” in the “ Publication Information ” section.
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CONTENTS Foreword
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Committee Roster
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Correspondence With the B89 Committee
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1
Scope
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Definitions
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References
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Caliper Design
5
Maximum Permissible Errors
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iv v vi 1 1 1 1 1
Nonmandatory Nonmandatory Appendices Appendices A
Good Operating Procedures
B
Environ ronmental Considerat rations
C
Measurement Uncertainty
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7 9 10
Figures 5.10.4-1 5.10.4-1
Testing Testing Partial Partial Surface Surface Contact Contact Error Error — Example Example Test Points Points on on Two Calipe Calipers rs Showing Showing Differe Different nt Lengths and Different Distances From the Beam
5
5.10.6 5.10.6-1 -1
Testin Testing g Line Line Contac Contactt Error Error
5
5.10.7 5.10.7-1 -1
Testin Testing g Scale Scale Shift Shift Erro Errorr — Insid Inside e Measu Measurem rement ent
5.10.7 5.10.7-2 -2
Testin Testing g Scale Scale Shift Shift Erro Errorr — Depth Depth Measur Measureme ement nt
5.10.7 5.10.7-3 -3
Testin Testing g Scale Scale Shift Shift E Erro rrorr — Step Step Measur Measureme ement nt
5.10.8-1 5.10.8-1
Effect Effect of Crossed Crossed Knife-Ed Knife-Edge ge Internal Internal Measuring Measuring Faces
5.10.8-2 5.10.8-2
Testing Testing Scale Scale Shift Shift Error — Interna Internall Measurem Measurement ent With Crossed Crossed Knife Knife-Edg -Edge e
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6 6 6 6 6
Tables 5.8-1 5.8-1
Maximu Maximum m Permis Permissib sible le Errors Errors of Calipe Calipers rs With With Measur Measuring ing Range Range Up to 1 000 mm (40 in.) in.)
5.10.4 5.10.4-1 -1
Number Number of Test Test Points Points for E for E MPE MPE
C-4.1-1 C-4.1-1
Uncertaint Uncertainty y Budget Budget for Perfor Performance mance Verificati Verification on of of the Partial Partial Surface Surface Conta Contact ct Error Error for for a 0-mm to 150-mm Digital Caliper
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4 12
FOREWORD ASME B89 Standards Committee on Dimensional Metrology, under procedures approved by the American National Standards Institute, has the responsibility of preparing standards that encompass the inspection and the means of measuringcharacter measuringcharacteristic isticss of various various geometricalparamet geometricalparameters ers suchas diameter,length, diameter,length, flatness,paralleli flatness,parallelism,concentri sm,concentricity, city, taper, taper, andsquarene andsquareness.Since ss.Since calipe calipers rs arewidely arewidely used used forthe measur measureme ement nt andcomparis andcomparison on of some some of these these featur features,the es,the B89 Consensu Consensuss Committee Committee authorized authorized formation formation of Project Project Team B89.1.14 to prepare prepare this Standard. Standard. The Internati International onal Organizati Organization on for Standardiz Standardization ation (ISO) also develops develops standards standards in dimensio dimensional nal metrology. metrology. ISO standardsareappli dardsareapplicab cablein lein theUnitedState theUnitedStatess butmaynot addres addresss allthe needsof needsof Americ Americanindu anindustr stry,such y,such asthe useof both both the U.S. Customary and SI systems. This Standard has been developed to be consistent with ISO 13385-1:2011, which addre address sses es the desig design n and metrol metrologi ogical cal charac character terist istics ics of calipe calipers. rs. This This Standa Standard rd has also also been been develo develope ped d to comple complemen ment t ISO 13385-1:2011by 13385-1:2011by providingaddition providingadditional al informati information on useful useful in the specificat specification,verificat ion,verification,and ion,and calibratio calibration n of calipers. calipers. This Standard is not intended to contradict ISO 13385-1:2011 but does include additional technical information and requirements that exceed ISO 13385-1:2011. This Standard adopted some material from the obsolete Federal Specification GGG-C-111C, published by General Services Administration (GSA), as well as manufacturer’s current practices and technologies. In addition, this Standard includes many of the uncertainty and traceability concepts developed and standardized by the ASME B89.7 Subcommittee. This Standard was approved by the American National Standards Institute on February 27, 2018.
iv
ASME B89 COMMITTEE Dimensional Metrology (The following is the roster of the committee at the time of approval of this Standard.)
STANDARDS COMMITTEE OFFICERS T. C. Charlton, Jr., Chair S. D. Phillips, Vice Chair R. Richmond, Secretary
STANDARDS COMMITTEE PERSONNEL T. C. Charlton, Jr., Charlton Associates B. Crowe, CDI Engineering Solutions J. D. Drescher, UTC — Pratt & Whitney M. L. Fink, The Boeing Co. G. A. Hetlan Hetland, d, Internatio International nal Institute Institute of Geometric Geometric Dimensioningand Dimensioningand Tolerancing M. Liebers, Professional Instruments Co. R. L. Long, ANSI-ASQ National Accreditation Board E. Morse, UNC Charlotte B. Parry, Consultant P. Pereira, Caterpillar, Inc. S. D. Phillips, National Institute of Standards and Technology B. S. Pippenger, Rolls-Royce R. Richmond, The American Society of Mechanical Engineers
J. G. Salsbury, Mitutoyo America Corp. D. Sawyer, National Institute of Standards and Technology J. R. Schmidt, Optical Gaging Products, Inc. C. Shakarji, National Institute of Standards and Technology R. L. Thompson, U.S. Air Force E. R. Yaris, Lowell, Inc. K. L. Skinner, Alternate, Alternate, Air Force Metrology and Calibration Caterpillar,, Inc. D. E. Beutel, Honorary Member , Caterpillar T. E. Carpenter, Honorary Member , U.S. Air Force D. J. Christy, Honorary Member , Mahr Federal, Inc. R. J. Hocken, Honorary Member , Center for Precision Metrology M. P. Krystek, Honorary Member , Physikalisch-Technische Bundesanstalt B. R. Taylor, Honorary Member , Renishaw PLC
SUBCOMMITTEE 1 — LENGTH J. G. Salsbury, Chair , Mitutoyo America Corp. D. Sawyer, Sawyer, ViceChair , National National Instituteof Instituteof Standardsand Standardsand Technology Technology D. J. Carlson, The Carlson, The L. S. Starrett Co. B. Crowe, CDI Engineering Solutions D. Everett, National Institute of Standards and Technology M. L. Fink, The Boeing Co. D. T. Harris, Glastonbury Southern Gage K. Kokal, Micro Kokal, Micro Laboratories, Inc. A. Kumar, Kumar, Mitutoyo America Corp. W. D. Lehmus, Consultant
R. L. Long, ANSI-ASQ National Accreditation Board E. Morse, UNC Charlotte B. Parry, Consultant P. Pereira, Caterpillar, Inc. C. Shakarji, National Institute of Standards and Technology K. L. Skinner, Air Force Metrology and Calibration E. S. Stanfield, National Institute of Standards and Technology R. L. Thompson, U.S. Air Force B. T. Miller, Alternate, Alternate, The Boeing Co.
WORKING GROUP B89.1.14 — CALIPERS K. L. Skinner, Chair, Chair, Air Force Metrology and Calibration B. Crowe, CDI Engineering Solutions J. C. Davies, Davies, Honeywell Federal Manufacturing and Technologies A. Kumar, Kumar, Mitutoyo America Corp. W. C. Lehmus, Consultant R. L. Long, ANSI-ASQ National Accreditation Board
B. Parry, Consultant J. G. Salsbury, Mitutoyo America Corp. D. Sawyer, National Institute of Standards and Technology C. Shakarji, National Institute of Standards and Technology H. Tran, Tran, Sandia National Laboratories
v
CORRESPONDENCE WITH THE B89 COMMITTEE maintained with the intent to represent the consensus of concerned General. ASME Standards are developed and maintained interests. As such, users of this Standard may interact with the Committee by requesting interpretations, proposing revisions or a case, and attending Committee meetings. Correspondence should be addressed to: Secretary, B89 Standards Committee The American Society of Mechanical Engineers Two Park Avenue New York, NY 10016-5990 http://go.asme.org/Inquiry Revisions ons are made made period periodica ically lly to the Stand Standard ard to incorp incorpora orate te change changess that that appear appear necess necessary ary Proposing Revisions. Revisi or desira desirable ble,, as demons demonstra trated ted by the experi experienc ence e gained gained from from the appli applicat cation ion of the Standa Standard. rd. Approv Approved ed revisi revisions ons will will be published periodically. The Committee welcomes proposals for revisions to this Standard. Such proposals should be as specific as possible, citing the paragraph number(s), the proposed wording, and a detailed description of the reasons for the proposal, including any pertinent documentation. Cases may be issued issued to provid provide e altern alternati ative ve rules rules when when justif justified ied,, to permit permit early early implem implement entati ation on of Proposing Proposing a Case. Cases an approv approved ed revisi revision on when when the need need is urgent urgent,, or to provid provide e rules rules not covere covered d by existi existing ng provis provision ions. s. Cases Cases are effect effective ive immediately upon ASME approval and shall be posted on the ASME Committee web page. Requests for Cases shall provide a Statement of Need and Background Information. The request should identify the Standard and the paragraph, figure, or table number(s), and be written as a Question and Reply in the same format as existing Cases. Requests for Cases should also indicate the applicable edition(s) of the Standard to which the proposed Case applies. request, t, the B89 Standa Standards rds Commit Committee tee will will render render an interp interpret retati ation on of any requir requireme ement nt of the Interpretations. Upon reques Standa Standard.Inte rd.Interpr rpreta etatio tions ns canonlybe render renderedin edin respon responseto seto a writte written n reques requestt sent sent to theSecretar theSecretary y ofthe B89Standard B89Standardss Committee. Requests for interpretation should preferably be submitted through the online Interpretation Submittal Form. The form form is access accessibl ible e at http:/ http://go /go.as .asme. me.org org/In /Inter terpre pretat tation ionReq Reques uest. t. Upon Upon submit submittal tal of the form, form, the Inquir Inquirer er will will receiv receive e an automatic e-mail confirming receipt. If the Inquirer is unable to use the online form, he/she may mail the request to the Secretary of the B89 Standards Committee at the above address. The request for an interpretation should be clear and unambiguous. It is further recommended that the Inquirer submit his/her request in the following format: Subj Subjec ect: t:
Cite Cite the the appl applic icab able le para paragr grap aph h numb number er(s (s)) and and the the topi topicc of the the inqu inquir iry y in one one or two two word words. s.
Edit Editio ion: n:
Cite Cite the the appl applic icab able le edit editio ion n of the the Stan Standa dard rd for for whic which h the the inte interp rpre reta tati tion on is bein being g requ reques este ted. d.
Ques Questi tion on::
Phra Phrase se the the ques questi tion on as a requ reques estt for for an inte interp rpre reta tati tion on of a spec specif ific ic requ requir irem emen entt suit suitab able le for for genera generall unders understan tandin ding g and use, use, not as a reques requestt for an approv approval al of a propri proprieta etary ry design design or situat situation ion.. Pleaseprovi Pleaseprovide de a conden condensedand sedand precis precise e questi question,compo on,composedin sedin such such a waythat a “yes” or “no” reply is acceptable.
Proposed Proposed Reply(i Reply(ies): es):
Provide Provide a proposed proposed reply(ies) reply(ies) in the the form form of “Yes” “Yes” or “No,” with with explanat explanation ion as neede needed. d. If entering replies to more than one question, please number the questions and replies.
Background Information: Provide the Committee with with any background information information that will assist the Committee Committee in understanding the inquiry. The Inquirer may also include any plans or drawings that are necess necessary ary to explai explain n the questi question;howev on;however, er, they they should should not contai contain n propri proprieta etary ry names names or information.
vi
Reques Requests ts that that arenot in theformat theformat descri describedabov bedabove e maybe rewrit rewrittenin tenin theappropri theappropriateform ateformat at by theCommitte theCommittee e prior prior to being answered, which may inadvertently change the intent of the original request. Moreover, ASME does not act as a consultant for specific engineering problems or for the general application or understanding of the Standard requirements. If, based on the inquiry information submitted, it is the opinion of the Committee that the Inquirer should seek assistance, the inquiry will be returned with the recommendation that such assistance be obtained. ASME proceduresprovide proceduresprovide for reconside reconsideratio ration n of any interpreta interpretation tion when or if additiona additionall informatio information n that might affect affect an interpretation is available. Further, persons aggrieved by an interpretation may appeal to the cognizant ASME Committee Committee or Subcommitt Subcommittee. ee. ASME does not “approve, “approve,” “certify, “certify,” “rate, “rate,” or “endorse” “endorse” any item, constructio construction, n, proprietar proprietary y device, or activity. meetings and/or telephone conferconferAttending Committee Meetings. The B89 Standards Committee regularly holds meetings ences ences that that areopen to thepublic. thepublic. Person Personss wishin wishing g to attendany attendany meetin meeting g and/ortelep and/ortelephon hone e confer conferenc ence e shouldconta shouldcontact ct the Secretary Secretary of the B89 StandardsCommitte StandardsCommittee. e. FutureCommittee FutureCommittee meeting meeting dates dates andlocationscan be found found on the Committee Committee Page at http://go.asme.org/B89committee.
vii
INTENTIONALLY LEFT BLANK
viii
ASME B89.1.14-2018
CALIPERS 1 SCOPE
Publisher: Publisher: Internati International onal Organizati Organization on for Standardiz Standardization ation (ISO), (ISO), Central Central Secretariat Secretariat,, Chemin Chemin de Blandonn Blandonnet et 8, Case Postale 401, 1214 Vernier, Geneva, Switzerland (www.iso.org)
This Standard provides the essential requirements for the specification, verification, and calibration of calipers, including vernier, dial, electronic digital, and specialty calipers. ISO 13385-1 provides for the international definition of the design and metrological characteristics of calipers important in the specification, manufacture, and purchase of calipers; however, ISO 13385-1 does not provide specification values, detailed test methods, or sufficient discussion of traceability and measurement uncertaintytoensureconsistentpracticeinthecalibration of calipers. This Standard is intended to complement, not contradict,ISO contradict,ISO 13385-1. 13385-1. For the verificati verification on or calibratio calibration n of calipers, this Standard provides sufficient detail such that the user does not require access to ISO 13385-1.
JCGM100:2008, Evaluationof Evaluationof measureme measurement nt data— Guide Guide to the expressio expression n of uncertaint uncertainty y in measureme measurement nt (GUM) JCGM JCGM 200:20 200:2008, 08, Intern Internati ationa onall vocabu vocabular lary y of metrol metrology ogy — Basic and general concepts and associated terms (VIM, third edition) Publisher: Joint Committee for Guides in Metrology, Bureau International des Poids et Mesures (BIPM), Pavillon de Breteuil, F-92312 Sèvres Cedex, France (www.bipm.org)
4 CALIPER CALIPER DESIGN DESIGN 2 DEFINITIO DEFINITIONS NS
4.1 General
The definitio definitions ns in ASMEB89.7.1, ISO13385-1:2011, ISO13385-1:2011, and JCGM 200 apply in the use of this Standard.
As defined defined in ISO 13385-1, 13385-1, calipers calipers shallincorporate shallincorporate the use of a movable slider with a measuring jaw that moves along a frame or beam with a stationary jaw to provide outside, inside, and when designed, step and/or depth measurements. The general design and workmanship of calipers shall be such to ensure compliance with the requirements of this Standard and ISO 13385-1 across the measur measuring ing range range of the calipe caliperr and in any orient orientati ation, on, unless otherwise specified by the manufacturer.
3 REFERENCES REFERENCES ASME B89.6.2-197 B89.6.2-1973 3 (R2003), (R2003), Temperature Temperature and Humidity Humidity Environment for Dimensional Measurement ASME B89.7.1-2016, Guidelines for Addressing Measurement Uncertainty in the Development and Applic Applicati ation on of ASME ASME B89 Stand Standard ardss (Techn (Technica icall Report Report)) ASME B89.7.3.1-2001, Guidelines for Decision Rules: C o n s i de d e r i n g M e a s u r em e m e n t U n c e r t a in in t y i n Determining Conformance to Specifications ASME B89.7.3.2-2007, Guidelines for the Evaluation of Dimensional Measurement Uncertainty ASME B89.7.5-2006, Metrological Traceability of Dimensional Measurements to the SI Unit of Length Publis Publisher her:: The Americ American an Societ Society y of Mechan Mechanica icall Engine Engineers ers (ASME), Two Park Avenue, New York, NY 10016-5990 (www.asme.org)
4.2 Least Count (a) Vernier calipers using SI units shall provide readings to a least count of 0.05 mm or 0.02 mm. Dial calipers using using SI unitsshallprovi unitsshallprovidereadi dereadingsto ngsto a leastcountof leastcountof 0.05 0.05 mm,0.02 mm,or 0.01 0.01 mm.Electron mm.Electronic ic digita digitall calipe calipers rs using using SI unit unitss shal shalll prov provid ide e read readin ings gs to a leas leastt coun countt of 0.01 0.01 mm. mm. (b) Vernier or dial calipers using U.S. Customary units shall provide readings to a least count of 0.001 in. Electronic digital calipers using U.S. Customary units shall provide readings to a least count of 0.001 in. or 0.0005 in.
ISO 1:2016, Geometrical product specifications (GPS) — Standard Standard reference reference temperatur temperature e for the specifica specification tion of geometrical and dimensional properties ISO 13385-1:2011, Geometrical product specifications (GPS) — Dimensional measuring equipment — Part 1: Callipers; Design and metrological characteristics ISO 14253-5:2015, Geometrical product specifications (GPS) — Inspection by measurement of workpieces andmeasuring andmeasuring equipment— equipment— Part5: Uncertaint Uncertainty y in verification testing of indicating measuring instruments
5 MAXIMUM PERMISSIBLE PERMISSIBLE ERRORS 5.1 General General The maximum permissible errors (MPE) are specified limit values for errors that apply to all measurements permitted for use of the caliper as defined by the manufacturer and following proper operation and zero setting with with theoutside theoutside measur measuring ing faces.For faces.For genera generall guida guidanceon nceon good operating procedures involving calipers, see Nonmandatory Appendices A and B. 1
ASME B89.1.14-2018
5.2 Operator
5.7 Traceabilit Traceability y
Calipers are manually operated indicating measuring instruments and as such the measurement results are dependent on the skill of the operator. All specifications apply apply when when a reason reasonabl ably y skille skilled d operat operator or uses uses the calipe caliperr in a manner consistent with normal operation of the caliper and in accordance with the manufacturer’s recommendations.
All the length length standa standards rds,, e.g., e.g., gage gage blocks blocks,, used used in deterdeterminingthe miningthe confor conforman mance ce of a calipe caliperr to specif specifica icatio tions ns must must have metrological traceability per ASME B89.7.5.
5.8 Specifications Table 5.8-1 lists 5.8-1 lists default MPE values for calipers with a meas measur urin ing g rang range e up to 1 000 000 mm (40 (40 in.) in.).. The The MPE MPE valu values es in Table 5.8-1 apply apply when when no specif specifica icatio tions ns are otherw otherwise ise stated. The caliper manufacturer shall state the MPE values for larger calipers. The caliper manufacturer may also specify different MPE values than shown in this Standard. MPE values stated by the caliper manufacturer turer shall shall confor conform m to the terms, terms, defini definitio tions, ns, and symbol symbolss in this Standard. Table 5.8-1 includes specifications in both U.S. Customary Customary and SI units. units. Due to the analog scale interval or digital resolution of a caliper, the conversion between unit unitss is not not exac exact. t. Test Test value valuess and and MPE MPE valu values es shal shalll not not be mathematically converted between units when determining conformance to a specification.
5.3 Zero Settin Setting g Most Most calipe calipers rs are equipp equipped ed with with the abilit ability y to adjustthe adjustthe zero point. For calipers with adjustable zero points, the metrological characteristics described in this Standard (see para. 5.10) 5.10 ) apply when the outside measuring faces faces are properly properly brought brought into contact contact with each other for zero setting. For calipers without an adjustable zero, e.g., some vernier calipers, there may be a nonzero error when the outside measuring faces are brought together. This error shall be included in the evaluation of the metrological characteristics without correction.
5.4 Indicatio Indication n
5.9 Specialty Specialty Calipers Calipers
The specified MPE values apply to any and all unique measurement indications made under reasonable use of the caliper. Averaging of several test values or other data treatment is not permitted when determining conformance to specifications.
A large variety of specialty calipers are commercially available for measuring items such as tubing, threads, specialized measuring face configurations for use in restrictedareas,large restrictedareas,large diameter diameter measuringfaces, measuringfaces, spherical spherical shaped shaped measur measuring ing faces, faces, and conica conicall measur measuring ing faces faces that that allow allow contac contactt with with surfac surfaces es that that maynot be flat flat or parall parallel. el. Specifications for specialty calipers shall be stated by the manufacturer and conform to the terms, definitions, and symbols employed in this Standard and ISO 13385-1.
5.5 Temperature All speci specific ficati ationsapplyat onsapplyat a rated rated operat operatingcondi ingconditio tion n of 20°C (68°F) unless otherwise specified. The effective nominal coefficient of thermal expansion (CTE) of a caliper in the temperature range 10°C to 30°C shall be ( 1 1 . 5 ± 1 . 0 ) × 1 0−6 /°C. If not, then the effective nominal CTE with its uncertainty shall be supplied by the manufacturer. Caliper specifications have a rated operating condition of 20°C (68°F); therefore, the test values observed in a verification test shall be corrected to 20°C (68°F) to obtain the error of indication that the caliper would have produced had the test been performed at 20°C (68°F). If temperature correction to 20°C (68°F) is not performed, this Standard allows the consequences to be included in the evaluation of the measurement uncertainty (see Nonmandatory Appendix C). C ).
5.10 Metrological Metrological Characteristics 5.10.1 General. General. ISO 13385-1 describes the important metrological characteristics for calipers. This Standard recognizes recognizes the following following metrological metrological characteristics characteristics as defined in ISO 13385-1: (a) partial surface contact error, E (b) repeatability of partial surface contact error, R (c) line contact error, L error, L (d) scale shift error, S (e) error due to crossed knife-edge distance, K Further description and default test methods for these metrological characteristics are in paras. in paras. 5.10.4 through 5.10.4 through 5.10.8.. These test methods provide sufficient testing to 5.10.8 demonstrate conformance to specification and do not change the requirements. As such, the test measurands are a finite set of possible errors of indication, and the valueof valueof each each measur measurandis andis estima estimatedby tedby a singletestvalue singletestvalue..
5.6 Measurement Uncertainty Uncertainty and Decision Rules Rules Unless Unless otherw otherwise ise stated stated,, the defaul defaultt decisi decision on rule when when determini determining ng the conformanc conformance e of a caliper caliper to specificat specifications ions is simple 4:1 acceptance in accordance with ASME B89.7.3.1. The measurement uncertainty shall be evaluated ated in acco accord rdan ance ce with with JCGM JCGM 100 (GUM (GUM)) and and ISO ISO 14253 14253-5. An example of determining conformance to specification is shown in Nonmandatory Appendix C, para. C-4.6. C-4.6 .
5.10.2 MPE Specifications. Specifications. Manufacturers of calipers shall shall state state MPE values values for the metrol metrologi ogical cal charac character terist istics ics in para. in para. 5.10.1, 5.10.1, and calipers shall conform to the stated
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ASME B89.1.14-2018
Table 5.8-1 Maximum Permissible Errors of Calipers With Measuring Range Up to 1 000 mm (40 in.) Analog Scale Interval or Electronic Digital Resolution Measured Length,
L
0.0005 in.
0.001 in.
0.01 mm
0.02 mm
0.05 mm
E MPE,
S MPE,
E MPE,
S MPE,
E MPE,
S MPE,
E MPE,
S MPE,
E MPE,
S MPE,
mm
in.
in.
in.
in.
in.
mm
mm
mm
mm
mm
mm
0 ≤ L ≤ 50
0 ≤ L ≤ 2
±0.0010
±0.0010
±0.001
±0.001
±0.02
±0.03
±0.02
±0.04
±0.05
±0.05
50 < L ≤ 100
2 < L ≤ 4
±0.0010
±0.0020
±0.001
±0.002
±0.03
±0.05
±0.04
±0.06
±0.05
±0.10
100 < L < L ≤ 150
4 < L ≤ 6
±0.0010
±0.0020
±0.001
±0.002
±0.03
±0.05
±0.04
±0.06
±0.10
±0.10
150 < L < L ≤ 200
6 < L ≤ 8
±0.0015
±0.0020
±0.002
±0.003
±0.03
±0.05
±0.04
±0.06
±0.10
±0.10
200 < L < L ≤ 300
8 < L ≤ 12
±0.0015
±0.0025
±0.002
±0.003
±0.04
±0.06
±0.04
±0.06
±0.10
±0.10
300 < L < L ≤ 400
12 < L ≤ 16
±0.0020
±0.0025
±0.002
±0.003
±0.04
±0.06
±0.04
±0.06
±0.10
±0.10
400 < L < L ≤ 500
16 < L ≤ 20
±0.0020
±0.0030
±0.002
±0.003
±0.05
±0.07
±0.06
±0.08
±0.10
±0.10
500 < L < L ≤ 600
20 < L ≤ 24
±0.0020
±0.0030
±0.002
±0.003
±0.05
±0.07
±0.06
±0.08
±0.15
±0.15
600 < L < L ≤ 700
24 < L ≤ 28
±0.0025
±0.0035
±0.003
±0.004
±0.06
±0.08
±0.06
±0.08
±0.15
±0.15
700 < L < L ≤ 800
28 < L ≤ 32
±0.0025
±0.0035
±0.003
±0.004
±0.06
±0.08
±0.06
±0.08
±0.15
±0.15
800 < L < L ≤ 1 00 0 00
32 < L ≤ 40
±0.0030
±0.0040
±0.003
±0.004
±0.07
±0.09
±0.08
±0.10
±0.15
±0.15
GENERAL GENERAL NOTE: Asdiscussed Asdiscussed in para paras. s. 5.10.4 5.10.4through through 5.10.8 5.10.8,, bydefault, bydefault,E E MPE limitvalueforerrors rs E , R,and L,and S MPE limitvaluefor MPE isthe limitvalueforerro MPE isthe limitvaluefor errors S and S and K.
MPE MPE valu values es.. Defa Defaul ultt MPE MPE valu values es are are show shown n in Table 5.8-1 5.8-1.. The default MPE values in Table in Table 5.8-1 are 5.8-1 are for calipers with a measuring range up to 1 000 mm (40 in.). These MPE MPE valu values es are are a func functi tion on of the the meas measur ured ed leng length th and and not not the measur measuring ing range range of the calipe caliper. r. For larger larger calipe calipers, rs, the MPE values will increase as the measured length increases. For simplicity in practical use, the MPE values increase in a stepwise manner. During conformance testing, the measured length is considered nominal when determining the MPE values, and the smaller MPE value always applies for test points that are nominally at the transition between the MPE values. For example, if a gage block used for testing is nominally 200 mm, but the calibrated value is 200.01 mm, the MPE for 200 mm still applies.
between the caliper indication and the reference value of the measurement standard. By default, the errors shall be compared to the E MPE MPE limit values in Table 5.8-1 when 5.8-1 when determining conformance. When testing for conformance to specification, the test points shall be approximately equally distributed across the measuring range of the caliper with a minimum number of test points in accordance with Table 5.10.41 . At least one test point shall be at a minimum of 90% of the measuring range. The test points shall be located on the measuring faces of the caliper at different distances from the beam. See Figure 5.10.4-1. 5.10.4-1. The partial surface contact errors intentional tionally ly detect detect a combin combinati ation on of the calipe caliperr scale scale errors errors as well as the parallelism and flatness of the outside measuring faces.
5.10.3 Test Points. Points. When testing for conformance to
5.10.5 5.10.5 Repeat Repeatabi ability lity of Partial Partial Surface Surface Contac Contactt Error, Error,
the MPE values of the caliper, sufficient test points shall be used to establish confidence in the results. Requirements for test points are found in paras. 5.10.4 through 5.10.8. 5.10.8 . The user is free to choose the test points within the limits of the requirements. When considering test points, appropriate consideration shall be given to the caliper design and operating conditions that may indicate the presence of shortlength cyclic or local errors. For dial calipers, test points shall be chosen that orient the pointer at various angles within the dial, e.g., the 0-, 90-, 180-, and 270-deg positions.
repeatabi abilit lity y of the parti partial al surfac surface e contac contactt error, error, R, R. The repeat is the closeness of agreement between the results of successive measurements of the partial surface contact error at any one position on the outside measuring faces under the same conditions of measurement. The repeatability is calculated as the maximum difference (range) between three repeat readings observed at any one of the test points, including the same nominal test point and same nominal location on the measuring faces. Sinc Since e the the spec specif ifie ied d MPE MPE valu values es of a cali calipe perr appl apply y to any any and all reasonable measured indications, repeatability issues are included in the test for the partial surface contact error using the outside measuring faces. There may be times where a specific assessment of the repeatabilit ability y isuseful. isuseful. This This isparticul isparticularl arly y thecasewherean issue issue with with repeat repeatabi abilit lity y is observ observed ed during during testin testing g of the partia partiall surface contact error.
5.10.4 Partial Surface Contact Contact Error, E . The partial surface contact error, E error, E , is the length error of indication when when measur measuring ing a length length standa standard rd with with small small faces faces,, e.g., e.g., a gage gage block, block, at anypositio anyposition n on theoutside theoutside measur measuringfaces ingfaces,, and at any position within the measuring range of the caliper. This error is calculated as the difference
3
ASME B89.1.14-2018
Table 5.10.4-1 Number of Test Points for Measuring Range,
M
5.10.7 5.10.7 Scale Scale Shift Shift Error, Error, S . Thescaleshift Thescaleshift error, error,S S ,isthe , isthe error error of indica indicatio tion n when when using using measur measuring ing faces faces other other than than the outside outside measuringfaces. measuringfaces. Afterfollowing Afterfollowing proper proper operaoperation tion andzerosetting andzerosetting with with theoutsidemeasu theoutsidemeasurin ring g faces faces,, this this error is calculated as the difference between the caliper indica indicatio tion n andthe refere referencevalue ncevalue of a measur measureme ement nt stanstandard when using any of the other available measuring faces, e.g., inside, step, and depth measurement. By default, the errors are compared to the S MPE MPE limit values in in Table 5.8-1 when 5.8-1 when determining conformance. After testing the partial surface contact errors, E , using the outside outside measuringfaces, measuringfaces, the scaleshift error,S error, S ,shallbe ,shallbe tested for conformance to specification for any other measuring measuring faces, faces, e.g., e.g., inside, inside, step, step, or depth depth measur measurement ement,, with at least one test point. The scale shift error for inside measurement measurement is defined for measured lengths over 20 mm (0.75 in.) and shall be tested using an appropriate inside measurement standard, e.g., a ring gage, a specially designed caliper checker, or a gage block stack with appropriate jaws. See Figure 5.10.7-1. 5.10.7-1. By default, the test point shall be between 20 mm and 50 mm (0.75 in. and 2 in.). The scale shift error using the depth or step measurement ment functi functionsshallbe onsshallbe testedusin testedusing g an approp appropria riate te length length standard located on a reference surface, e.g., a gage block on a surface plate. See Figures 5.10.7-2 and 5.10.7-2 and 5.10.7-3 5.10.7-3.. By default, the test point shall be less than 50 mm (2 in.).
E MPE
mm
in.
Minimum Number of Test Points
0 ≤ M ≤ 150
0 ≤ M ≤ M ≤ 6
3
150 < M < M ≤ 300
6 < M ≤ 12
4
300 < M < M ≤ 1 00 000
12 < M ≤ 40
5
GENERAL NOTE: For example, test points of 100, 200, 300, 300, 400, and 550mm would would satisf satisfy y thetest point point requir requireme ementsfor ntsfor a calipe caliperr with with a measuring range of 600 mm.
If not otherwise stated, the limit value for repeatability repeatability error, R, shal shalll be equa equall to the the rang range e ofthe stat stated ed E MPE MPE limit values values,, e.g., e.g., if E if E MPE ±0.03 3 mm, mm, then then the the MPE MPE for for R is 0.06 0.06 MPE = ±0.0 mm.By default,repeatab default,repeatabilityerror, ilityerror, R,shallbecomparedto the range of the E MPE limit values in Table in Table 5.8-1 5.8-1 when MPE determining conformance.
5.10.6 LineContact Error, Error, L. Thelinecontacterror, L, is the error error of indica indicatio tion n when when measur measuring ing a small small cylindr cylindrica icall measurement standard, e.g., a pin gage, at any position across the outside measuring faces. This error is calculated as the maximum difference (range) between the line contact contact errors errors observed observed at any position position on the outsid outside e measur measuring ing faces faces and at the same same nomina nominall positi position on in the measuring range of the caliper. If not otherwise stated, the limit value for line contact error, L, shal shalll be equa equall to the the rang range e of the the stat stated ed E MPE MPE limit values values,, e.g., e.g., if E if E MPE = ±0.0 ±0 .02 2 mm, mm , then th en the th e MPE MP E for fo r L is 0.04 0.04 MPE mm. By defaul default, t, line line contac contactt error, error, L, shal shalll be comp compar ared ed to the range of the E MPE limit values in Table in Table 5.8-1 5.8-1 when MPE determining conformance. The line contact error detects the effects of the parallelism of the outside measuring faces as well as any flatness error or localized wear. When testing for conformance to specification, the line contact error shall be tested at one position in the measuring range of the caliper. This is done by placing a small cylindrical measurement standard between the jaws as near as possible to the caliper’s beam, and then slowly moving the measurement standard towards the opposite end of the jaws jaws while while carefu carefully lly observ observing ing the calipe caliperr readin readings. gs. See Figure See Figure 5.10.6-1. 5.10.6-1. The range of the readings is the line contact error. Prior Prior to testin testing g for line line contac contactt error, error, assess assessmen mentt of the possibili possibility ty of wear or parallelis parallelism m issues issues by bringing bringing the outside outside measuring measuring faces faces together together and observi observing ng any light light gap betwee between n the two measur measuring ing faces faces is recomm recommend ended. ed. If wear or parallelism is not suspected, then additional testing of the line contact error with the cylindrical measurement standard may not be necessary.
5.10.8 Effect Due to Crossed Knife-Edge Knife-Edge Distance, Distance, K . An additional error of indication may occur when small cylindrical holes are measured on a caliper that has crossed knife-edge internal measuring faces. See Figure 5.10.8-1.. This error, K , is treated as another type of 5.10.8-1 scale shift error that applies when measuring an internal cylindrical measurement standard, e.g., a ring gage. If not otherwise stated, for calipers with a measuring rang range e up to and and inclu includi ding ng 300 300 mm (12 (12 in.) in.),, the the limi limitt valu value e for the error due to the crossed knife-edge distance, K , shal shalll be equa equall to the the stat stated ed S MPE limit values values for measur measured ed MPE limit lengths (diameters) from 5 mm to 300 mm (0.2 in. to 12 in.). By default, the values for K shall shall be compared to the S MPE MPE limit values in Table 5.8-1 when determining conformance. When testing for conformance to specification, a single test point is required. The default test point shall be at nominally 5 mm (0.2 in.) in diameter. See Figure 5.10.8-2.. 5.10.8-2 In this Standard, calipers with measuring ranges over 300 mm (12 in.) and crossed knife-edge internal measuring faces are not rated for the measurement of internal diameters smaller than 20 mm (0.75 in.).
4
ASME B89.1.14-2018
Figure 5.10.4-1 Testing Partial Surface Contact Error — Example Test Points on Two Calipers Showing Different Lengths and Different Distances From the Beam
Figure 5.10.6-1 Testing Line Contact Error
5
ASME B89.1.14-2018
Figure 5.10.7-1 Testing Scale Shift Error — Inside Measurement
Figure 5.10.8-1 Effect of Crossed Knife-Edge Internal Measuring Faces
Figure 5.10.7-2 Testing Scale Shift Error — Depth Measurement
Figure 5.10.8-2 Testing Scale Shift Error — Internal Measurement With Crossed Knife-Edge
Figure 5.10.7-3 Testing Scale Shift Error — Step Measurement
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ASME B89.1.14-2018
NONMANDATORY APPENDIX A GOOD OPERATING PROCEDURES A-1 GENERAL
A-1.5 Locking Device
This Appendix Appendix provides provides general general guidance guidance on good operoperating procedures involving calipers.
When When proper proper readin reading g of the instru instrumen mentt is hinder hindered,the ed,the lockin locking g devic device e shouldbe shouldbe used used topreservethe topreservethe readin reading g until until the tool can be read under better conditions.
A-1.1 Preparation
A-1.6 Optional Support
The measuring faces should be inspected for any damage damage or excessive excessive wear and thoroughly cleaned. Verify smooth movement of the slide along the bar. The zero reading of the measuring faces should be checked.
Whenusing largercalipers and more accurate accurate measuremeasurements are required, the use of a supporting stand is recommended. This allows the operator to have both hands free and generally increases the accuracy and repeatability of measurements.
A-1.2 Cleaning
A-2 VERNIER CALIPER
Prior to use, and again after use and prior to storage, measuring instruments should be cleaned to remove contaminants. Clean the measuring faces by inserting lint-free paper between them, lightly close, and pull the paper through. Calipers can be cleaned by using a soft brush or clean cloth and solvent. Care should be taken to prevent trapping of solvent in holes or crevices. Avoid spraying solvent directly on the dial or electronic digital display.
A-2.1 Zero Settin Setting g Prior to taking measurements, the zero point of the caliper must be established. Clean the measuring faces and close them by applying minimum, consistent force at the thumb roller or fine adjustment nut. Observe the graduations, and make sure the vernier plate zero lines are matched to the bar’s graduation. If not, the vernier plate may be adjusted to read zero. Usually, the vernier plate does not have to be reset after the initial setting.
A-1.3 Preservation For storage, shipment between facilities, or shipment from a facility to a calibration laboratory, measuring instruments should be coated with a corrosion preventative as soon as possible after cleaning operations. The corrosion preventative to be used will depend on the type of measuring instrument being stored or shipped. An approved rust-preventative (light, medium, or heavy) should be used. Close-tolerance gauging surfaces should be coated with an approved light preservative. Store the caliper with a gap between the outside measuring faces.
A-2.2 How to Read a Vernier Caliper Thefollowin Thefollowing g proces processs shouldbe shouldbe used used to correc correctlyread tlyread a vernier caliper: Step Step 1: From the the zero zero (0) (0) line line on the the vern vernie ierr plat plate, e, read read thewholeunitsof measur measure e from from themainscale, themainscale, on thebar, to the left of the zero (0) line. partiall units units of measur measure, e, if any, any, from from the Step Step 2: Addthe partia last whole unit on the main scale, on the bar, to the left of the zero (0) line of the vernier plate. Step Step 3: Add Add the the valu value e of the the unit unitss fromthe fromthe vern vernie ierr plat plate e line that corresponds corresponds to the vernier line that best aligns (coi (coinc ncid iden ent) t) to any any line line on the the adja adjace cent nt main main scal scale, e, on the the bar. Step4: Add thevalues thevalues from from Ste Steps ps 1, 2,and 3 forthe total total value of the measurement.
A-1.4 Fine Adjustment Adjustment Seat the measured part on the reference face, centralizing the part between the measuring faces. Apply minimum, consistent force at the thumb roller or fine adjustment nut. Better accuracy and repeatability can be obtained when the thumb roller or fine adjustment is used properly.
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ASME B89.1.14-2018
A-3 DIAL CALIPER CALIPER
A-4 ELECTRONIC DIGITAL DIGITAL CALIPER
A-3.1 A-3.1 Zero Setting Setting
A-4.1 A-4.1 Zero Setting Setting
Prior to taking measurements, the zero point of the caliper must be established. Clean the measuring faces and close them by applying minimum, consistent force at the thumb roller or fine adjustment nut. Observe the dial graduations, and make sure the hand lines up with the zero graduation. If not, the dial and bezel can be rotated to align zero by hand. The zero can be reset by adjust adjustingthe ingthe bezel bezel to a presetposit presetpositionor ionor to a standa standard, rd, so the dial will read the deviation from this position.
Prior to taking measurements, the zero point of the caliper must be established. Clean the measuring faces and close them by applying minimum, consistent force at the thumb roller or fine adjustment nut. Observe the digital display and confirm zero set or reset zero for the appropriate measurement mode as determined by the instrument design. The tool may have an absolute (ABS) mode for direct measurement, which requires a fixed origin, zero setting at the jaws-closed position. The incremental (INC) mode allows a floating zero to be set at any position along the range for comparison measurement.
A-3.2 How to Read a Dial Caliper Thefollowin Thefollowing g proces processs shouldbe shouldbe used used to correc correctlyreada tlyreada dial caliper: Step Step 1: Read Read the the whol whole e unit unitss of meas measur ure e from from the the main main scale bar to the left of the movable slide reference point. Step 2: Add the value of units from the dial scale line that lines up best with the dial hand or pointer. Step 3: Add the values from Steps from Steps 1 and 1 and 2 2 for for the total value of measurement.
A-4.2 How to Read an Electronic Digital Caliper Read Read the displa display y direct directly ly in units units of measur measure, e, observ observing ing the mode of the tool’s readout.
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ASME B89.1.14-2018
NONMANDATORY APPENDIX B ENVIRONMENTAL CONSIDERATIONS B-1 GENERAL GENERAL
same, the effect of the deviation from 20°C (68°F) is less than if the measured part and measuring instrument were of different materials.
This Appendix provides general guidance and awareness regarding the environmental considerations involving ving theuse of vernie vernier, r, dial, dial, andelectron andelectronic ic digita digitall calipe calipers. rs.
B-2.4 Differenc Differencee Due To Dissimilar Dissimilar Materials Materials If measur measured ed parts parts aremade of a materi material al other other than than that that used for the caliper (typically steel), an allowance for temperature differences, with reference to 20°C (68°F), must be considered and applied if necessary.
B-2 TEMPERATURE B-2.1 Reference Temperature Temperature Whenever precision measurements are made, the temperature should be as close to the standard reference temperature of 20°C (68°F) as possible. Since standards andmeasuri andmeasuring ng instru instrumen ments ts usuall usually y aremade of steel,they steel,they have the same nominal coefficient of expansion. For caliper measurements, control of thermal gradients and temperature stability are often the most important consideratio considerations ns for reliable measurement. Measurement application applicationss should consider a reasonable reasonable operating policy policy for maximum maximum deviationfrom deviationfrom standard standard temperatur temperature e and maximum temperature gradient.
B-2.5 Soak Time Time Measuring instruments should be stored in a constant temperature room before they are calibrated to ensure they they arenearly arenearly thesametemperat thesametemperatureas ureas themeasure themeasuremen ment t labora laborator tory. y. The amount amount of soak soak time time requir required ed depen depends ds on the size, shape, and mass of the measuring instrument along with the conditions of measurement and the desired accuracy. See ASME B89.6.2 for further information and example of estimating soak-out time.
B-2.2 Heat Transfer Transfer
B-3 HUMIDITY HUMIDITY
The amount of heat transfer due to the operator handling measuring instruments instruments or measured measured parts should should always be considered. The longer the operator handles items, the greater the potential for temperature differences. The amount of heat transferred can be minimized by using gloves, stands to isolate the measuring instruments, a normalizing plate, air circulation, or other means to thermally stabilize the measured part or the measuring instrument from the operator.
Therelativehumid Therelativehumidityof ityof theatmosphe theatmosphere re in a calibr calibrati ation on labora laborator tory y should should prefer preferabl ably y be kept kept at a level level that that would would minimize the possibility of corrosion. In general, the airconditioning system of a laboratory should remain in operation at all times because elevated humidity causes corrosion and delays occur while measuring instruments reach thermal equilibrium with the laboratory that is reopened.
B-4 CLEANLINESS CLEANLINESS
B-2.3 Working Temperature
Cleanl Cleanline iness ss is an import important ant requir requireme ement nt for a good good calicalibration bration laboratory laboratory.. Contamina Contamination tion and spurious spurious particles particles cause serious errors in precision measurements, bring about excessive wear of precision instruments, and degrade instrument performance.
When measuring instruments are used in production shops, working temperatures are seldom at the standard reference temperature. If the measuring instrument is accurate at the standard reference temperature, and if the coefficien coefficients ts of thermal thermal expansionof expansionof boththe measured measured part and measuring instrument are approximately the
9
ASME B89.1.14-2018
NONMANDATORY APPENDIX C MEASUREMENT UNCERTAINTY C-1 GENERAL
ment errors including any inherent repeatability are part ofwhat is being being testedand testedand notinclude notincluded d in theuncertai theuncertainty nty.. For this this exampl example, e, it is assume assumed d that that a reason reasonabl ably y skille skilled d operator is performing the verification verification test (this assumpassumption tion may may not not be vali valid d in all all case cases) s),, and and ther theref efor ore e no unce uncerrtainty contribution from the operator is included in the performance verification uncertainty statement because operator effects appear (hence are accounted for) in the observed error of indication.
This Appendix provides general guidance and awareness regarding the determination and application of measurement uncertainty when verifying the conformance of a caliper to stated specifications. The example given is for guidance only. The actual uncertainties will be different for each laboratory. The measurement uncertainty when using a caliper, e.g., to measure manufactured workpieces, is not within the scope of this Standard but is discussed in ASME B89.7.3.2.
C-3.3 Gage Block Size In this this exampl example, e, thecalibrat thecalibratedvalueof edvalueof thegageblocksis not not used used,, but but inst instea ead d the the nomi nomina nall size size mark marked ed on the the gage gage blocks is used as the reference value. The gage blocks are assume assumed d to be calibr calibrate ated d andwithin andwithin their their tolera tolerancegrade ncegrade..
C-2 SOURCES OF ERROR Common sources of error in mechanical calibrations include the uncorrected error and uncertainty in the master, repeatability, resolution, reproducibility, uncertainty in the temperature of the master, uncertainty in the temper temperatu ature re of the test test item, item, uncert uncertain ainty ty in the coeffi coeffi-cient of thermal expansion, elastic deformation, cosine errors, Abbe offset, and others, depending on the type of instrument or material standards being measured. Not all of these sources contribute to the measurement uncertainty in the calibration or verification of a caliper.
C-3.4 Temperature Correction Calipers are often tested in laboratories with average temperatures of approximately 20°C (68°F) and with some known approximate limits of thermal variation. In common practice, no correction for temperature is made, which must be addressed in the uncertainty, as shown in the example in section C-4. C-4.
C-3 COMMON PRACTICES PRACTICES
C-4 EXAMPLE UNCERTAINTY UNCERTAINTY BUDGET
C-3.1 General General
C-4.1 C-4.1 Digital Digital Caliper
The uncertainty budget presented in this Appendix is based based on common common practi practices ces used used in the calibr calibrati ation on of calicalipers. pers. Otherapproaches Otherapproaches may result result in differen differentt uncertaint uncertainty y contributors and values.
An example uncertainty budget for the performance verification of the partial surface contact error, E MPE MPE , on a 0-mm to 150-mm digital caliper is shown in Table C-4.1-1. C-4.1-1. In this example, the error of indication of the caliper is measured using calibrated gage blocks. The following assumptions and conditions apply: (a) measured length: 150 mm (b) caliper resolution: 0.01 mm (c) temperature range: 20°C ± 2°C (d) temperature difference: 0.5°C (e) caliper CTE: 11.5 × 10−6/°C ± 10% (f) gage block CTE: 10.2 × 10−6/°C ± 5% (g) gage block tolerance: Grade 0 (±0.4 μm) The temperatures of the caliper and gage block are assumed to be within the above temperature range during the verification test. The difference between the temperatures of the caliper and gage block is assumed
C-3.2 Performance Performance Verification This uncertainty budget is based on performance verificati fications ons,, where where the measur measured ed errors errors are compa compared red to the specification of the caliper and are not assigned values used as correction factors in later use of the caliper. In performance verification, each test value is an estimate of a differ differentmeasu entmeasuran rand d that that is theobservederror theobservederror of indiindicati cation on of the the cali calipe perr at the the mome moment nt of test testin ing, g, obta obtain ined ed at, at, or corrected to, the rated operating condition of 20°C (68°F). The measurement uncertainty addresses the uncertainty in the test value and does not address the compre comprehen hensiv sivene eness ss of the test. test. In this this manner manner,, the instruinstru-
10
ASME B89.1.14-2018
to not exceed exceed the above above limit limit for the temperat temperature ure difference.
Based on the values in para. C-4.1, C-4.1, = 11.5
10.2 = 1.3 × 10
6
/°C
C-4.2 Reference Standard and applying this to the equation in para. C-4.3.1, C-4.3.1,
The calibrated values of the gage blocks are not used, andit is assume assumed d that that the blocks blocks are within within the tolera tolerance ncess for a Grade 0 set. A rectangular distribution is assumed with a limit of 0.4 μm.
L =
0.39 m
It is determ determine ined d that that due to handli handling, ng, the temper temperatu atures res ofthecaliperandthegageblockscouldbeasmuchas0.5°C apart. The uncertainty caused by this temperature difference can be expressed as:
temperature for dimensional measurements is 20°C (68°F). The uncertainty in correcting the caliper and gage blocks to 20°C (68°F) due to the uncertainty in knowing the coefficient of thermal expansion can be expressed by the following equation: L(20
=
C-4.4 Temperature Difference
C-4.3.1 General Equation. The standard reference
=
10 6/°C)
×
The distribution is assumed to be rectangular for the purposes of this example.
C-4.3 Deviation from Reference Reference Temperature
L
(150 mm ) ( 2°C ) ( 1. 1.3
L
T )
=
L
t
where L = nominal nominal length length α α = average average CTE of the gage blocks and and caliper caliper Δt t = difference in temperature between the gage blocks and caliper caliper
where nominal length length L = nominal temperature T T = temperature Δα α = difference difference in the CTE between the gage blocks and caliper
Based on the values in para. C-4.1, C-4.1, The difference in the CTE of the gage blocks and the caliper is a combination of the nominal difference and the associated uncertainties.
L =
uncertainty in the CTE of any material. For this example, the gage blocks and caliper are made from different types of steel. The caliper has a CTE of 11.5 × 10 −6 /°C, which is assumed to be within ±10%. The gage blocks have a CTE of 10.2 × 10−6 /°C, which is stated by the manufacturer to be within ±5%. (a) Applyin Applying g the equationin equationin para para.. C-4.3 C-4.3.1 .1 forthecaliper CTE:
×
10 6/°C)
=
0.81 m
=
Using the values determined in paras. in paras. C-4.2, C-4.2 , C-4.3.2 C-4.3.2,, C4.3.3,, and 4.3.3 and C-4.4 C-4.4,, the associ associate ated d standa standard rd uncert uncertain aintie tiess are estima estimatedas tedas shown shown in TableC-4.1-1 TableC-4.1-1.. Thecombinedunce Thecombineduncerrtainty, u tainty, u c, is then calculated as follows: u
c
=
(0.232
=
0.61
+
2
0.20
+
2
0.09
+
2
0.23
+
2
0.47
1/ 2
)
m
The expanded expanded uncertaint uncertainty, y, U , usin using g a cove covera rage ge fact factor or,, k = 2, is calculated as follows:
in para. C-4.3.1 for C-4.3.1 for the gage (b) Applying the equation in para. block CTE:
(150 mm ) ( 2°C )( )( 0 .5 .51
10 6/°C)
C-4.5 Combined and Expanded Expanded Uncertainty Uncertainty
)( 1 .1 .15 × 10 6/°C) = 0.35 m = (150 mm ) ( 2°C )(
L =
×
The distribution is assumed to be rectangular for the purposes of this example.
C-4.3.2 Uncertainty Uncertainty in Nominal CTE. There is some
L
(150 mm ) ( 0. 0.5°C ) ( 1 0. 0.85
=
0.15 m
2uc
=
1.2
m
The distri distribut bution ionss are assume assumed d to be rectan rectangul gular ar for the purposes of this example.
C-4.6 Conformance Conformance Test (Application of Decision Decision Rule)
C-4.3.3 C-4.3.3 Nominal CTE Difference Difference.. If the nominal CTEs
The maximum maximum permissib permissible le partial partial surface surface contact contact error listed in Table 5.8-1 for 5.8-1 for a 150-mm measured length is 0.03 0.030 0 mm. mm. If the the defa defaul ultt deci decisi sion on rule rule of simp simple le 4:1 4:1 acce accepptance in accordance with ASME B89.7.3.1 is being employed, then the expanded uncertainty, U , must be less than 25% of the MPE value. In this case, the uncertain taintyof tyof 1.2 1.2 μm isonly4% ofthe MPE MPE valu value,and e,and ther theref efor ore e a conformance decision can be made. If the largest observ observed ed error error does does not exceed exceed the MPE, MPE, and the decisi decision on
of the caliper and gage blocks are different, as in this example, then the following equation is applicable: =
C
GB
where nominal CTE of the caliper caliper α C C = nominal α GB = nominal nomi nal CTE of the gage gage block GB
11
ASME B89.1.14-2018
Table C-4.1-1 Uncertainty Budget for Performance Verification of the Partial Surface Contact Error for a 0-mm to 150-mm Digital Caliper Estimated Limit, μm
Type
Distribution
Divisor
Standard Uncertainty, μm
Gage block tolerance
0.40
B
Rectangular
1.73
0.23
Uncertainty in caliper CTE
0.35
B
Rectangular
1.73
0.20
Uncertainty in gage block CTE
0.15
B
Rectangular
1.73
0.09
Nominal CTE difference
0.39
B
Rectangular
1.73
0.23
Temperature difference
0.81
B
Re Rectangular
1.73
0.47
Uncertainty Source
GENERAL GENERAL NOTE: The expanded expanded (k (k = = 2) uncertainty is equal to 1.2 μm.
C-5 CONCLUSION CONCLUSION
rule is satisfied, then acceptance can be stated, e.g., in tolerance. If the largest observed error exceeds the MPE, and the decision rule is satisfied, then rejection can be stated, e.g., out of tolerance.
The format for an uncertainty budget does not need to beas show shown n in Table C-4.1C-4.1-1 1. It isonlyneces isonlynecessa sary ry tolistthe sources sources of uncertaint uncertainty y and the standarduncertain standarduncertainties ties,, and explain how they were obtained. The table may contain two columns or as many as are needed.
12
B89 AMERICAN NATIONAL STANDARDS FOR DIMENSIONAL METROLOGY AND CALIBRATION OF INSTRUMENTS
B89-1 9-1990 990
Space pace Pla Plate Tes Test Reco Recom mmenda endati tio ons for for Coor oordina dinate te Meas easurin uring g Machi achine ness (Tech Techn nical ical Pap Paper) er)
B89 B89 Repo Report rt-1 -199 990 0
Para Parame metr tric ic Cali Calibr brat atio ion n of Coor Coordi dina nate te Meas Measur urin ing g Mach Machin ines es (Tec (Techn hnic ical al Pape Paper) r)
B89. B89.1. 1.2M 2M-1 -199 991 1
Cali Calibr brat atio ion n of Gage Gage Bloc Blocks ks by Cont Contac actt Comp Compar aris ison on Meth Method odss (Thr (Throu ough gh 20 in. in. and and 500 500 mm) mm)
B89.1 B89.1.5.5-199 1998 8 (R2014 (R2014))
Measur Measureme ement nt of Plain Plain Extern External al Diame Diameter terss for Use as Maste Masterr Discs Discs or Cylind Cylindric rical al Plug Plug Gag Gages es
B89. B89.1. 1.66-20 2002 02 (R20 (R2017 17))
Meas Measur urem emen entt of Plai Plain n Inte Intern rnal al Diam Diamet eter erss for for Use Use as Mast Master er Ring Ringss or Ring Ring Gage Gagess
B89. B89.1. 1.77-20 2009 09 (R20 (R2014 14))
Perf Perfor orma manc nce e Stan Standa dard rd for for Stee Steell Meas Measur urin ing g Tape Tapess
B89.1 B89.1.8.8-201 2011 1 (R2016 (R2016))
Perfor Performan mance ce Evalua Evaluatio tion n of Displa Displacem cement ent-M -Meas easuri uring ng Laser Laser Interf Interfero eromet meters ers
B89.1.9-2002 (R2012)
Gage Blocks
B89. B89.1. 1.10 10MM-20 2001 01 (R20 (R2016 16))
Dial Dial Indi Indica cato tors rs (for (for Line Linear ar Meas Measur urem emen ents ts))
B89.1.13-2013
Micrometers
B89.1.14-2018
Calipers
B89. B89.1. 1.17 17-2 -200 001 1 (R20 (R2017 17))
Meas Measur urem emen entt of Thre Thread ad Meas Measur urin ing g Wire Wiress
B89. B89.3. 3.11-19 1972 72 (R20 (R2003 03))
Meas Measur urem emen entt of OutOut-of of-R -Rou ound ndne ness ss
B89. B89.3. 3.44-20 2010 10 (R20 (R2015 15))
Axes Axes of Rota Rotati tion on:: Meth Method odss for for Spec Specif ifyi ying ng and and Test Testin ing g
B89.3.7-2013
Granite Surface Plates
B89.4. 9.4.1 1-19 -1997
Meth ethods ods for for Per Perform forma ance nce Eva Evaluat luatiion of Coo Coordin rdina ate Measur asurin ing g Mach achines nes
B89.4 B89.4.10 .10-20 -2000 00 (R2011 (R2011))
Method Methodss for Perfor Performa mance nce Evalua Evaluatio tion n of Coordi Coordinat nate e Measu Measurin ring g System System Softw Software are
B89.4 B89.4.19 .19-20 -2006 06 (R2015 (R2015))
Perfor Performan mance ce Evalua Evaluatio tion n of LaserLaser-Ba Based sed Spheri Spherical cal Coordi Coordinat nate e Measur Measurem ement ent Syste Systems ms
B89.4 B89.4.22 .22-20 -2004 04 (R2014 (R2014))
Method Methodss for Perfor Performa mance nce Evalua Evaluatio tion n of Articu Articulat lated ed Arm Coord Coordina inate te Measu Measurin ring g Machin Machines es
B89.4 B89.4.10 .10360 360.2.2-200 2008 8 (R2012 (R2012))
Accept Acceptanc ance e Test Test andReverif andReverifica icatio tion n Test Test forCoordi forCoordinat nate e Measu Measurin ringMachi gMachines(CM nes(CMMs Ms)) –Part2: CMMsUsed CMMsUsed for Measuring Linear Dimensions
B89. B89.6. 6.22-19 1973 73 (201 (2017) 7)
Temp Temper erat atur ure e and and Humi Humidi dity ty Envi Enviro ronm nmen entt for for Dime Dimens nsio iona nall Meas Measur urem emen ent t
B89. B89.7. 7.11-20 2016 16
Guid Guidel elin ines es for for Addr Addres essi sing ng Meas Measur urem emen entt Unce Uncert rtai aint nty y in the the Deve Develo lopm pmen entt and and Appl Applic icat atio ion n of ASME ASME B89 B89 Standards (Technical Report)
B89.7.2-2014
Dimensional Measurement Planning
B89.7 B89.7.3. .3.1-2 1-2001 001 (R2011 (R2011))
Guidel Guideline iness for Decisi Decision on Rules: Rules: Consi Consider dering ing Measu Measurem rement ent Uncert Uncertain ainty ty in Deter Determin mining ing Confo Conforma rmance nce to Specifications
B89.7 B89.7.3. .3.2-2 2-2007 007 (R2016 (R2016))
Guidel Guideline iness for the Evalua Evaluatio tion n of Dimens Dimensio ional nal Measu Measurem rement ent Uncert Uncertain ainty ty (Techn (Technica icall Report Report))
B89.7 B89.7.3. .3.3-2 3-2002 002 (R2017 (R2017))
Guidel Guideline iness for Assess Assessing ing the Reliab Reliabili ility ty of Dimens Dimensio ional nal Measur Measureme ement nt Uncert Uncertain ainty ty Statem Statement entss
B89.7 B89.7.4. .4.1-2 1-2005 005 (R2016 (R2016))
Measur Measureme ement nt Uncert Uncertain ainty ty and Confo Conforma rmance nce Testin Testing: g: Risk Risk Analys Analysis is (Techn (Technica icall Repor Report) t)
B89.7 B89.7.5.5-200 2006 6 (R2016 (R2016))
Metrol Metrolog ogica icall Tracea Traceabil bility ity of Dimen Dimensio sional nal Measu Measurem rement entss to the SI Unit Unit of Length Length (Techn (Technica icall Report Report))
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ASME B89.1.14-2018
