1、ASME B89.1.2M-1991 Calibration of Gage Blocks by Contact Comparison Methods (Through 20 in. and 500 mm) AN AMERICAN NATIONAL STANDARD The Anierican Society of Mec tia i7 ica I E ng i n ee rs ASME B89.1.2M 91 m O759670 05Y2700 375 = AN AMERICAN NATIONAL STANDARD Calibration of Gage Blocks by Contact
2、Comparison Methods (Through 20 in. and 500 mm) ASME B89.1.2M-I991 The American Society of Mechanical Engineers 345 East 47th Street, New York, N.Y. 10017 Date of Issuance: November 30, 1991 This Standard will be revised when the Society approves the issuance of a new edition. There will be no addend
3、a or written interpretations of the re- quirements of this Standard issued to this edition. The next edition of this Standard is scheduled for publication in 1994. ASME is the registered trademark of The American Society of Mechanical Engineers. This code or standard was developed under procedures a
4、ccredited as meeting the criteria for American National Standards. The Consensus Committee that approved the code or standard was balanced to assure that individuals from competent and concerned interests have had an opportunity to participate. The proposed code or standard was made available for pu
5、blic review and comment which provides an opportunity for additional public input from industry, academia, regulatory agencies, and the public-at-large. ACME does not “approve,“ “rate,“ or “endorse“ any item, construction, proprietary device, or activity. ASME does not take any position with respect
6、 to the validity of any patent rights asserted in connection with any items mentioned in this document, and does not undertake to insure anyone utilizing a standard against liability for infringement of any applicable Letters Patent, nor assume any such liability. Users of a code or standard are exp
7、ressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, is entirely their own responsibility. Participation by federal agency representative(s) or person(s) affiliated with industry is not to be interpreted as government or industty e
8、ndorsement of this code or standard. ASME accepts responsibility for only those interpretations issued in accordance with governing ASME procedures and policies which preclude the issuance of interpretations by individual vol- unteers. No part of this document may be reproduced in any form, in an el
9、ectronic retrieval system or otherwise, without the prior written permission of the publisher. Copyright O 1991 by THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS All Rights Reserved Printed in U.S.A. ASME B89-L-ZM 91 m 07.59670 0542702 148 m . FOREWORD (This Foreword is not part of ASME B89.1.2M-1991)
10、 ASME Standards Committee B89 on Dimensional Metrology, under procedures approved by the American National Standards Institute, has the responsibility of preparing standards which encompass the inspection and the means of measuring characteristics of various geo- metrical parameters such as diameter
11、, length, flatness, parallelism, concentricity, taper, and squareness. Comments and suggestions for improvement of this Standard are welcomed. They should be addressed to: ASME Standardization Dept. (M/S 8E) United Engineering Center 345 East 47th Street New York, NY 10017 This edition was approved
12、as an American National Standard by ANSI on July 22, 1991. . 111 ASME B89.L.2M 91 m 0759670 0542703 084 m ASME STANDARDS COMMITTEE B89 DIMENSIONAL METROLOGY (The following is the roster of the Committee at the time of approval of this Standard.) OFFICERS B. R. Taylor, Chairman F. G. Parsons, Vice-Ch
13、airman P. D. Stumpf, Secretary COMMITTEE PERSONNEL A. M. Bratkovich, National Machine Tool Builders Assoc., McLean, Virginia J. B. Bryan, Bryan Associates, Pleasanton, California A. K. Chitayat. Anorad Corp., Hauppauge, New York W. E. Drews, Rank Precision Industries, Inc., Des Plaines, Illinois C.
14、B. Erickson, Sterling Die Operation, West Hartford, Connecticut M. F. A. Fadl, Consultant, Providence, Rhode Island R. D. Farley, Lincoln Gage Co., Warren, Michigan M. B. Grant, Cummins Engine Co., Columbus, Indiana R. B. Hook, Metcon. Coventry, Rhode Island F. L. Jones, USATSG, Redstone Arsenal, Al
15、abama A. A. Lindberg, Moore Special Tool Co., Inc., Bridgeport, Connecticut E. G. Loewen, Milton Roy Co., Rochester, New York T. Mukaihata, Hughes Aircraft Co., EI Segundo, California D. Pieczulewski, A. G. Davis Gage and Engine Co., Hazel Park, Michigan L. K. Reddig, AGMC/MLDA, Newark, Ohio E. L. W
16、atetet, Consultant, Warwick, Rhode Island W. A. Watts, Glastonbury Gage, Glastonbury, Connecticut J. H. Worthen, Consultant, Durham, New Hampshire R. B. Zipin, Eli Whitney Metrology Lab, Dayton, Ohio PERSONNEL OF SUBCOMMITTEE 1 - LENGTH E. L. Watelet, Chairman, Warwick, Rhode Island A. K. Chitayat,
17、Anorad Corp., Hauppauge, New York E. G. Loewen. Milton Roy Co., Rochester, New York PERSONNEL OF WORKING GROUP 1.2 - MEASUREMENT OF GAGE BLOCKS BY COMPARISON METHODS G. B. Webber. Chairman, L. S. Starrett Co., Westlake, Ohio G. G. Erickson, Sterling Die Operation, West Hartford, Connecticut D. D. Fr
18、iedel, L. S. Starrett Co., Westlake, Ohio V ASME B89.1-2M 91 - 0759670 0542704 TIO CONTENTS . Foreword 111 Standard Committee Roster . v 1 2 3 4 5 6 7 8 9 10 11 Scope . 1 Objective 1 Units of Measure 1 Environment 1 Measuring Instrument 2 Preparation of Gage Blocks 4 Procedures for Measurement of Le
19、ngth and Parallelism . 5 Flatness. Surface Texture. and Wringing Quality 6 Accuracy of Calibrations 8 Certificate of Calibration 9 Gage Block Geometry 2 Figures 1 Gage Block Reference Points 3 2 Flatness Test . 7 Table 1 Allowable Measurement Uncertainty 8 Appendices A General 11 B Calibration Corre
20、ctions . 13 C Gage Block Tolerances . 23 D Measuring Instrument 27 Figures B1.1 B1.2 B1.3 B1.4 B1.5 B1.6 Deformation of Ball and Plane . Diamond vs . Tungsten Carbide Deformation of Ball and Plane - Diamond vs . Chrome Carbide . Deformation of Ball and Plane - Diamond vs . 52100 Steel . Deformation
21、of Ball and Plane - Diamond vs . 52100 Steel . Deformation of Ball and Plane - Diamond vs . Tungsten Carbide Deformation of Ball and Plane - Diamond vs . Chrome Carbide . 15 16 17 18 19 20 vii ASME BBq.L.2M 91 = 0759b70 0542705 957 Tables B2.1 Coefficients of Linear Thermal Expansion 21 C1 Tolerance
22、s on Length for Gage Blocks (Inch System) 24 C2 Tolerances on Length for Gage Blocks at the Reference Point (Metric System) . 25 C3 Tolerances on Flatness. Parallelism. and Surface Texture of Gaging Surfaces . 25 . v111 ASME B89.1.2M-1991 CALIBRATION OF GAGE BLOCKS BY CONTACT COMPARISON METHODS (THR
23、OUGH 20 IN. AND 500 MM) 1 SCOPE This Standard covers procedures to establish unified practice in calibration laboratories for measuring gage blocks up to 20 in. (500 mm) in length (size) by contact comparison methods. It does not cover interferometric comparison methods. 2 OBJECTIVE To establish an
24、American standard for laboratory cal- ibration of gage blocks by contact type comparison for tolerance Grade 3 (formerly A and B), Grade 2 (for- merly A+), and Grade 1 (formerly AA), as defined in Federal Specifications GGG-G- 15C, and ANSUASME B89.1.9M, when such calibration is traceable to NBS cal
25、ibrated master blocks. This Standard provides procedures for measuring the length and parallelism of used gage blocks required for recalibration and for measuring the length and parallel- ism of new gage blocks requiring certification. Procedures for determination of flatness, surface tex- ture, and
26、 wringing quality are provided, to be used only for new gage blocks or for used gage blocks when spec- ified. 3 UNITS OF MEASURE 3.1 Inch Unit of Length ters (mm) in the Metric System. The inch unit of length equals exactly 25.4 millime- 3.2 Microinch Unit One microinch equals one millionth (O.OOOOO
27、1) of an inch. 3.3 Metric Equivalents The metric equivalents used parenthetically after inch values in this Standard are not necessarily exact con- versions, but are the most convenient or rounded off val- ues. 3.4 Micrometer Unit The metric unit representing one millionth (11 l,O,OOO) of a meter wa
28、s formerly expressed as one “micron,” and identified symbolically by the Greek let- ter p (mu). It has been replaced by the name “microm- eter” and identified by the symbol pm. For reasons of clarity the word “micrometer” is always spelled out in this Standard. One microinch equals 0.0254 microme- t
29、er. 4 ENVIRONMENT 4.1 Cleanliness Cleanliness must be maintained in the immediate vi- cinity of the measurement being performed. The critical surfaces of the master gage block, the gage block being calibrated, and the measuring equipment must be clean and free of foreign matter and dust particles. 4
30、.2 Temperature The international standard temperature, at which the actual length of a gage equals its nominal length, is 68F (20C). The actual temperature of test gage block, ref- erence gage block, and instrument, must be known if accurate and reliable calibrations are to be achieved. The calibrat
31、ion accuracy may suffer when the ambient temperature departs from standard, by an amount de- pending on the temperature difference and its rate of change, the length of the gage blocks, the materials of which they are made, and the accuracy of the coeffi- cients of thermal expansion used in making c
32、orrections. Conditions will be improved by thermal shielding of the measuring station, the use of a soaking plate, and the knowledge of the exact temperature of the test block and reference block as determined by temperature mea- suring devices. 1 ASME B87-L.2M 71 0757670 05q2707 72T ASME B89.1.2M-1
33、991 CALIBRATION OF GAGE BLOCKS BY CONTACT COMPARISON METHODS (THROUGH 20 IN. AND 500 MM) It follows that, in order to achieve the level of accu- racy required for the calibration of gage blocks, the de- viation of the environmental ambient temperature from the standard must be held to a minimum. A s
34、uggested maximum is f 0.5“F (0.25“C) or less. For a complete analysis of the subject, refer to ANSI B89.6.2-1973, Temperature and Humidity Environment for Dimen- sionai Measurement. 4.3 Humidity It is recommended that the relative humidity in the measuring environment shall not exceed 45 % . Humid-
35、ity significantly beyond that value may cause problems with rusting of iron and steel surfaces, and cause per- sonne1 discomfort. 4.4 Vibration erence gage block at 68F (20C). When the test block and reference are of different materials, corrections must be made for differential deformation, and for
36、 differential thermal expansion when the temperature of the blocks differ from standard. (Refer to B1 and B2.) 5.4 The parallelism of the gaging surfaces is the greatest difference in length obtained from scanning the gaging surfaces with mechanical contacts (see para. 8.6.) 5.5 Flatness The flatnes
37、s of a gaging surface is the distance be- tween two theoretical parallel planes with minimum separation which envelop the gaging surface. Excessive mechanical vibration in the measurement laboratory may seriously affect the accuracy required for gage block measurement by causing instability at the p
38、oint of measurement and at the readout. Vibration should be minimized by locating the laboratory away from vibration sources and by using insulating mount- ings for measuring equipment. An ideal solution, used by some laboratories, is to support all measuring equip- ment on a massive floating subflo
39、or isolated from the surrounding structure, the building foundation and the work floor. 5 GAGE BLOCK GEOMETRY 5.1 Shape Gage blocks are made in three cross sectional shapes: rectangular, square and round, with and without holes (see Fig. 1). 5.2 Reference Points 6 MEASURING INSTRUMENT 6.1 Design The
40、 measuring instrument shall consist of a compar- ator and readout specifically designed to measure the length of a gage block between the top and bottom ref- erence points by comparison with a reference gage block, and shall meet the requirements stated in paras. 6.2 and 6.3, over its full range. Th
41、e instrument may consist of one of, but not limited to, the following: (u) Type A. A comparator with dual opposed matched upper and lower gage heads, platen and read- out. The readout indicates the differential of the move- ments of the upper and lower gage head contacts. The platen is used to suppo
42、rt the gage blocks being measured and is not a reference. (b) Type B. A comparator with a single lower gage head, adjustable upper reference contact, platen and readout. The measuring system floats with respect to a fixed platen which supports the gage blocks and is not a reference. The reference po
43、int is a point located in the plane of each gaging surface. The top reference point is located for each shape in relation to the size marking as shown in Fig. 1. The bottom reference point is the mirror im- age of the top reference point. (c) Type C. A comparator with a single upper gage head and a
44、lower platen having a flat, serrated, or dual track configuration. The platen is the lower reference. (Refer to para. A5.) 6.2 Functional Requirements 5.3 Gage Block Length 6.2.1 Alignments The mechanical length of a gage block, for the tol- erance grades l, 2, and 3 is the length perpendicular to o
45、ne gaging surface and between the two reference points. The length is obtained by comparison to a ref- It is not the intent of this Standard to specify the nec- essary alignments and geometry of the components in- volved in the measuring instrument, since these factors are inherent in the accuracy a
46、ttainable. The manufac- 2 ASME B89*1*2M 91 0759b70 0542708 bbb CALIBRATION OF GAGE BLOCKS BY CONTACT COMPARISON METHODS (THROUGH 20 IN. AND 500 MM) 1/2 distance between edge of 1 hole and edge of block (z$ o. 100“ 112 diameter e v t Reference Point, Round 112 deDth 112 depth ./ Reference Point, 1 /2
47、 distance between edge y/ of block and edge of hole A ASME B89.1.2M-1991 across the depth and along the width, and midway between the edges. Readings are taken on square style gage blocks along the width, midway be- tween the hole or edge of the countersink, and the edge of the gage on each of four
48、sides excluding 0.020 in. (0.05 mm) at the edges of the faces. This procedure does not preclude the checking of par- allelism by optical interference methods. The results of the measurement of parallelism are re- ported as the difference between maximum and mini- CALIBRATION OF GAGE BLOCKS BY CONTAC
49、T COMPARISON METHODS (THROUGH 20 IN. AND 500 MM) mum readings and should be within tolerances specified in Table C3. 9 FLATNESS, SURFACE TEXTURE, AND WRINGING QUALITY Normal calibration of used gage blocks by metrology laboratories covers only the reporting of gage length de- viation from nominal size and parallelism. The follow- ing procedures for determination of flatness, surface texture, and wringing quality are done only for accep- tance testing of new gage blocks or when, and as spec- ified for, used gage blocks. Before performing each of the following tests, each gage bloc
