1、AMERICAN NATIONAL STANDARD Measurement of Out - Of - Roundness ANSI 689.3.1 - 1972 REAFFIRMED 1997 FOR CURRENT COMMKEE PERSONNEL PLEASE SEE ASME MANUAL AS-1 1 SECRETARIAT THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS PUBLISHED BY THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS United Engineering Center
2、345 East 47th Street New York, N. Y. 100 17 No pan of this document may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior written permission of the publisher. Copyright 0. 1972 by THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS Printedin U.S.A. FOREWORD This F
3、oreword is not a part of American National Standard Measurement of Out-of-Roundness, ANSI B89.3.1. At the October 29, 1958 meeting of the American Standards B46 committee on “Surface Texture” a special subcommittee was formed to investigate the definition and usage of surface waviness specifications
4、, particularly the application to round parts. The subcommittee first met on February 19, 1959 and determined in this and subsequent meetings that the specification and measurement of out-of-roundness was the most important task. Conferences on the Unification of Engineering Standards in June, 1960
5、and September, 1962. Exploratory discussions and coordination of approaches were held at The American British Canadian In June, 1963, the ASA B89 Committee was formed to investigate and standardize the metrological aspects of dimension, geometry and form and the functions and personnel of the B46 su
6、bcommittee were transferred to the B89.3 Geometry Subcommittee Working Group 1 “Roundness”. At this point, an attempt was made to develop a unified approach to the centers and axis concepts for out-of-roundness measurement purposes and the similar concepts used for concentricity, effective size, and
7、 other feature characteristics being explored by other B89 Working Groups. However, after a considerable period of study, this approach proved to be impractical. A series of draft standards were prepared beginning in 1965 in which the out-of-roundness charac- teristic and criteria are not necessaril
8、y related to other concepts. The British Standard 3730: 1964 “Methods for the Assessment of Departures from Roundness” follows a similar approach. The final draft of the proposal was approved by the ANSI B89 Sectional Committee by letter ballot, on November 19, 1971. Upon approval by the sponsors, t
9、he final draft was approved by the American National Standards Institute on August 1-4, 1972. Suggestions for improvement gained in the use of this standard will be welcome. They should be sent to the American National Standards Institute, Inc., 1430 Broadway, New York, New York 10018. 111 . AMERICA
10、N NATIONAL STANDARDS COMMITTEE B89 DIMENSIONAL METROLOGY (The following is the Roster of the Committee at the time of approval of this Standard) OFFICERS E. G. Loenren, Chairman J. K. Emery. 1st Vice-chairman J. C. Moody, 2nd Vicechairman Mary Horkins. Executive Secretary AEROSPACE INDUSTRIES ASSOCI
11、ATION OF AMERICA, INC. M. J. bight, Metrology Section, Primary Standards Laboratories, Hughes Aircraft Company, Culver City, California AMERICAN ORDNANCE ASSOCIATION J. C. Moody, Sandia Corporation, Albuquerque, New Mexico AMERICAN SOCIETY FOR QUALITY CONTROL John Novomjr, Spew Gyroscope, Great Neck
12、, New York AMERICAN SOCIETY FOR TESTING AND MATERIALS H. J. stremba. Associate Director, Technical Operations, AST these radii are to be measured from a common point, selected as one of the centers referred to in paragraphs 2.8 and 2.9. The unit of measurement shall be inches, unless otherwise speci
13、fied. 1 AMERICAN NATIONAL STANDARD MEASUREMENT OF OUT-OF-ROUNDNESS ANSI 889.3.1-1972 2.7.1 Nicks,. Scratches, Etc. Nicks, scratches, or other random flaws are not normally included in the assessment of the measured profile; special notes on the drawing or specification should be used to control thes
14、e irregularities. 2.8 Centers for Out-Of-Roundness Measurement The centers of the measured polar profile which may be used to determine the out-of-roundness value when specified are those related to one of the follow- ing alternative methods of out-of-roundness assess- ment: 2.8.1 Minimum Radial Sep
15、aration (MRS). This center is that for which the radial difference between two concentric circles whichjust contain the measured polar profile is a minimum. 2.8.2 Least Squares Center (LSC). This center is that of a circle from which the sum of the squares of the radial ordinates of the measured pol
16、ar profile has a minimum value. 2.8.3 Maximum Inscribed Circle (MIC).This center is that of the largest circle which can be inscribed within the measured polar profile. 2.8.4 Minimum Circumscribed Circle (MCC). This center is that of the smallest circle which will just contain the measured prfile. 2
17、.9 Preferred Center The center from which the out-of-roundness value shall be determined unless specified otherwise is the Minimum Radial Separation Center. 3 SPECIFICATION AND DESIGNATION OF OUT- OF-ROUNDNESS 3.1 Lack of Roundness Specification Where no out-of-roundness value is specified, it shall
18、 be assumed that the surface profile produced is This is also known as the center for minimum Total Indi- cator Reading (TIR). The British Standards Institution publication 3730:1964 refers to it as Minimum Zone Center (MZC). This is also known as the plug gage center and is generally used for inter
19、nal diameters. This is also known as the ring gage center and is generally used for external diameters. See Section 5, Instruments. satisfactory. If the out-of-roundness of the surface is critical, the out-of-roundness value should be specified. 3.2 Roundness Statement and Symbol An out-of-roundness
20、 specification statement, such as, “This surface must be round within - - - - inches,” shall mean that any cross section covered by that specification shall be measured in a plane whose posi- tion is specified in paragraph 4.1, and shall have an out-of-roundness value as defined in this standard equ
21、al to or less than that specified. 3.2.1 Roundness Symbol. The symbol for round- ness as shown in Fig. 1 and Fig. 2, is an extension of the geometric characteristic symbols used for feature control in American National Standard Y14.5-1966, “Dimensioning and Tolerancing for Engineering Drawings”. Usu
22、ally the proper measurement plane is obvious. Where the plane of out-of-roundness meas- urement is not obvious or must be controlled relative to a particular part feature, such as parallel to a shoulder surface or perpendicular to a specific axis, this specification must be added to the roundness sy
23、mbol. 3.2.2 Symbol Interpretation 3.2.2.1 Minimum Roundness Symbol. The spec- ification in Fig. 1 means the out-of-roundness shall not exceed 0.000025 inch. Since complete measure- ment conditions for a stylus type instrument4 have not been specified here, it is understood that where such an instrum
24、ent is used, the following shall be in effect: Method of Assessment-Minimum Radial Sepa- Instrument Response-50 Cycles per Revolution Stylus Tip Radius-0.01 in. (see par. 5.3) ration (see par. 2.9) (see par. 5.2) .OOO 025 I FIG. 1 MINIMUM ROUNDNESS SYMBOL 3.2.2.2 Complete Roundness Symbol. This symb
25、ol shown in Fig. 2 is used when measured condi- tions must be specified. 2 AMERICAN NATIONAL STANDARD MEASUREMENT OF OUT-OF-ROUNDNESS THIS SURFACE SHALL BE ROUND WITHIN 0.900050 IN AS ASSESSED BY THE 1SC METHOD w; AND PSPONSE A 0.003 RADIUS STYLUS TIP. 10 I .000050 LSC I FIG. 2 COMPLETE ROUNDNESS SY
26、MBOL AND INTERPRETATION 4 SELECTION OF MEASUREMENT POSITIONS 4.1 Angular Position of Profile Plane The position of the measurement plane shall be determined by the related datum feature, e.g., per- pendicular to a cylindrical surface or datum axis, or parallel with an end face or shoulder. An exampl
27、e of a properly and improperly positioned measurement plane is shown in Fig. 3. ANSI 889.3.1-1972 FIG. 4 AXIAL POSITIONS OF MEASUREMENT PLANES 4.2 Number 5ind Axial Location of Profile Planes The axial locations and the minimum number of out-of-roundness measurements that are required to define the
28、surface of a three-dimensional body cannot be specified in this standard. Sufficient measurements should be taken to ensure that the measured profiles are typical. I 4.3 Location of Part Center-Relation to Instrument Axis FIG. 3 ANGULAR POSITION OF MEASUREMENT PLANE Any eccentricity between :he cent
29、er of the part, as determined from the measured profile centcr of See Appendix D2.1 paragraph 2.7, and the rotational axis of the measuring instrument causes a distorted representation of the profile. This distortion increases with increasing ec- 3 AMERICAN NATIONAL STANDARD MEASUREMENT OF OUT-OF-RO
30、UNDNESS centricity. To reduce this distortion to a negligible amount and to properly center incomplete circular surfaces, the Center for Out-of-Roundness Measure- ment, as determined by paragraph 2.8 or 2.9, shall coincide with the rotational center of the polar chart within 0.1 inch plus 5 percent
31、of the radial distance between the innermost profile point and the chart rotational center. 5 INSTRUMENTS 5.1 General Out-of-roundness as defined in this standard is usually measured by methods involving a stylus in contact with the part surface. Analog or digital tech- niques are used to reconstruc
32、t for graphical recording (usually on a polar chart) the magnified radial move- ments of the stylus, as either the stylus or the part is rotated around an accurately defined axis. This sec- tion of the standard is concerned only with this type of instrument. While this section deals with contacting
33、stylus instruments; other non-contacting sensors which produce similar radial deviation data are not excluded from this standard. 5.2 Cycles Per Revolution Response This term refers to the measurement characteristic of the instrumentation which limits the number of regularly spaced sine-wave shaped
34、undulations of the actual profile that will be correctly rerresented by the measured profile. For the purposes of this standard, the term Cycles Per Revolution response shall mean that number of cycles at which 70.7 percent of the amplitude data has been correctly transmitted through the instrument.
35、 The upper and lower response fre- quencies of the instrument shall correspond with the Cycles Per Revolution response values selected from the following: 0, 1.67, 5, 15, 50, 150. 500, 1500. If no response figures are specified, the 0-50 values shall be assumed. If only a single response figure is B
36、ased on a maximum allowable chart distortion of approxi- See Appendix C3 and D 1.1 for further discussion of Cycles See Appendix D1.Z. See Appendix D1.3. mately 0.01 in. due solely to profile eccentricity. Per Revolution Response. ANSI 889.3.1-1972 specified, it shall be the upper response value and
37、 the lower value shall be zero. 5.3 Stylus Radius Selection of the nominal stylus radius should be made with the part surface characteristics in mind3, and should be chosen from the series shown in Table 1. Table 1. Stylus Radius and Force Combinations Nominal Stylus Radius Max. Stylus Force - gms.
38、in. Steel or Harder Matl.* O.OOl* 0.5 0.003 2.0 0.01 0 5.0 0.030 10.0 0.1 00 20.0 Note: A stylus radius of 0.010 in. shall be assumed if no radius is specified. * For materials softer than Rockwell “C” hardness of 20, the stylus force should be selected to prevent objectionable plastic deformation o
39、f the surface, yet should be high enough to reduce stylus bounce and produce repeatable traces. * Fine su:face irregularities, e.g. surface roughness, may be penetrated by a stylus of this or smaller radius, which may confuse and render difficult the interpretation of measured profiles as prescribed
40、 in this standard. 5.4 Tolerances on Stylus Radii The actual range of stylus spherical radii shall be within 50 percent to 200 percent of the nominal value listed in Table 1. 5.5 Stylus Static Force The appropriate stylus force4 to maintain adequate contact with the part surface will depend upon the
41、 hardness, the flexibility, and the maximum compres- sive strength of the part material, the rotational speed and mass of the stylus assembly (for rotating stylus instruments), and the stylus tip radius. To minimize surface damage from high compressive stresses yet maintain a high contact pressure f
42、or consistent meas- ured profiles, the maximurn stylus force for each nominal stylus radius shall be determined from Table 1. 4 AMERICAN NATIONAL STANDARD MEASUREMENT OF OUT-OF-ROUNDNESS ANSI 689.3.1-1972 APPENDIX A BASIC CONCEPT OF ROUNDNESS MEASUREMENT A1 OBJECTIVE OF THE MEASUREMENT The objective
43、 of roundness measurement is to evaluate fom1 errors of components as opposed to feature size. Whenever one or more surfaces of a cylinder, cone, or sphere are required to have round- ness of a high order, cross-sections of.the feature must be measured to assure that the profile falls within the req
44、uired form tolerance. Al. 1 Roundness Tolerance Ideally all tolerances should be functionally de- rived, whether they be of form, size, texture, or other parameter. The tolerance on roundness should not be implied by related feature tolerances, such as size or surface texture. A2 BASIC MEASUREMENT C
45、ONSIDERATIONS The measurement of roundness is difficult to per- form directly. It is usually necessary to measure and interpret a series of cross-sectional profiles assumed to be typical of the entire surface. These measured profiles are generally sufficiently accurate for func- tionai evaluation an
46、d control. See Appendix D1.2. See Appendix D 1.1. A3 REDUCTION OF ROUGHNESS EFFECTS Since the cross-section is of such importance, its selection must assure typicality. Also the measurement process should eliminate or minimize the effects of surface roughness, which occur in both the axial and circu
47、mferential planes. The effect of axial surface roughness should be reduced by the use of a sensor of relatively large effective area, e.g., a large radius stylus tip, either spherical or hatchet shaped. The circumferential roughness effect should be reduced by the proper use of a large area sensor a
48、nd a sufficiently low Cycles Per Revolution response value2. Unless surface roughness effects are reduced to a negligible amount, the roughness characteristics may cause a significant increase in the out-of-roundness value observed. A4 UNIFIED MEASUREMENT PROCEDURES Since out-of-roundness is determi
49、ned by indirect means, and the part or work piece is judged by some measured representation, the results can be affected by the selection of the cross-sections, the instrument data-gathering processes, recorded chart distortions, and differences in interpretation. If the conditions defined in this standard and its appendices are applied, these variables will be reduced to tolerable proportions. 5 AMERICAN NATIONAL STANDARD MEASUREMENT OF OUT-OF-ROUNDNESS APPENDIX B ANSI 889.3.1-1972 CAPABILITIES AND LIMITATIONS OF VARIOUS METHODS OF MEASUREMENT B1 MEASURE
