ASME B89.4.22-2004

Methods for Performance Evaluation of Articulated Arm Coordinate Measuring Machines

AN A MERICAN NA TIONAL S T AND ARD

ASME B89.4.22-2004

ASME B89.4.22-2004

Methods for Performance Evaluation of Articulated Arm Coordinate Measuring Machines

AN AMERICAN NATIONAL STANDARD

Three Park Avenue • New York, NY 10016

Date of Issuance: August 12, 2005

This Standard will be revised when the Society approves the issuance of a new edition. There will be no addenda issued to this edition.

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The American Society of Mechanical Engineers Three Park Avenue, New York, NY 10016-5990

Copyright © 2005 by

THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS

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CONTENTS

Foreword iv

Committee Roster v

Correspondence With the B89 Committee vi

Introduction 1

1. Scope 1

2. Definitions 1

3. Environmental Specifications 5

4. Environmental Tests 8

5. Machine Performance 9

6. Test Equipment 17

   Figures

   1. AACMM Classification Form 2

   2. Environmental Specification Form 3

   3. Performance Specification Form 4

   4. Typical Machine of the 2-1-2 Configuration, With a-b-d-e-f deg Rotation 5

   5. Typical Machine of the 2-2-2 Configuration, With a-b-c-d-e-f deg Rotation 5

   6. Typical Machine of the 2-1-3 Configuration, With a-b-d-e-f-g deg Rotation 5

   7. Typical Machine of the 2-2-3 Configuration, With a-b-c-d-e-f-g deg Rotation 5

   8. AACMM Mounted Vertically for Evaluation 7

   9. AACMM Mounted Horizontally for Use 7

   10. Mounting Stiffness Test Setup 9

   11. Three Default Locations of the Mounted Seat During the Single-Point

       Articulation Performance Test 11

   12. Isometric View of Default Articulations 11

   13. Default Five-Point Probe Pattern 12

   14. Octant Numbering Scheme 14

   15. Recommended Ball Bar Locations 15

   16. Volumetric Performance Test Results 17

Tables

1. Diameter Deviations 10

2. Single-Point Articulation Performance Test 13

3. Recommended Artifact Positions 16

4. Volumetric Performance Test Results 16

Nonmandatory Appendices

FOREWORD

The ambiguity of articulated arm coordinate measuring machines (AACMM) specifications makes comparative evaluations of performance characteristics very difficult. Because of this and the increasing use of this class of measurement equipment, the ASME Standards Committee B89 elected to establish a USA industry standard applicable to these machines. At the October 1994 meeting, Project Team B89.4.22 was established to develop the Standard.

As far as possible, this Standard parallels ASME B89.4.1b-2001 for “conventional” coordinate measuring machines. An attempt has also been made to make the Standard compatible with ex- isting and emerging international standards.

This Standard addresses the performance evaluation of AACMM by supplying definitions and test procedures. These procedures should enable users to determine if an AACMM is appropri- ate for their specific requirements. It should also provide accurate comparison of machines from different suppliers and provide a determination of whether an AACMM meets contractual re- quirements without negotiations after the machine has been purchased.

The intent of this Standard is to specify the simplest methods that can be used for reasonable performance evaluation. It is recognized that a more complex evaluation may be appropriate for special applications. These methods, however, must be specified in adequate detail in the AACMM specification.

This Standard was approved by the American National Standards Institute on August 9, 2004.

iv

ASME B89 STANDARDS COMMITTEE

Dimensional Metrology

(The following is the roster of the Committee at the time of approval of this Standard.)

OFFICERS

B. Parry, Chair

D. Beutel, Vice Chair

M. Lo, Secretary

COMMITTEE PERSONNEL

D. Beutel, Caterpillar, Inc.

J. B. Bryan, Bryan Associates

T. Carpenter, USAF, Newark AF Base

T. Charlton, Jr., Charlton Associ8s

D. Christy, Mahr Federal

G. Hetland, International Institute of Geometric Dimensioning and Tolerancing

R. J. Hocken, University of North Carolina

M. Leibers, Professional Instruments Co.

M. Lo, The American Society of Mechanical Engineers

B. Parry, The Boeing Co.

S. D. Phillips, National Institute of Standards and Technology

J. Salsbury, Mitutoyo America Inc.

D. Swyt, National Institute of Standards and Technology

B. R. Taylor, Renishaw PLC

SUBCOMMITTEE 4 — COORDINATE MEASURING TECHNOLOGY

S. D. Phillips, Chair, National Institute of Standards and Technology

D. Beutel, Caterpillar, Inc.

T. Carpenter, U.S. Air Force, Newark AF Base

T. Charlton, Jr., Charlton Associ8s

T. D. Doiron, National Institute of Standards and Technology

J. L. Henry, Sheffield Measurement

R. B. Hook, Metcon

B. Parry, The Boeing Co.

R. C. Veale, National Institute of Standards and Technology

D. Wright, Renishaw PLC

PERSONNEL OF WORKING GROUP B89.4.22 — ARTICULATED ARM COORDINATE MEASURING MACHINES

B. Parry, Chair, The Boeing Co.

G. Caskey, University of North Carolina at Charlotte

S. Ilmrud, Romer CimCore Inc.

S. Raab, FARO Technologies

D. Wright, Renishaw PLC

SPECIAL ACKNOWLEDGEMENT

While not a member of the Project Team when the document was approved, we would like to acknowledge the work performed and significant contributions made by Michael O’Laughlin, while an employee of Romer Inc. Mike was the Secretary since the inception of the Project Team and, thanks to his diligent minutes, kept the remainder of us on track.

v

CORRESPONDENCE WITH THE B89 COMMITTEE

General. ASME Standards are developed and maintained with the intent to represent the con- sensus of concerned interests. As such, users of this Standard may interact with the Committee by requesting interpretations, proposing revisions, and attending Committee meetings. Corre- spondence should be addressed to:

Secretary, B89 Standards Committee

The American Society of Mechanical Engineers Three Park Avenue

New York, NY 10016-5990

Proposing Revisions. Revisions are made periodically to the Standard to incorporate changes that appear necessary or desirable, as demonstrated by the experience gained from the applica- tion of the Standard. Approved revisions 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 de- scription of the reasons for the proposal, including any pertinent documentation.

Interpretations. Upon request, the B89 Committee will render an interpretation of any re- quirement of the Standard. Interpretations can only be rendered in response to a written request sent to the Secretary of the B89 Standards Committee.

The request for interpretation should be clear and unambiguous. It is further recommended that the inquirer submit his/her request in the following format:

Subject: Cite the applicable paragraph number(s) and provide a concise description. Edition: Cite the applicable edition of the Standard for which the interpretation is be-

ing requested.

Question: Phrase the question as a request for an interpretation of a specific require- ment suitable for general understanding and use, not as a request for an ap- proval of a proprietary design or situation.

Requests that are not in this format may be rewritten in the appropriate format by the Commit- tee prior to being answered, which may inadvertently change the intent of the original request.

ASME procedures provide for reconsideration of any interpretation when or if additional in- formation that might affect an interpretation is available. Further, persons aggrieved by an in- terpretation may appeal to the cognizant ASME committee or subcommittee. ASME does not “ap- prove,” “certify,” “rate,” or “endorse” any item, construction, proprietary device, or activity.

Attending Committee Meetings. The B89 Standards Committee regularly holds meetings that are open to the public. Persons wishing to attend any meeting should contact the Secretary of the B89 Standards Committee.

vi

ASME B89.4.22-2004

METHODS FOR PERFORMANCE EVALUATION OF ARTICULATED ARM COORDINATE MEASURING MACHINES

INTRODUCTION

The primary purpose of this Standard is to clarify the performance evaluation of articulated arm coordinate measuring machines (AACMMs). A secondary purpose is to facilitate performance comparisons between ma- chines. Definitions, environmental requirements, and test methods are specified. This Standard defines the test methods capable of yielding adequate results for the ma- jority of articulated arm coordinate measuring machines and is not intended to replace more complete tests that may be required for special applications.

1. SCOPE

   The scope of this Standard pertains to the perform- ance evaluation of articulated arm coordinate measur- ing machines. While any number of rotational joints can be evaluated, the Standard focuses on the more com- mon configurations commercially available today and is limited to seven joints. The Standard addresses purely manual machines, so no motorized axes are addressed in the current document. While the application of this class of measuring machine continues to grow, at this point in time only contact probes are considered and op- tical noncontact probes are specifically excluded.

   This Standard establishes requirements and methods for specifying and testing the performance of AACMMs. In addition to clarifying the performance evaluation of AACMMs, this Standard seeks to facilitate performance comparisons among machines by unifying terminology, general machine classification, the treatment of envi- ronmental effects, and data analysis. This Standard at- tempts to define the simplest testing methods capable of yielding adequate results for most AACMMs and it is not intended to replace more complete tests that may be suitable for special applications.

   This Standard provides definitions of terms applica- ble to AACMMs. These definitions are separated into two parts. The first part is a glossary covering technical terms used throughout this and other ASME Standards. The second part defines a number of common machine classifications.

   The actual specification is subdivided into three sections: general machine classification, machine envi- ronmental requirements, and machine performance. Machine classification includes machine type, measure-

   ment ranges, and rotary axis encoder resolution. Envi- ronmental specification includes thermal response, elec- trical requirements, and vibration sensitivity. Machine performance specification includes effective diameter test, single-point articulation performance, and volu- metric performance tests.

   Within this Standard, performance values are reported as the maximum deviation, the range, and the standard deviation. This is done to bring the Standard more into line with existing national and international standards.

   In order to clarify the use of this Standard, a short guide on how to use it is included as Appendix A.

   Productivity is an important consideration in the se- lection of an articulated arm coordinate measuring ma- chine. There are numerous factors that affect the rela- tive productivity of measuring systems, which include variables attributable to both the measurement system and the workpiece. This Standard does not address methods to specify and evaluate productivity. Produc- tivity should be evaluated with respect to the expected use of the system, including such aspects as software, ergonomics, and the frequency of calibration.

   
   

   1. Contents and Specification Forms

      Any specification described as complying with this Stan- dard shall include, as a minimum, the following items:

      1. ) a machine classification form (see Fig. 1). If no classification is applicable, the actual configuration shall be described in equivalent detail.

      2. an environmental specification form (see Fig. 2).

      3. ) a performance specification form (see Fig. 3).

         
         

   2. Alternatives

      This Standard allows parts of the environmental test section to be deferred or bypassed and only the per- formance tests to be carried out. This alternative is ac- ceptable only if it is agreeable to both the user and the supplier, and if deferred as specified.

      
      

2. DEFINITIONS

   1. Glossary

2.1.1 Terms. This glossary contains brief definitions of the majority of technical terms used in this Standard. Some of the definitions listed are used in the non-

1