ASME B89.4.22

Description / Abstract: The scope of this Standard pertains to the performance evaluation of articulated arm coordinate measuring machines. While any number of rotational joints can be evaluated, the Standard focuses on the more common 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 optical 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 environmental effects, and data analysis. This Standard attempts 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 applicable 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 environmental requirements, and machine performance. Machine classification includes machine type, measure-ment ranges, and rotary axis encoder resolution. Environmental specification includes thermal response, electrical requirements, and vibration sensitivity. Machine performance specification includes effective diameter test, single-point articulation performance, and volumetric 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 selection of an articulated arm coordinate measuring machine. There are numerous factors that affect the relative 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. Productivity should be evaluated with respect to the expected use of the system, including such aspects as software, ergonomics, and the frequency of calibration.