CMM test

A new testing procedure just published by the American Society of Mechanical Engineers (ASME) represents the final step in a decade-long effort led by the National Institute of Standards and Technology (NIST) to unite the US with the rest of the world in evaluating the performance of coordinate measuring machines (CMMs).

CMMs, which make precision measurements of the dimensions of objects, are critical in industries such as aerospace, automobile and heavy equipment manufacturing to ensure that parts match blueprints, and for performing reverse engineering and managing process control.

The US has been the only major country with its own national standard for CMM performance evaluation because US standards developers were concerned that the current version of international standard, ISO 10360-2, left major error sources unevaluated and contained ambiguities in the interpretation of the performance specifications.

For a decade the US team on the International Standards Organization CMM standard committee, led by NIST, worked to revise the international standard to correct these deficiencies and to develop a US version that also added tutorials and optional tests to address concerns specific to the US.

The new US document has now been published by the ASME as B89.4.10360.2, while its ISO counterpart is currently out for final approval by the international standards community.

ASME B89.4.10360.2-2008 Acceptance Test and Reverification Test for Coordinate Measuring Machines (CMMs) Part 2: CMMs Used for Measuring Linear Dimensions may be obtained from ASME at http://catalog.asme.org/home.cfm?SEARCH=B89.4.10360.2