Author(s)

M.G. Cox, M.P. Dainton, A.B. Forbes & P.M. Harris

Abstract

Validation of CMM form and tolerance assessment software M.G. Cox, M.P. Dainton, A.B. Forbes & P.M. Harris Certfre /or Ma^ema^cs oW National Physical Laboratory, UK Abstract While the verification of the performance of coordinate measuring machines (CMMs) is self-evidently important, the point coordinates they provide are usually the input to form and tolerance assessment software that calculate associated geometric features, such as a best fit cylinder to the data. For the measurement result to be reliable, it is also necessary to ensure that the calculations performed by this software are fit for purpose. The forthcoming standard ISO 10360-6:2001 [1] specifies the procedure by which Gaussian (least-squares) form assessment software should be tested. Many tolerance assessment problems relate to Chebyshev (minimum- zone) fitting criteria in which the maximum error is minimized. These criteria lead to nonlinearly constrained optimization problems that are dif- ficult to solve rel

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