Abstract
The use of machine tools for on-machine coordinate measurement on the workpiece is becoming commonplace. However, numerous errors can adversely affect the measurement accuracy. For instance, the inter-axis parameters are major contributors to the overall machine tool's inaccuracy hence estimation and compensation of such errors are prerequisite to fully exploit the machine measurement potential. This paper presents a scheme to assess the accuracy of coordinate measurement by probing a precision sphere mounted on the machine table and probed for different rotary axes indexations. The individual probing data, and not the computed sphere centre, are used for the assessment thus providing a richer data set. Machine readings are processed either directly, using the machine nominal model or using a compensated model. This provides a fast method to validate on-machine measurement before and after compensation.
