A cluster analysis applied to volumetric errors of five-axis machine tools obtained by probing an uncalibrated artefact

This paper presents a cluster approach to the analysis of volumetric error for five-axis machine tools. The probed artefact is uncalibrated so the analysed volumetric errors exclude isotropic scale errors. First, a simultaneous model based estimation of machine and artefact geometric parameters enhances the estimation of the artefact. Then, a point-to-point least squares adjustment is performed between the measured and the predicted ball centre clusters. Information about the volumetric impact of both the linear and rotary axes as separate groups is obtained by analysing the position measurement error of the artefact as a whole and of each ball individually. Simulation is conducted for the validation of the method supported by experiments.