Assessing thermally induced errors of machine tools by 3D length measurements

A new measurement technique is proposed for the assessment of thermally induced errors of machine tools. The basic idea is to measure changes of length by a telescopic double ball bar (TDEB) at multiple locations in the machine's workspace while the machine is thermally excited. In addition thermal machine error models are verified and optimised by comparing measured and predicted TDEB length deviations. Validation measurements reveal that more than 60 % of the thermally induced errors can be described by the thermal machine error model proposed at any time and at any position in the machine's workspace