Evaluation of a telescopic simultaneous ballbar in a 3-axis machine tool using a reference equipment

Abstract

This paper outlines the evaluation methodology for a Telescopic Simultaneous Ballbar (TSB) developed for distance measurement using an interferometer as a reference equipment. The procedure is executed in a 3-axis machine tool, one of the final applications of the TSB that is machine tool volumetric verification. Two distinct evaluation techniques are devised, with the new virtual line approach enabling an assessment of the TSB's performance within an extended verification volume and requiring only a single alignment position for the interferometer. The measurement repeatability of the equipment is assessed and its measurement uncertainty is estimated in workshop conditions. The results reveal the flexibility of the TSB measurement process similar to that of a laser tracker and the degree of measurement accuracy, which shows values comparable to the interferometer. Consequently, the TSB could facilitate faster and more accurate machine tool verification and calibration compared to existing systems.