Machining, Measurement, and Control Laboratory

Calibration of location errors of rotary axes on five-axis machine tools by on-the-machine measurement using a touch-trigger probe
Soichi Ibaraki, Takeyuki Iritani, Tetsuya Matsushita

As a basis to improve the motion accuracy of five-axis machining centers, it is important to develop a methodology to calibrate location errors of rotary axes, one of the fundamental error sources in the five-axis kinematics, in an accurate, efficient, and automated manner. This paper proposes a scheme to calibrate location errors of rotary axes by on-the-machine measurement of a test piece by using a contact-type touch-trigger probe installed on the machine's spindle. Compared to conventional calibration schemes described in latest revision of ISO standards (ISO/DIS 10791-1:2012 and ISO/DIS 10791-6:2012), where a precision sphere and a linear displacement sensor or the ball bar are used, the proposed approach is more suitable to efficient and automated calibration procedure of location errors, without requiring an experienced operator to perform the tests. The uncertainty analysis of the calibration of location errors is also presented with a particular interest in the influence of error motions of linear axes. The experimental demonstration is presented.
Keywords: Five-axis machine tools; Rotary axis; Location errors; Touch-trigger probe; Error calibration.