Soichi Ibaraki, Kyoto University

The R-test is an instrument to measure three-dimensional displacement of a precision sphere, attached to a machine spindle, relative to a work table by using three displacement sensors. Its application to error calibration for five-axis machine tools has been studied. This paper presents a software to analyze measured R-test trajectories for error diagnosis and numerical compensation of rotary axes location errors and error motions. The developed software first graphically presents measured R-test trajectories to help a user's intuitive understanding of error motions of rotary axes. It also gives numerical parameterization of rotary axes geometric error parameters, as well as their compensation table to be implemented in some latest commercial CNC systems. Experimental demonstration of its application to a five-axis machine tool with a universal head (two rotary axes in the spindle side) is presented. The effectiveness of numerical compensation is studied.

Keywords: metrology, R-test, five-axis machine tools, calibration, error motion, geometric error