Machining, Measurement, and Control Laboratory

The Influence of Inertia Force and Viscous Friction on Contouring Errors in Circular Interpolation
Minoru HAMAMURA (Toshiba Machine Co., Ltd.) Jun FUJITA (Toshiba Machine Co., Ltd.) Yoshiaki KAKINO (Kyoto University) Atsushi MATSUBARA (Kyoto University)  

This paper considers contouring errors in circular interpolation on NC machine tools. It is shown by using analytical models that the difference of the following three properties between two axes causes an elliptical error on circular interpolation: the driven mass, the stiffness of feed drive system, and the viscous damping coefficient of linear guide. Especially, the inertia force causes a different error on each axis, and the viscous friction slopes the elliptical contouring error profiles. Several motion tests are conducted by using a horizontal machining center. Measured contouring error profiles coincide well with simulated results.

Key words: NC machine tools, feed drive system, circular interpolation, contouring errors, viscous friction