Reduction of the influence on machining surface caused by tool non-repeatable run-out of rolling bearing spindle for machine tools (Improvement of machining surface quality with an excitation system)

Abstract

In recent years, the demands for mirror finishing by cutting have increased, because the surface quality requirement in die and mold has become severer. In order to realize mirror surface finish by cutting, it is necessary to reduce the influence of tool non-repeatable run-out (NRRO) on machining surface. Rolling bearings used in a spindle for machine tools may cause NRRO of cutting tool due to rolling element revolution. In order to reduce the influence of NRRO on machining surface, an excitation system which can generate counter excitation force has been proposed in this study. The gradual change of multiple peaks of NRRO in frequency domain was observed. Excitation experiment results confirmed that the proposed excitation system can reduce NRRO from the relative displacement between the table and the tool. Furthermore, actual cutting results confirmed a correlation between NRRO reduction of the relative displacement and NRRO reduction on the machined surface.