摘要 |
The present invention includes a radial force detection mechanism for detecting a radial force generated by cutting operation of a cutting tool by use of an ultrasonic vibrator, a depth-of-cut feed mechanism for moving the cutting tool in the depth-of-cut direction, and a vertical feed mechanism for controlling the vertical position of the cutting tool, combined with correction of its movement in the depth-of-cut direction by the depth-of-cut feed mechanism, so as to bring it to the position where a radial force detection signal detected by the radial force detection mechanism becomes zero. By moving the cutting tool in the vertical direction by use of the vertical feed mechanism so that the radial force detection signal may become zero, no radial force is applied to the cutting tool. |