To change the depth of cut according to the curve of the front surface by continuously controlling the depth of cut of a tool as the function of the position in the cutting direction of a work in relation to the tool on the basis of the information related to the shape of the work front surface.
When a movable part 11A is moved in the retreating direction, the displacement in the X-axis direction or the coordinate of a work 20 is measured by an X-axis position measuring device 41, and simultaneously, the shape of the front surface of the work 20 is detected by a shape detecting device 45. The curved line indicating the shape of the front surface of the work 20 is found from the X-coordinate value supplied from the X-axis position measuring device 41 and the Y-coordinate value supplied from the shape detecting device 45. A jogging tool table 33 is continuously displaced in the Y-axis direction by a piezoelectric element 34 on the basis of the front surface shape of the work 20, and the depth of cut of a tool 31 is continuously changed.
HAGA MOTOHISA
BIZEN NAOTO
