Machine tool and control method therefor

摘要

In cutting a high-accuracy thread, a control unit (CPU) uses a first position data calculation program to determine the moving positions of a workpiece and tool every predetermined rotational angle of a spindle rotating motor. The control unit stores the determined moving positions of the workpiece and tool in a first position data table memory, and outputs the determined moving positions as a workpiece position instruction signal and tool position instruction signal to a workpiece feed control circuit and tool feed control circuit every predetermined rotation. In cutting a low-accuracy thread, the control unit uses a second position data calculation program to determine the moving positions of the workpiece and tool every predetermined time interval. The control unit stores the determined moving positions of the workpiece and tool in a second position data table memory, and outputs the determined moving positions as a workpiece position instruction signal and tool position instruction signal to the workpiece feed control circuit and tool feed control circuit every predetermined time interval.