Control device for machine tools and machine tool control method

A control device for machine tools which controls a machine tool having a spindle that causes a cutting tool and a workpiece to relatively rotate, and a feed axis which causes the cutting tool and the workpiece to relatively move, and cuts the workpiece by way of the cutting tool by causing the spindle and the feed axis to cooperatively act, the control device comprising:

• a feed command calculation unit which calculates a feed command for causing the feed axis to relatively move in relation to the workpiece;
• an oscillation phase calculation unit which calculates an oscillation phase that is a phase of oscillation to cause the feed axis to reciprocally move based on a rotation number of the spindle;
• an oscillation phase compensation unit which compensates the oscillation phase;
• an oscillation amplitude calculation unit which calculates an oscillation amplitude that is an amplitude of oscillation causing the feed axis to reciprocally move based on the feed command;
• an oscillation command calculation unit which calculates an oscillation command causing the feed axis to reciprocally move, based on the oscillation amplitude and the oscillation phase after compensation by the oscillation phase compensation unit;
• and
• a command synthesizing unit which calculates a synthetic command for driving the feed axis by superimposing the feed command and the oscillation command.