Control device for machine tool

A control device for a machine tool that performs machining while oscillating a tool and a workpiece relative to each other, the control device comprising:

• an oscillation amplitude calculation unit that calculates an oscillation amplitude based on an oscillation condition for oscillating the workpiece and the tool relative to each other and a feed speed of the tool;
• a minimum value setting unit that sets a minimum value of the oscillation amplitude;
• a comparison unit that compares a calculated value of the oscillation amplitude calculated by the oscillation amplitude calculation unit with the minimum value of the oscillation amplitude set by the minimum value setting unit;
• an oscillation command generation unit that generates an oscillation command based on a value of the oscillation amplitude obtained from a comparison result by the comparison unit, and the oscillation condition;
• and
• a position-speed control unit that oscillates the workpiece and the tool relative to each other based on a superimposition command obtained by superimposing the oscillation command on a position command.