Warm-up control device for machine tool

A warm-up control device for a machine tool, which performs, before machining a workpiece, a warm-up by driving a main shaft rotary drive part for rotating a main shaft of the machine tool and axes drive parts for relatively driving a workpiece and a tool,

• the warm-up control device comprising:
• a thermal displacement amount calculation part that obtains a thermal displacement amount that results from heat generated or released upon starting or ending the warm-up of the machine tool and changes with time;
• a thermal displacement amount storage unit that stores the thermal displacement amount that is calculated every predetermined time period by the thermal displacement amount calculation part;
• a warm-up end determination part that determines whether to end the warm-up based on the thermal displacement amount;
• a warm-up ending part that ends the warm-up when the warm-up end determination part determines to end the warm-up;
• a warm-up restart determination part that determines whether to restart the warm-up after the end of the warm-up, based on the thermal displacement amount;
• and
• a warm-up restarting part that restarts the warm-up when the warm-up restart determination part determines to restart the warm-up.