Patent ID: 9235199
Filing Date: 2016-01-12
CPC Classification: G05B

Claim Text:
1. 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 and a time at which the thermal displacement amount is calculated; 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 calls up, from the thermal displacement amount storage unit, the thermal displacement amount that is calculated every predetermined time period back to a time traced back by a previously set time period, after the end of the warm-up, calculates a difference between a maximum value and minimum value out of the called thermal displacement amounts, and compares the difference between the maximum value and the minimum value of the displacement amounts with a previously set permissible value to determine whether or not to restart the warm-up; and a warm-up restarting part that restarts the warm-up when the warm-up restart determination part determines to restart the warm-up.