US Patent No. 9,235,199

WARM-UP CONTROL DEVICE FOR MACHINE TOOL


Patent No. 9,235,199
Issue Date January 12, 2016 
Title Warm-up Control Device For Machine Tool
Inventorship Takaaki Fujii, Yamanashi (JP)
Assignee FANUC CORPORATION, Yamanashi (JP)

Claim of US Patent No. 9,235,199

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.