METHOD FOR HEAT DISPLACEMENT CORRECTION IN MACHINE TOOL AND HEAT DISPLACEMENT CORRECTION DEVICE

摘要

Using an unsteady heat conduction equation, the CPU of the disclosed machine tool computes the temperature distribution of a plurality of intervals of a ball screw shaft (81), and computes the magnitude of thermal displacement of each interval from said temperature distribution. The heat conduction matrix of the unsteady heat conduction equation includes a first heat conduction matrix that reflects the shape and material of the ball screw shaft (81), a second heat conduction matrix that reflects the structure of the ball screw mechanism, and a heat dissipation function. The heat dissipation function is set to the characteristic of heat dissipation increasing in response to an increase in rotational frequency of a servo motor. Therefore, the CPU can correct for error caused by thermal displacement with high precision on the basis of the magnitude of thermal displacement taking into account the amount of heat dissipation from the ball screw shaft (81).