Patent ID: 7266903

Claim:
A method for correcting thermal displacement of a workpiece at a cutting edge position using a feed spindle in estimating an amount of thermal displacement based on a detected temperature obtained by detecting the temperature of each component of a machine tool and the coordinate data of the cutting edge position, the method comprising the steps of: presetting the coordinate data of a fixed position of the workpiece on a table; finding an amount of displacement of the fixed position of the workpiece at a current cutting edge position based on the detected temperature, the coordinate data of the cutting edge position, and the coordinate data of the fixed position of the workpiece; computing the difference in the coordinate data between the fixed position of the workpiece and the cutting edge position; finding an amount of displacement of the workpiece between its fixed position and the cutting edge position based on the detected temperature and the difference in the coordinate data between the fixed position of the workpiece and the cutting edge position, and computing a sum of each amount of displacement to define an estimated value and correcting thermal displacement using an NC unit based on the estimated value.