Patent ID: 6651019
Filing Date: 2003-11-18
Classification: B23Q,G05B

Abstract:
A method for calculating a correction value for thermal displacement occurring along an axis of a main spindle in a machine tool, the method comprising the steps of:measuring a temperature in the vicinity of the main spindle; estimating an amount of the thermal displacement on the basis of the measured temperature and a predetermined thermal displacement amount calculation expression; and calculating the correction value on the basis of the estimated thermal displacement amount, wherein, (1) when the main spindle has been continuously rotated without interruption after start-up thereof, the correction value is calculated on the basis of the estimated thermal displacement amount alone; and (2) when the rotation of the main spindle is restarted after interruption thereof, the correction value is calculated on the basis of the estimated thermal displacement amount and also an amount of displacement delay occurring due to the interruption, the amount of displacement delay being estimated as an actual displacement amount of the main spindle relative to the estimated thermal displacement amount.