Method and apparatus for controlling numerically controlled machine tool

摘要

A method and an apparatus for controlling a numerically controlled machine tool, wherein the heat generation amount and the temperature of a drive unit including a servo amplifier 15b and a feed shaft motor 3 are computed by a drive unit heat generation amount computing unit 31 by simulation, and from the computed heat generation amount and the computed temperature, the total heat generation amount of the drive unit, the cutting feed heat generation amount, the cutting load heat generation amount, etc. are computed by a feed heat generation amount computing unit 39, so that the cutting feed rate override value of the numerically controlled machine tool 1 is computed by a cutting feed rate override computing unit 27 and effectuated by being output to a NC unit. Further, based on the temperature of the drive unit computed by a computing unit 31 or the temperature computed by a temperature data computing unit 47 or the temperature detected by a temperature detection sensor 49, etc., the proper values of the feed acceleration/deceleration time constants &tgr;r and &tgr;c are computed and output as a ratio with respect to the set and stored initial values &tgr;r0 and &tgr;C0 thereby to control the NC commanded rate. The overheating of the feed axis drive unit is prevented while at the same time improving the machining efficiency.