WORKPIECE ABNORMAL CLAMPING DETECTING METHOD IN MACHINE TOOL AND MACHINE TOOL

PROBLEM TO BE SOLVED: To provide an abnormal clamping detecting method and a machine tool capable of precisely and easily detecting the abnormal clamping of a workpiece. SOLUTION: This workpiece abnormal clamping detecting method in a machine tool, which clamps both ends of a workpiece 27 by clamp mechanisms 23 and 24 of a pair of headstocks 19 and 29, synchronously rotates the main spindles 21 and 22 of the both headstocks by servomotors 33 and 33 and machines the workpiece while rotating it, is characterized in commanding a servomotor of one headstock alone to rotate at a micro angle α with the servomotors 33 and 34 of the both headstocks put on and, when a current or a torque generated in the servomotor of one or the other headstock is smaller than a prescribed value, determining it as the abnormal clamping. COPYRIGHT: (C)2008,JPO&INPIT