Patent ID: 7997385

Claim:
A machine tool comprising: a main spindle rotatably supported via a bearing into which lubricant is supplied; and a controlling unit which controls rotation operation of the main spindle and supply operation of lubricant to the bearing, wherein the controlling unit stores data of an amount of lubricant to supply to the bearing during operation and a rotation speed of the main spindle in a storing unit as time-series data, and when the main spindle is started, the time-series data of the previous operation stored in the storing means is used to calculate an amount of remaining lubricant in the bearing, to determine the necessity of a warm-up operation based upon the amount of remaining lubricant in the bearing at the time of starting, and if the amount of remaining lubricant exceeds a threshold value and the controlling unit determines that a warm-up operation is required, the controlling unit determines a rotation speed and a rotation time for the warm-up operation and performs the warm-up operation according to the predetermined rotation speed and rotation time.