| 摘要 |
The present invention is to provide a machine tool in which appropriate warm-up operation can be performed. Unnecessary warm-up operation before machining is not carried out and damage of bearings caused by the warm-up operation is prevented. A controlling unit 7 stores data of a supply amount of lubricant to bearings 4 and a rotation speed of a main spindle 2 in a memory unit 22 as time-series data. When rotation of the main spindle 2 is started, the time-series data stored in the memory unit 22 is used to calculate an amount of remaining lubricant in the bearings 4 and determination of necessity of warm-up operation is made based upon the stored data. A rotation speed at a start-up time of the main spindle is controlled according to the determination result.
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