| 摘要 |
<p>PURPOSE:To facilitate sensing of breakage of a cutting-off, in an NC automatic lathe having a drive shaft solely devoted to process the back surface, by sensing revolutions of the spindle, after the cutting-off process is completed, from the rotation of said back face processing drive shaft, which rotates while gripping the foremost end of the work to be processed. CONSTITUTION:In this automatic lathe, a tool arranged on a tallet tool rest 5 performs intended machining to a rod, which is inserted in the spindle 2 and whose foremost end is gripped by a chuck 17, and when the whole processing is completed, a cutting-off tool T1 shall cut away the work W. At this time a drive shaft 19 for processing the back surface is advanced, an the foremost end of the work W is inserted in a collet chuck 22 and gripped firmly, and then the cutting-off operation is carried out. After this operation, the spindle 2 is stopped, while a drive shaft 9 is solely rotated slowly, and when the tool T1 is broken, the work W does not separate from the rod and the spindle rotates along with the drive shaft 19. The revolutions of this spindle 2 are sensed by an encoder 9 to judge if the tool T1 is broken.</p> |
