| 摘要 |
PURPOSE:To improve the accuracy of processing, by using a laser unit to detect the difference between the feed of a rotary lead screw and an actual displacement to compensate a workpiece in the axial direction. CONSTITUTION:When a lead screw 1 is rotated by one round by a first motor M1, a sliding table 4 is moved rightward by a distance corresponding to the pitch of the lead screw. Laser rays are emitted from a laser unit 13 and reflected to the emission position by a reflector 14. The time of the transmission of the laser rays from the laser unit 13 to the reflector 14 and from the reflector back to the laser unit is measured to determine the distance. The rotational angle of the lead screw 1 is detected by a tachometer generator 2 and compared with a calculated theoretical value. If the compared quantities differ from each other, a servo-valve 10 is opened to cause a pressure difference between both the sides of a static-pressure thrust bearing 9 to move a main shaft 7 in the axial direction. |
