| 摘要 |
PURPOSE:To prevent the collision of a top end of nozzle and an object to be worked by maintaining the present distance within a definite time when an electrostatic capacity over than the standard value is detected with a height sensor. CONSTITUTION:A nozzle top end 5C of a torch part 5 of a laser beam machine 1, that is, a height sensor nozzle part 9 controls by changing an electrostatic capacity value generated due to the distance with the object to be worked 8 into a voltage value with a signal treatment circuit 15. When a plasma, etc., is generated during working with laser beam, in the electrostatic capacity obtained with the central electrode 9b of a torch part 5, if its value is rapidly detected over the standard range value, the output of the present value hold circuit 23 is supplied to the Z axis servo motor 6 with a delay timer 21 within the prescribed time. Therefore, during the prescribed time that the plasma is to be finished, the distance of the object to be worked 8 and the nozzle top end 5C can be kept in the present state. |
