| 摘要 |
PURPOSE:To shorten the piercing time and to improve operability in passing through a piercing hole on a work by a laser beam by detecting the sudden change of frequency of a piercing sound generated on the inside of a laser beam nozzle by a sound sensor. CONSTITUTION:The sudden change of frequency generated at the time of passing through the piercing hole 31 by the laser beam LB on the work W positioned on a work table 11 is detected and a piercing hole passing through completion signal is outputted to an I/O unit 55. Further, the signal is transferred to a detection amplifier 53 and an ON signal is given to a laser beam oscillator 3 from an NC device 57 and in order to cut the work W by the laser beam LB, a microphone 49 for detecting the sound is provided on the inside of the laser beam nozzle 27 provided at the lower part of a machining head assembly body 13. The microphone 49 is connected to the detection amplifier 53 and the detection amplifier 53 and the laser beam oscillator 3 are connected by a signal cable 51 via the NC device 57, by which the change of frequency of the sound in the laser beam nozzle 27 can be detected regardless of material and thickness of the work W. |
