| 摘要 |
PURPOSE:To obtain a laser beam machining device having a high reliability, which can detect immediately a breakage of a condensing lens, by providing a gas detector for detecting a machining assist gas, on a laser beam incident side of the condensing lens. CONSTITUTION:When a crack is generated in a lens 3 in the course of a laser beam machining, and a through-part 12 is generated in a laser beam incident side 11 of the lens 3 and a nozzle hollow part 9, an inflow 6 machining assist gas 15 passes through the through-part 12, and flows into the incident side 11. The inflow gas 15 is detected by a machining assist gas detector 10. In this case, a gas detecting signal 19 from a laser beam machining device 18 is inputted to a gas detecting signal processor 20, a signal 21 for stopping a laser beam 18 emitted from a laser oscillator 16 is sent, and also a signal 22 for stopping the machining is sent to the device 17. At the same time, an alarm signal 24 is outputted to a lens abnormality alarm device 23, a breakage of the lens 3 can be informed automatically, the lens 3 is replaced immediately, and the working mistake can be prevented. |
