| 摘要 |
PURPOSE:To prevent the occurrence of the defective machining by providing a photosensor to detect the emission at the focusing position of a machining lens when a laser beam irradiates an objected to be a worked. CONSTITUTION:In the case of irradiating the laser beam 2, when the photosensor 20 detects the light emission in the vicinity of the focusing position 9 of the machining lens 5, a detector 30 devices that an air brake phenomenon takes place and outputs a defective machining detection signal 31 when the output from the photosensor 20 becomes more than a level. In this way, the defective machining can be prevented. |
