| 摘要 |
<p>PROBLEM TO BE SOLVED: To judge during laser beam welding that welding is not suitably execut ed by judging it as a defect when a frequency distribution based on the mea sured result of plasma light beam in the case of welding two or more works is the same as a previously stored frequency distribution in the quality inspecting method of laser beam welding. SOLUTION: A differential amplifier 12 for taking out only a luminous signal in the inner part of a keyhole from signals from sensors 10a and 10b is provided with in order to measure the luminous intensity of plasma light beam. A signal from the differential amplifier 12 passes through a band path filter 13 and inputted into a personal computer 11 via a converter 14. The frequency distribution being a reference for judging the quality of welding is previously stored in the personal computer 11, and the quality at the time of welding is judged by comparing with the measured result. A laser beam light 2 required for welding is irradiated from the upper side of a work 1a. Sensor 10a and 10b are provided in the position where an elevation angle from the surface of the work 1a in the laser irradiating side is different.</p> |
