MONITORING DEVICE FOR LASER BEAM WELDING

摘要

PROBLEM TO BE SOLVED: To monitor a welding state in process in a laser beam welding system, especially in a laser beam welding intended for a thick plate. SOLUTION: This device is provided with a light source device 11 which generates monitoring light having a wavelength different from a welding laser beam, optical systems 23, 27, 19 which guide monitoring light so as to irradiate a part 15 irradiated with a laser welding laser, a band pass filter 33 which penetrates monitoring light reflected from the irradiated part and a light receiving element 31 which detects light via the band pass filter. A welding state is inferred by detecting reflected light of monitoring light which reflects the behavior of a keyhole 15.