Latest Progress in Performance and Understanding of Laser Welding

Abstract

Abstract This paper describes a variety of fundamental research results of laser welding which the authors have recently performed. The behavior and characteristics of a laser-induced plume were elucidated. Especially, in remote welding with a fiber laser, the effect of a tall plume leading to shallow weld was interpreted by considering the interaction of an incident laser beam against the zone of a low refractive index from the Mickelson interferometer results. The laser absorption in the plate was higher in the case of a smaller focused beam of fiber laser, lower welding speed and higher power, and the reason was interpreted by considering the size and location of a keyhole inlet and a beam spot. High power tandem laser beams could produce deep penetration, and laser welding in vacuum was developed for production of deeply penetrated welds. Laser direct joining was also developed for joining of metal to plastic or CFRP.