Influence of Laser-Induced Plume on Penetration in Laser Welding

Abstract

The influence of laser-induced plume on penetration is discussed in remote laser welding. Melt-runs accompanying plumes of various lengths were carried out in order to investigate the influence of plume on penetration using 4.5 kW YAG laser and air knife. Penetration depth obviously reduced on the conditions with long plume. It is considered that the decrease of penetration depth comes from attenuation of laser power in plume, through the decrease in weld metal cross-sectional area. Attenuation of laser power was estimated about 7% and focus shift was estimated to be about 0.7 mm on the experimental condition with plume of 90 mm length, compared with the condition with plume of 11 mm length.