Investigation of Surface Quality in High Speed Welding of Aluminum Using Adjustable Ringmode Fiber Laser

Abstract

Sheet metals joint technology is highly required in many manufacturing industries where aluminum finds great application. Laser welding of aluminum has difficulties due to its low melting point, high thermal conductivity and low absorptivity. Upon reaching the melting point, the absorptivity increases with increasing temperature. In deep penetration welding, a lot of spatter arise hence deterioration of surface quality, while good surface quality is an essential factor to improve component functionality. In order to achieve deep penetration with stable welding phenomenon and ensure good surface quality, at a high welding speed, adjustable ring-mode fiber laser has been employed, since it offers high power with a dynamic adjustable beam profile consisting of a center part and a ringpart. Pure-ring-mode irradiation using ring power only and dual-mode irradiation using both center power and ring power, were investigated through experiments and numerical simulations. Dual-mode irradiation made it possible to stabilize the welding process. The center power helps to achieve sufficient deep penetration, while ring power ensures good temperature distribution.