Stable conduction mode welding of conventional high-reflectivity metals with 2000 W blue laser

Abstract

High-reflectivity metals, e.g., copper and aluminum, have been widely applied for various industrial products such as power battery, electrical machinery, et al. However, owing to the low absorption rate of copper and aluminum to the conventional infrared laser (900–1080 nm), the keyhole welding mode is required, which is extremely unstable. A blue laser (450 nm) can improve the absorption rate of copper and aluminum evidently, which has potential to weld copper and aluminum at the conduction mode. This work studies the bead-on-plate welding of copper and aluminum by the blue laser. At a blue laser power of 1950 W, the welding depths of copper and aluminum can acquire 1.20 and 1.83 mm. Then, this work exhibits the molten pool characteristics of copper and aluminum in high-power blue laser welding, and builds a relationship between the molten pool characteristics and the welding bead qualities. The unstable boundary of the middle gray-scale region in welding of copper and the ripple phenomenon in welding of aluminum indicate a small depth and rough appearance. This work validates that the 2000 W high-power blue laser can weld conventional high-reflectivity metals (e.g., copper and aluminum) at the conduction mode without spatters, while the keyhole mode is required for welding with the infrared laser.