Influence of flow rate and gas type with a novel nozzle capable of simultaneously gas flow and suction on weld quality in laser welding

Abstract

Laser welding has been actively used in automotive manufacturing and other fields because of its non-contact and easy operation. In particular, the demand for high-quality welding of copper and aluminum is increasing due to the growing popularity of electric vehicles. However, conventional laser welding has led to problems such as spatter and unstable weld beads. Assist gas is one solution to improve welding efficiency and stabilize weld quality. In this study, two new nozzles for laser head scanning and Galvano scanning were developed that can simultaneously flow and suction gas to the laser welding area. In butt welding of steel using an infrared laser, fume removal from the laser optical axis and elimination of undercuts were achieved by airflow through the nozzles. In spot irradiation of copper using a blue laser, it was confirmed that fumes could be controlled by airflow and that the gas flow and suction by the nozzle produced differences in oxygen content at different processing positions.