High-speed welding of copper wires by high-power coaxial blue-IR hybrid laser with galvanometer scanner

A hybrid laser welding system was developed to enable high-speed, spatter-suppressed joining of pure copper conductors, aimed at applications such as electric motor manufacturing. The system combines a 2 kW infrared (IR) single-mode fiber laser with a 3 kW blue diode laser, along with a high-speed galvanometer scanner for precise beam control. The blue laser, exhibiting high absorption in solid copper, initiates rapid surface melting, while the IR laser efficiently forms a keyhole by leveraging enhanced absorption in the liquid phase. Experiments on 2 × 4 mm copper wires revealed that increasing the scan speed reduced weld size, primarily due to decreased energy absorption associated with shallower keyhole formation. Spatter evaluation using high-speed imaging showed a significant reduction in spatter at higher scan speeds. A scan speed of 1500 mm/s was identified as optimal, achieving a weld length of 2 mm within 0.15 s while minimizing spatter. These results demonstrate the effectiveness of the hybrid laser configuration in achieving efficient, high-quality copper welding suitable for high-throughput industrial applications.