Effect of blue diode laser intensity on welding of pure copper wire using blue-IR hybrid laser

A welding of a pure copper wire was conducted with a hybrid laser system, which combines a blue laser and an infrared (IR) laser to achieve a highly efficient and spatterless laser welding of pure copper. In the experiment, a blue-IR hybrid laser was irradiated onto a 3 × 3 × 20 mm3 pure copper wire, and the intensity of the blue laser was varied to clarify the effect of the combining of the blue diode laser. While irradiating the laser, the sample was observed by using a high-speed video camera, and the temperature of the processing point was measured by using a thermal camera. After laser irradiation, a molten volume and welding efficiency was evaluated. It was clarified that the welding efficiency of the pure copper wire increased as the intensity of the blue laser increased. At the maximum, the welding efficiency with a 6.31 × 107 W/cm2 IR laser became 1.88 times higher by combining a 9.98 × 105 W/cm2 blue laser. This finding can contribute to a further increase in the welding efficiency of pure copper wires, leading to high production efficiency in the pure copper welding process.