Welding of pure copper wires using a hybrid laser system with a blue diode laser and a single-mode fiber laser
Shumpei Fujio, Yuji Sato, Keisuke Takenaka, Rika Ito, Masatoshi Ito, Masayuki Harada, Takashi Nishikawa, Tetsuo Suga, Masahiro Tsukamoto
Abstract
Highly efficient welding of pure copper was achieved using a hybrid laser system, which combined a blue diode laser and a single-mode fiber laser. Pure copper is used as a motor coil for electric vehicles (EVs). However, the processing efficiency of laser welding for pure copper is low since it has a low light absorption rate for the wavelength of the fiber laser. In this study, a hybrid laser system, which combined coaxially with a blue diode laser and a high-power single-mode fiber laser, was developed to realize highly efficient laser welding for pure copper. The beam profile of hybrid laser was alimented to set a stair-shape beam at the processing point. To investigate the effect of the beam profile, the hybrid laser was irradiated onto a 3 × 3 × 20 mm3 copper wire for welding, and the molten volume of copper wire was evaluated. As a result, it was found that the molten volume with a blue diode laser became 1.8 times larger than that without it. Moreover, the welding efficiency of the hybrid laser was 1.45 times higher than that of the fiber laser only.