Formation of a low-dilution pure copper layer by wire-based laser metal deposition with blue diode laser

A pure copper layer was formed on the stainless-steel substrate with low-dilution layer by a Wire-based Laser Metal Deposition method (W-LMD) with a blue diode laser. Pure copper is an important material for realization of a carbon-neutral society because of excellent properties such as electrical and thermal conductivity. As the demand of copper increases, a wide variety of processing methods are required with high yields. Thus, the LMD method, which is one of the Additive Manufacturing (AM) technologies, is focus on this study. The W-LMD is the process in which a metal wire is fed to the laser irradiation point and melted and solidified to form a layer. Conventional W-LMD with near-infrared fiber laser has formed a layer of Fe-based alloy, Ti-based alloy, Ni-based alloy, and so on. However, it was difficult to form a pure copper layer since light absorption rate of copper in this region was less than 10%. Therefore, we focused on blue light at the wavelength 450 nm. It is because light absorption rate of copper in blue region is 60%. Thus, the high-power blue diode laser has been developed and installed the W-LMD system. In this study, the pure copper layer was tried to form on the SS304 substrate with our W-LMD system. As the results, copper layer was formed with a layer thickness of 388 μm and a dilution thickness of 22 μm at the output power of 500 W, stage sweep speed of 10 mm/s, and wire feeding rate of 10 mm/s.