Pure Copper Coating Layer Formation via Uniform Heating of Metal Powders and Substrates Using Multi-Beam Metal Powder Deposition with Rectangular Profile Blue Diode Lasers

A high-efficiency, high-quality coating technology for pure copper was developed using a multi-beam metal powder deposition method with a rectangular beam profile at the processing point. Pure copper is a metal with antibacterial properties and high thermal and electrical conductivity. Its use in multi-material applications via metal powder deposition is expected to conserve resources and further expand its applications. In this study, a pure copper layer was formed on a stainless-steel substrate using a blue diode laser with high light absorption in pure copper and a rectangular top-hat beam capable of uniform heating of both the substrate and pure copper powder. Compared with a circular beam, the rectangular beam improved layer formation efficiency up to twofold and was also found to reduce dilution, the mixed layer between the layer and substrate. The pure copper layer formed using the rectangular beam exhibited a smaller difference in dilution between the center and edge of the cross-section compared to the circular beam. This demonstrates that the rectangular beam achieves uniform heating, which is beneficial for layer formation using the multi-beam metal powder deposition method.