Fundamental Study on the Effect of Nozzle Cross-Sectional Geometry on Molding Patterns of Copper in Cold Spray Additive Manufacturing

Abstract

Cold spray (CS) is a coating deposition process in which material particles in a solid state are impacted onto a substrate. Cold spray additive manufacturing (CSAM) is attracting attention as a new method for additive manufacturing, an additive manufacturing technology that takes advantage of the features of CS. Compared to other metal AM processes, the advantages of CSAM include reduced manufacturing time, unlimited product size, flexibility to adapt to complex geometries, and suitability for damaged component repair. On the other hand, the coating profile deposited by CS becomes triangular due to the decrease in particle velocity near the nozzle tube wall caused by tube friction and the decrease in the number of particles from the center of the nozzle to the edge of the nozzle. Therefore, the cross-section of the CSAM modeling object becomes sharply triangular as coatings are laminated. In this experiment, the rectangular nozzle, which is effective in flattening the spray pattern, is traversed in the short side direction for molding. The behavior of the working gas and copper particles on the molding pattern of the molding object at each nozzle was investigated and discussed using Computational Fluid Dynamics (CFD) analysis. As a result, the molding pattern obtained by traversing the rectangular nozzle in the short side direction was relatively flatter.