Powder flow and deposition profile in directed energy deposition with discrete coaxial injection

This study explores the effects of powder injection angle and substrate inclination on powder flow characteristics and deposition profiles in Directed Energy Deposition (DED) using a discrete coaxial nozzle. A multiphase simulation based on the Euler-Lagrange method and Discrete Phase Modeling (DPM) was performed to evaluate particle trajectories, velocity, focal convergence, and deposition geometry across five injection angles (110°–135°) and four substrate inclinations (0°–60°). The results reveal that lower injection angles produce a more stable and focused powder stream, improving deposition quality and efficiency. In contrast, angles above 130° reduce focal precision due to increased divergence and particle collisions. Substrate inclinations greater than 40° shift the peak deposition point and reduce cladding uniformity, indicating sensitivity to geometric orientation. These findings contribute to precision control strategies for DED processes, particularly in complex remanufacturing tasks. As metal additive manufacturing expands in the aerospace industry, integrating artificial intelligence for real-time monitoring and adaptive control can enhance process reliability, reduce material waste, and enable autonomous repairs. The study demonstrates that careful tuning of injection parameters is essential to meet the high-performance demands of next-generation remanufacturing systems.