Theoretical Description of Powder Delivery to Direct Laser Deposition Area

BACKGROUND: The parameters of powder flow delivered to the direct laser deposition area affect the interaction of the powder, laser, and melt pool, directly determining the bead shape and the quality of the deposited material. Controlling the spatial distribution of powder flow in the processing area is key for improving the process performance and repeatability. AIM: To develop a semi-analytic approach to find powder particle trajectories in the problem of direct laser deposition using a discrete jet nozzle. METHODS: The carrier gas flowfield in an unobstructed half-space filled with a protective gas is approximated by an analytical solution of the Euler equation. Powder trajectories are determined by numerical integration of the equation of motion based on the Stokes’ law. RESULTS: Powder trajectories are determined by the distribution of the carrier gas velocity at the tube outlet by applying the exact solution of the Euler equation for specific parameters of powder particles and carrier gas used in additive manufacturing. CONCLUSION: The paper presents an elementary semi-analytic model of powder delivery in the problem of direct laser deposition allowing to obtain the spatial distribution of powder particles in the processing area.