Enhancement of powder supply efficiency in directed energy deposition based on gas-solid multiphase-flow simulation

Directed energy deposition is an additive manufacturing process which produces deposits by irradiating laser beam on the baseplate and supplying material powder to the meltpool. Although the material powder is generally conveyed with carrier-gas flow, the powders diffuse and some of them do not reach to the meltpool. In order to suppress the waste of materials, the particle movement should be analyzed and modified not only from the viewpoint of deposition conditions but also the nozzle design. Against this background, this paper presents analytical and measurement results of powder distribution under the nozzle and proposes a nozzle design to reduce the waste of material powder based on a gas-solid multiphase-flow simulation. The experimental result of designed nozzle certainly shows high powder supply efficiency of 74.8%, whereas that of the conventional nozzle is 52.6%. (C) 2018 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/)