Molten pool behaviors and forming characteristics in wire-laser directed energy deposition with beam oscillation

Abstract

This research proposes a novel variant of wire-laser directed energy deposition (DED), named beam oscillating wire-laser DED. In this technique, the laser beam oscillates periodically in an 8-shape or infinite pattern to control the forming quality and geometries of the deposited layer. The novelty is that how the laser oscillating pattern, frequency, and amplitude affect the forming qualities and deposition layer dimensions. The study investigates the dynamic behaviors of the molten pool and the generation mechanisms of various forming defects. A comparison is made with non-oscillating wire-laser DED regarding the thin-wall part’s forming qualities. The results reveal that the layer width of the 8-shape oscillating sample increases when the oscillating amplitude increases. However, the infinite oscillating sample behaves inversely. The width-to-height ratio of the deposition layer varies from 2.04 to 5.18 by changing the laser oscillating pattern and amplitude. Compared to non-oscillating wire-laser DED, the surface quality and the structure density of the deposited walls by beam oscillating wire-laser DED show remarkable improvement. The wall’s material utilization rate is increased by 22.2 % with the 8-shape oscillation. This study demonstrates the ability of beam oscillating wire-laser DED to control the deposition layer dimensions and improve the forming quality without compromising the deposition efficiency.