Modeling of Deposition Geometry in Laser Directed Energy Deposition over Inclined Surfaces for Restoration and Remanufacturing

Additive manufacturing has gained much popularity in the last decade because of its flexibility and sustainability. One of the leading additive manufacturing processes is laser-directed energy deposition (LDED). In addition to building three-dimensional free-form features, LDED has a huge potential in the repair and reconditioning segment of the industry. A variety of valuable components such as dies, molds, turbine blades, valves, etc. subjected to high thermal and mechanical loads develop surface defects over time. These components can be restored to their functional condition using LDED instead of replacing them. The material similar to substrate material or even better can be deposited using LDED. These components generally possess complex free-form features and contours, which makes it difficult to perform depositions keeping the deposition head vertical and requires the deposition head to be inclined to the desired inclination angle, which may affect the powder catchment and the deposition geometry. The effect of the inclination angle on the catchment and the deposition geometry needs to be studied for a better understanding of the DED process. In this paper, the different strategies of deposition over inclined surfaces have been studied. Based on the experimental results, a phenomenological model is developed to predict the powder catchment efficiencies at depositions with different inclinations. The inclination not only affects the effective powder reaching the melt pool but also affects the shape of the deposition. A two-dimensional computational fluid dynamics (CFD) model has also been developed, which predicts the shape of the deposition cross-section. The model considers the flow of the melt pool, due to inclination, before solidification. The model captures the effect of inclination angle in terms of reduction in powder catchment efficiency (PCE) and the gravity-driven melt flow effectively.