| Title |
Analysis of Deposition Characteristics of Thin-Wall Structures using the Directed Energy Deposition Process |
| Authors |
한지수(Ji-Su Han) ; 윤종천(Jong-Cheon Yoon) ; 이협(Hyub Lee) |
| DOI |
https://doi.org/10.5370/KIEE.2024.73.3.631 |
| Keywords |
Directed energy deposition; Thin-wall; Computational fluid dynamics; Scan pattern; Heat accumulation |
| Abstract |
Directed energy deposition (DED) is one of the metal additive manufacturing methods. In this process, a high-power laser beam is directed onto a metal powder. The powder is melted and solidified layer by layer to build the desired object. Recently, it has found significant applications in the aerospace sector, particularly for manufacturing thin-wall shapes such as high pressure fuel tank or huge part of aircraft. However, manufacturing thin-wall structures using DED is challenging due to thermal accumulation leading to thermal distortion. Additionally when deposited on narrow surfaces, uneven staking may result in non-uniform deposition surfaces.
To minimize the risk of deposition failures, an analysis of deposition patterns has been conducted. Two different deposition patterns were considered. The Sequence pattern is that layer are deposited continuously from one side, and The Zigzag pattern is that the central bead is deposited first, followed by beads on both sides. Initially Computational Fluid Dynamics (CFD) Simulation were employed to compare both of the deposition about 2-layer deposition on a flat surface and deposition of thin-wall structures. The comparison included analysis of deposition cross-sections, thermal accumulation patterns, and molten pool flow dynamics.
Subsequently, both patterns were fabricated by actual DED processes to observe the difference in thermal distortion when manufacturing thin-wall structures. The cross-sections of the deposited material were analyzed to understand how the deposition patterns affect-micro structure and strength. This study concluded that the choice of deposition pattern is important for thin-wall shapes, and careful consideration necessary when applying these patterns in real DED manufacturing processes. |