Numerical analysis of hardness variations for a dome built without supports using directed energy deposition and multi-axis tool paths

• Published in: International journal of advanced manufacturing technology 2021-09, Vol.116 (3-4), p.975-991
• Main Authors: Kalami, Hamed, Urbanic, Jill
• Format: Article
• Language: English
• Subjects: Beads; CAE) and Design; Computer-Aided Engineering (CAD; Deposition; Diameters; Domes; Engineering; Finite element analysis; Finite element method; Hardness; Industrial and Production Engineering; Mechanical Engineering; Media Management; Metallurgy; Numerical analysis; Original Article; Process parameters; Substrates
• ISSN: 0268-3768; 1433-3015
• DOI: 10.1007/s00170-021-07504-6

There are many process parameters for directed energy deposition (DED) that influence product quality. Using a well-defined analytical model to simulate the process increases the knowledge of the process. In this paper, a finite element analysis of hardness and temperature history for a thin-wall hemisphere dome is investigated using the SYSWELD software. The dome diameter and thickness are 45 mm and 2 mm respectively, and 144 beads of varying lengths is required to fabricate this part without support structures. A three-dimensional thermo-metallurgical-mechanical solution is used to generate the hardness. Two approaches for heat input are applied: constant laser efficiency and constant melt pool size. The results show a reasonable match between the experimental hardness data and the finite element analysis. The numerical results correlated better for the base segments than for those built at the top. Influence factors vary as the component is built, as conduction into the substrate occurs for the base partitions, but convection and radiation influence the heat losses at the top for thin-walled components. This illustrates the challenges with respect to developing accurate results. Faster numerical analysis techniques need to be developed to simulate products fabricated by DED additive manufacturing processes.