Parametric Study of SLM Processing Parameters on In-Situ Residual Stress

Abstract

Abstract Additive Manufacturing (AM) particularly laser powder-bed fusion, is advancing rapidly in manufacturing industries. Selective laser melting (SLM) also known as 3D-printing has become one of the most recent developed and extensively used techniques for several manufacturing processes. However, processing parameters influence the defect formation mechanisms such as porosities, holes, cracks, incomplete fusion and molten pool configuration during the SLM process of metallic powders. Even though an extensive amount of work have been done in minimizing these defect formations by simply varying processing parameters such as laser power, deposition thickness and scanning speed, it is of great importance to study the heat transfer mechanisms in laser heating process and utilize the optimum process parameters in minimizing the residual stress and strain as well as improving the quality of a manufactured product. In this present work, the authors implement a numerical thermo-mechanical model approach to determine the residual stress and strain in 316L Stainless Steel built samples using a finite element method (FEM) software ANSYS® (Workbench version 19.0). We are able to predict the unsteady temperature distribution of temperature-dependent thermal properties, residual stress and strain as a result of the rapid melting and solidification of 316L Stainless Steel metallic powder with optimized processing parameters. From the simulation result, it is shown that the residual stress decreases with an increase in scanning speed, hatch distance and preheat temperature. However, an increase in melting temperature also increases the residual stress and strain in the simulated 3D built part.