Prediction of Porosity and its Mechanisms in Metal Additive Manufacturing

Selective Laser Melting (SLM) is an up-and-coming additive manufacturing technique that uses a laser as the power source and is specially developed for 3D Printing metal alloys. SLM advancement is significant since it can create custom property parts, reduce material usage and design freedom, and quickly manufacture complex components. The high energy density of laser generates various unwanted structural defects such as keyholes and porosity, which results in crack formation & distortion, and subsequent reduction in mechanical strength of the components. The present work aims to simulate the relevant physical configurations of the SLM process and identify process parameters and the effect of metal powder variation. A representative model based on Molecular Dynamics (MD) is developed to explore the sintering mechanism of metal powders. Open-source code LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator) has been used to develop a working model to emulate a powder bed consisting of metal particles. The melting phenomenon is simulated by the heating layer of the metal particle bed. The results from this study will be able to predict the onset mechanism of porosity better and crack formation in Metal 3D printed parts.