Particle scale modelling of porosity formation during selective laser melting process using a coupled DEM _ CFD approach

Joint 5th International Conference on Advances in Solidification Processes;5th International Symposium on Cutting Edge of Computer Simulation of Solidification, Casting and Refining

土木建筑工程;计算机科学

Aggarwal, Akash^1 ; Kumar, Arvind^1

Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur

208016, India^1

关键词: Conventional manufacturing;    Enhanced resolutions;    High energy densities;    Open-source code;    Physical phenomena;    Porosity formation;    Selective laser melting (SLM);    Surface finishes;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/529/1/012001/pdf
DOI  :  10.1088/1757-899X/529/1/012001

来源: IOP

【 摘 要 】

Selective Laser Melting (SLM), the most popular metal additive manufacturing (AM) process, is well suited for making complicated parts which are difficult to manufacture by conventional manufacturing techniques. Currently, the main bottlenecks inhibiting the usage of the Selective Laser Melting (SLM) parts include the problems, such as porosity, low resolution, low surface finish quality and low build rate. In order to overcome the aforesaid problems, latest SLM machines are now being equipped with laser having small spot radius for enhanced resolution and surface finish, and high power to increase the build rate. The combination of high power and small spot radius leads to high energy density, exceeding the threshold value, resulting in transition of melting mode in the SLM process from conduction mode to keyhole mode and a formation of porosity due to collapsing of keyhole. In this study, high fidelity particle scale model is developed using open-source codes LIGGGHTS and OpenFOAM to understand the formation of porosity and to describe the physical phenomena (convection, melting, evaporation and solidification), melt flow dynamics and melting mode transition occurring in the SLM process.