Model of the Selective Laser Melting Process-Powder Deposition Models in Multistage Multi-Material Simulations

Abstract

This paper presents one of the final stages in the development of a holistic model of the selective laser melting (SLM) process. The holistic model developed previously allows for modeling of only one stage of SLM, which limits simulations to one cycle with one material. The lattice Boltzmann method is applied for simulation of laser treatment, melting, fluid flow, and solidification. Several models of powder bed generation were developed within the framework of the holistic model and are described in this paper. They were developed on the basis of static and dynamic physical principles with the use of cellular automata, their own code, and the Unity® platform. They employed continuous and discrete particle representation and incorporated a model of powder deposition with particles of atomized or arbitrary shape. The closing of the external simulation circuit, which contains the powder bed generation model, cycle initialization, its realization by the model based on the Lattice Boltzmann Method (LBM), and the powder removal model, allows us to finish one simulation cycle of laser treatment and initialize the next, thereby enabling multistage multi-material simulations. The simulation results of the multistage SLM process with the Ti-6Al-V alloy and bioactive glass are presented in this paper. These simulation results confirm the possibility of modeling several SLM stages with two different materials. The holistic model can be used for simulation, design, and optimization of multistage, multi-material SLM processes.

Computational Framework to Model the Selective Laser Sintering Process

“…The finite volume method (FVM) is also employed because of its conservative nature, helping to surpass some limitations present in the FEM [14]. Since mesh-free and mesh-based methods present distinct advantages, some researchers couple them to simulate separate steps [15,16].…”

“…When metals are employed, the process is known as selective laser melting (SLM), in which case different models are required for the powdered and liquid state due to their distinct properties [16,17]. Indeed, most of the literature is dedicated to the SLM process, whereas the SLS is not so well developed.…”