Chapter 3　Investigation of optimizing the flow field with fluid cover in Laser-based Powder Bed Fusion manufacturing process

◆ Introduction

◆ Simulation model of L-PBF printer

◆ Simulation results and discussion

◆ Summary and conclusions

Laser-based Powder Bed Fusion （L-PBF） is an additive manufacturing （AM）process where an energy source，such as high-energy-density laser beam，is used to melt the metal powders on the power bed layer-by-layer to form a three-dimensional object. During the manufacturing process，the high-energy laser will produce a large number of sputtered particles while melting the metal powder. After these sputtered particles fall on the workbench again，it will affect the quality of the product. The argon gas flow above the workbench will directly affect the blowing effect of sputtered particles. In this chapter，a fluid stabilizing cover is designed into the metal printer chamber to improve the flow of argon above the workbench，which can blow out sputtered particles more effectively，thereby improving product quality. A Computational Fluid Dynamics （CFD） model coupled with a discrete phase model（DPM） for the flow field in the L-PBF printer is developed to simulate the trajectory of particles sputtered from the workbench. The influence of the fluid stabilizing cover on the flow field above the workbench，the trajectory of the sputtered particles and the blowing effect are all investigated numerically. The results show that the laminar flow height of the argon gas flow above the workbench has increased after using the fluid stabilizing cover，and the flow field distribution at different heights parallel to the workbench has also been greatly improved. The results verify the fluid stabilizing cover is a feasible approach to efficiently improve the uniformity of the flow field above the workbench and the removing rate of spatters.