Chapter Five - Discrete element modeling of powder flow and laser heating in metal laser powder bed fusion process

Abstract

In this chapter, a particle-based discrete element model (DEM) is developed to simulate the laser powder bed fusion process, which includes simplified powder deposition, recoating, laser heating, and holding stages. This model is validated through the simulation of particle flow and heat conduction in the powder bed, and the simulated results are in good agreement with either experiment in the literature or finite element method. Then the validated model is employed to the powder bed fusion process. The effects of laser power, laser scan speed, and hatch spacing on the temperature distributions in the powder bed are investigated. The results demonstrate that the powder bed temperature rises as the laser power is increased. Increasing laser scan speed and laser hatch spacing will not affect the average temperature increase in the powder bed since energy input is kept the same. However, a large hatch spacing may cause nonuniform temperature distribution and microstructure inhomogeneity.