The influence of spreading metal powders with different particle size distributions on the powder bed density in laser-based powder bed fusion processes

Abstract

In laser powder bed fusion (LPBF) processes, the powder size characteristics, like particle shape, particle size (PS), particle size distribution (PSD), and the resulting powder bed density (PBD), are key influencing factors of the built material properties. To better understand the correlations between the powder size characteristics and the powder properties influencing the LPBF process, apparent density (AD), flowability, and PBD were measured corresponding to two commercial metal powders with different PS and PSD. The powder samples were taken from different locations on the build platform to also investigate the variations of these powder characteristics resulting from the spreading process by the stiff recoater blade. It was shown that the PS and PSD had a significant effect on the AD and the PBD. Powders with a wide PSD and with particle sizes in the range of the effective powder layer thickness, led to a higher PBD than powder with a high proportion of finer particles. No significant differences in PS and PSD were observed as powder was pushed across a build plate by the recoater blade. Key wordsadditive manufacturing; apparent density; metal powder; particle size distribution; powder bed density; powder bed fusion; powder layer; powder layer thickness; powder spreading; selective laser melting; selective laser sintering. iv This publication is available free of charge from: https://doi

Preparation of 3D Printable HAp-based Composite Powder for Binder Jetting Process

“…Consequently, the non-lling of the voids occurs between the larger particles by the ne particles and eventually causes the creation of the cavities. These results are consistent with a report by Jacob et al [52] who found that ner particles moved away from larger particles by accumulating in the lower layers of the powder bed.…”

Optimization of Laser Powder Bed Fusion Processing Using a Combination of Melt Pool Modeling and Design of Experiment Approaches: Density Control

“…These changes in the powder bed density are due to the differences in the powder spreading conditions for different layer thicknesses as demonstrated in [31]. If a layer thickness is smaller than the D90 value of the powder particle distribution [32], the density increases because the biggest particles are kept at the top of the layer and finally swept out by the recoater [33], which increases the powder bed density. It can be seen from Figure 6 that the higher the powder bed density (70%, Figure 6b, instead of 60%, Figure 6a), the higher the optimal laser power density, while the lower the build rate of the process.…”

“…because the biggest particles are kept at the top of the layer and finally swept out by the recoater [33], which increases the powder bed density. It can be seen from Figure 6 that the higher the powder bed density (70%, Figure 6b, instead of 60%, Figure 6a), the higher the optimal laser power density, while the lower the build rate of the process.…”

Hardening of Additive Manufactured 316L Stainless Steel by Using Bimodal Powder Containing Nanoscale Fraction

“…It is established that the higher the powder packing density, the higher the bed thermal conductivity, and the better the mechanical properties of the part [ 4 ]. Jacob et al [ 11 ] found that powders with a wide PSD increase the density of layer packing and decrease the flowability, which is crucial to powder spreading. Liu et al [ 12 ] revealed that gas-atomized 316L steel powder with a narrow PSD provides an improved flowability, leading to a high ultimate tensile strength and robust printed components.…”