Comparative evaluation of powder spreading strategies to enhance powder bed quality in powder bed fusion additive manufacturing: A DEM simulation study
Seungkyun Yim, Hao Wang, Kenta Aoyagi, Yamanaka Kenta, Akihiko Chiba
Abstract
In this study, we proposed alternative spreading techniques aimed at enhancing the powder bed properties in powder bed fusion additive manufacturing, utilizing discrete element simulations. Our findings revealed significant alterations in the powder spreading regime depending on the adopted spreading strategies. In powder spreading with two blades, the climbing regime in the powder pile was eliminated due to the high compressive condition. The powder spreading with two blades can enhance the homogeneity of the powder bed by maintaining a steady powder pile throughout the spreading process. The spreading with the funnel resulted in superior packing density and reduced surface roughness by effectively mitigating surface pores and loosely packed regions. The force arch formation in spreading with the funnel was suppressed throughout the spreading process, facilitated by rapid kinetic energy dissipation within the downsized powder pile. The high cohesive force of powders reduces packing density during the conventional spreading process, promoting the formation of surface pores. In spreading with the funnel, the influence of cohesive force on force arch formation and packing density was alleviated. Compared to conventional spreading techniques, spreading with the funnel improved both packing density and homogeneity of the powder bed under various gravity magnitudes. Therefore, it was demonstrated that the powder bed quality can be improved by employing the powder spreading with funnel, regardless of powder properties or gravity levels. • Alternative spreading techniques are suggested to enhance powder bed density and homogeneity. • Homogeneity of the powder bed can be improved using powder spreading with two blades by maintaining a steady powder pile. • Powder bed density and homogeneity were improved using powder spreading with a funnel, facilitated by rapid kinetic energy dissipation within the downsized powder pile. • Influence of cohesive force and gravity was minimized in powder spreading with a funnel due to the downsized powder pile.