Experimental and numerical analysis of compaction of fine powder bed under artificial high gravity for additive manufacturing

Additive manufacturing (AM) has advanced rapidly, expanding its applications across various fields. A key challenge in AM is fabricating fine, high-precision parts, which requires uniform and densely packed powder layers. While fine particles (<20 μm) hold promise for these components, their poor flowability and compactability present significant obstacles. This paper presents an experimental and numerical study on overcoming these limitations through high artificial gravity. Fine Inconel 625 particles immersed in epoxy adhesive were compacted using a lab-scale centrifuge at 1010G, 2030G, and 2810G, and a customized large-scale centrifuge at 71.7G, 101.6G, and 123G. The packing fraction of the green body increased up to 0.52 in the lab-scale centrifuge and up to 0.35 in the customized centrifuge. A validated Discrete Element Method (DEM) model simulated compaction of a fine metal powder bed without epoxy adhesive at various gravitational levels, confirming an 82.8 % improvement in packing fraction, reaching 0.53. Cross-sectional analysis of materials produced by laser melting of fine-particle powder beds without epoxy adhesive revealed substantial voids in samples fabricated under normal gravity. In contrast, samples produced under high artificial gravity (71.7G) exhibited significantly reduced void formation.