Vibratory Powder Feeding for Powder Bed Additive Manufacturing Using Water and Gas Atomized Metal Powders

Abstract

Commercial powder bed fusion additive manufacturing systems use re-coaters for the layer-by-layer distribution of powder. Despite the known limitations of re-coaters, there has been relatively little work presented on the possible benefits of alternative powder delivery systems. Here, we reveal a feeding technology that uses vibration to control flow for powder bed additive manufacturing. The capabilities of this approach are illustrated experimentally using two very different powders; a ‘conventional’ gas atomized Ti-6Al-4V powder designed for electron beam additive manufacturing and a water atomized Fe-4 wt.% Ni alloy used in powder metallurgy. Single layer melt trials are shown for the water atomized powder to illustrate the fidelity of the melt tracks in this material. Discrete element modelling is next used to reveal the mechanisms that underpin the observed dependence of feed rate on feeder process parameters and to investigate the potential strengths and limitations of this feeding methodology.

Electron Beam Powder Bed Fusion of Water Atomized Iron and Powder Blends

“…The WA powder might be modified, e.g., by milling or mixing with modifiers to improve flowability. Finally, modification to the powder feeding mechanism could improve the quality of spread layers [26]. (2) Blending inexpensive base feedstock with alloying elements offers higher flexibility in additive manufacturing, as there is no need for atomization of each individual alloy composition.…”

Novel Assessment Methodology for Laser Metal Deposition of New Metallic Alloys

“…The sample fabricated by MS showed a similar supersaturated structure to the PBF counterpart and both samples exhibited analogous microstructures. Sinclair et al [ 23 ] used water-atomized powder as raw material and developed a feeding technology for Powder Bed Fusion (PBF) that used vibration to control the flow of powders. They used low ‘spreadability’ water-atomized metal powders owing to their significantly lower cost in comparison to gas-atomized powders.…”