(84c) Characterization of Polymeric Powders through Capillary Flow for Additive-Manufacturing Techniques

Binder jetting is an additive-manufacturing (AM) method that deposits a liquid binding agent onto a powder surface in a layer-by-layer fashion to form a solid part from a computer-aided-design (CAD) file. Powders that are utilized in AM include polymers, sands, and metals. The production of parts requires input materials to have quantifiably repeatable characteristics and properties, which then requires standardized methods of characterization for powders. In this investigation, we use a non-invasive frugal imaging technique to characterize fluid flow in a packed powder bed to investigate fluid-powder interactions. Laser- diffraction particle size and sieve analysis are used for size and shape analyses, as well as scanning electron microscopy (SEM) to investigate the surface topography. The results of this study demonstrate how particle size, size distribution, particle shape, surface roughness, and surface chemistry affect the packing density and therefore the binder-jetting process.

This study investigates the interactions of the polymer powders with fluids at the fundamental level. Results will aid in the understanding of other AM methods (e.g., cold spraying, drop on demand (DOD), selective laser sintering (SLS), electron beam melting (EBM)), which use polymer powders. Since this study uses a frugal technique, which requires only a mobile phone and a flow cell to analyze the fluid-powder interactions, characterization of the properties of any polymer powder is readily available to all industries.