PSI has been working in fluidised bed technology for several years in the processing of metal and ceramic powders. In very simple terms an FBR is a container of powder, generally housed in a pressure or vacuum containment vessel. At the base of the container is a porous plate through which a whole variety of heated gases may be passed, inert or reactive in nature. The gas flow energises the powder (fluidises) so it appears to the naked eye as a pot of boiling liquid.
Additive Manufacturing drives spherical powder development at PSI (metal-am.com)