(58e) Flow Assessments of Selective Laser Sintering Powders Via Fluidized Bed Rheology on a Rotational Rheometer

Selective Laser Sintering (SLS) is a rapidly expanding field of additive manufacturing technology where manufacturing is done by adding consecutive powder material layers followed by sintering of these layers. There are about a dozen of available additive manufacturing technologies but SLS is considered to be the most favorable for production of plastic parts. One big challenge which is limiting widespread use of this technology is the narrow availability of applicable polymers. Currently strict criteria are applied towards the sphericity of the particles as well as having an extremely narrow size distribution, this puts a considerable strain on the manufacturers of such powders, especially cost wise, and severely limits the widespread availability of exotic materials for high performance engineering purposes. The different properties of powders which influence SLS can be divided into intrinsic (thermal, optical, rheological) and extrinsic (powder flow and particle size). This talk will focus on extrinsic properties especially characterization of flow properties of SLS powders via fluidized bed rheology on a rotational air bearing rheometer. In this study several raw materials ranging from high density metal to low density polymer powders have been used. The work includes flow characterization of SLS powders with a suite of different experiments which include tensile strength, rotational cohesion strength, penetration, oscillation, shear rate sweep etc measurements on an air bearing rotational rheometer. The results are compared and discussed both from the standpoint of particulate mechanics as well as the perspective of the practical process engineer.