A Control of Surface Quality in Selective Laser Sintering Additive Manufacturing with Reclaimed Polyamide Materials
Abstract
In selective laser sintering (SLS) additive manufacturing (AM), a substantial amount of
polyamide 12 materials remains un-sintered, recyclable, and reusable. However, using reclaimed
polyamide 12 powder in SLS results in undesirable part surface finish. Very limited research has
been done on the improvement of part surface quality and results barely exist on improving or
modifying the surface quality of parts using extremely aged powders (powders held close to the
heat-affected zones). Aiming to improve the surface quality, we propose a novel approach for
SLS with (extremely) aged polyamide 12 powders. By combining material preparation, powder
and part characterizations, and SLS with a customized method of post-heating, we obtain parts
with improved surface quality (e.g., reduced roughness and porosities, and eliminated un-sintered particles). Particularly, parts 3D-printed using the 30%-30%-40% new-aged-extremely
aged mixed powders exhibit the smoothest and flattest surface with no unmolten particles and
nearly zero porosity.