Polymer Powder-Bed Additive Manufacturing: SLS, MJF, HSS and SAF

Polymer powder-bed fusion contains several architectures that share sequential powder spreading but create selective consolidation differently. Laser PBF, commonly called selective laser sintering, scans a focused energy source. Multi Jet Fusion, High Speed Sintering and Selective Absorption Fusion pattern radiation-absorbing or boundary-modifying fluids and use bed-wide infrared exposure within system-specific thermal strategies. This qualitative engineering review follows all four routes from released powder to accepted component. It examines particle size and shape, flow and packing, moisture and storage, spreading, preheat, optical and agent coupling, coalescence, crystallisation, repeated hot exposure, cooling, distortion, powder segregation and refresh, nesting, internal depowdering, surface state, porosity, anisotropy, post-processing, safety, complete-cell throughput and qualification. Primary studies demonstrate that powder ageing depends on bounded material and exposure histories; coalescence is non-isothermal and rheology-dependent; build position and geometry can alter thermal, dimensional, surface and mechanical states; and surrounding powder does not guarantee recoverable internal passages. No universal reuse percentage, energy-density formula, isotropy claim or dimensional rule survives transfer across polymers, machines and architectures. The resulting selection gate requires traceable powder genealogy, build-layout control, measured thermal and delivery states, qualified recovery and inspection, and accepted-component yield. Metal PBF, construction-scale systems, bound powders and ceramic sintering are outside scope.

3Dresyns Engineering Review ER-141, version 0.2. Provider-neutral technical review.