Design Nomenclature / Physical Model Making
SLS
Also called selective laser sintering, powder bed fusion, MJF, Multi Jet Fusion, nylon printing
Fusing nylon powder in a heated bed layer by layer, with the unfused powder supporting the part. No support structures at all, so geometry no other process can build comes out in one piece: living hinges, captive parts, deep undercuts. Surfaces are uniformly matte and slightly porous — they dye beautifully and paint badly.
In practice
MJF fuses with an inkjetted absorber and a lamp rather than a laser. Different machine, near-identical design rules, and shops quote them interchangeably.
Not to be confused with
- FDMExtruding molten thermoplastic in stacked paths. Cheap, forgiving, dimensionally decent. But the part is a stack of welded beads: strong along the paths, roughly half as strong across them. Layer lines are visible, overhangs need support, and the first layer decides whether the print survives the night at all.
- SLACuring liquid photopolymer layer by layer with light. Resolution is set by optics rather than a nozzle, so fine detail and smooth walls come easily. The trade is real: parts arrive wet with uncured resin, need washing and a post-cure to reach final properties, and stay brittle and UV-sensitive for life.