Design Nomenclature / Physical Model Making
SLA
Also called stereolithography, DLP, MSLA, resin printing, vat photopolymerisation
Curing 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.
In practice
The shop says "resin printer" for SLA, DLP and LCD alike. The difference is the light source; the workflow, the smell and the mess are identical.
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.
- SLSFusing 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.