How the two processes differ
SLA cures liquid photopolymer resin with a laser, layer by layer. It excels at fine detail, smooth surfaces and thin walls — ideal for appearance models and form-fit checks. SLS fuses nylon powder with a laser. The loose powder supports the part, so no support structures are needed, and the result is a strong, slightly matte functional part.
Pick SLA when…
- You need the smoothest surface and finest detail
- The part will be painted, plated or shown to customers
- You need clear or transparent material
- Geometry is small to medium with fine features
Pick SLS when…
- The part must be strong, flexible or snap-fit
- You have interlocking or internal features that supports would ruin
- You need a small batch (1–200) economically
- Mechanical function matters more than surface gloss
At a glance
| Factor | SLA (resin) | SLS (nylon) |
|---|---|---|
| Surface | Very smooth, paintable | Matte, slightly grainy |
| Strength | Rigid, somewhat brittle | Tough, flexible options |
| Supports | Required, removed post-print | None (powder supports) |
| Best use | Appearance, detail | Function, batches |
Still unsure? Send your file and we'll recommend the best fit during DFM review. You can also read our dedicated pages on SLA printing and SLS nylon printing.