SLA vs FDM 3D Printing: When to Use Each
Choose SLA (resin) for high-detail visual prototypes, dental models, and smooth jewelry-like surfaces. Choose FDM (filament) for functional engineering parts, large brackets, and any application needing real engineering thermoplastics like ABS, PETG, or polycarbonate.
SLA and FDM serve completely different prototyping needs. SLA wins on visual quality; FDM wins on function and cost.
Quick Decision Rule
- Need it to **look perfect**? → SLA - Need it to **work mechanically**? → FDM (or MJF for tougher parts) - Need it **cheap and fast for a fit-check**? → FDM
SLA vs FDM
| Property | SLA | FDM |
|---|---|---|
| Layer height | 25–100 µm | 100–300 µm |
| Surface finish | Smooth, glossy | Visible layer lines |
| Materials | Photopolymer resins | ABS, PLA, PETG, Nylon, PC |
| Strength | Brittle (most resins) | Strong & tough |
| Heat resistance | Low (50–80°C typical) | Up to 110°C (PC, ABS) |
| Best for | Visual, dental, jewelry | Engineering, brackets, jigs |
| Cost (small part) | €10–30 | €5–15 |
Frequently asked questions
- Are SLA parts strong enough for functional use?
- Most SLA resins are brittle compared to FDM thermoplastics. Tough/engineering resins exist but cost 2–3× more and still trail FDM in impact resistance.
- Can FDM achieve a smooth surface?
- Not natively — FDM shows layer lines. Vapor smoothing (ABS) or sanding can improve finish but adds labor cost. For smooth parts, choose SLA or MJF.
- Which is better for outdoor use?
- FDM with ASA or PETG. SLA resins typically yellow and become brittle in UV exposure within weeks.