When to pick SLA tough resin
Photopolymer SLA achieves Ra < 2 µm and feature sizes below 100 µm — by a wide margin the highest-resolution AM process. Tough resins (Formlabs Tough, Tough 1500, etc.) deliver ABS-like ductility with high surface fidelity.
Pick SLA tough resin for functional prototypes that need to look like an injection-molded part, dimensionally critical fixtures, and snap-fit assemblies.
Defects and post-processing
Uncured resin trapped in cavities is the dominant defect mode. Wash thoroughly in IPA and post-cure under UV — without post-cure, parts retain ~40 % of their final strength.
Tough resins are sensitive to long-term sunlight exposure. For outdoor or sustained UV applications, look at ASA-equivalent FFF or SLS PA12.
Suggested parameters
Form 4 standard process at 100 µm layer.
- Layer thickness: 50–100 µm
- Print speed: ~40 mm/h vertical
- Wash: 20 min in IPA
- Post-cure: 60 min @ 60 °C UV oven
- Support density: low for vertical walls, high for overhangs > 30°
Frequently asked questions
Is SLA tough resin a real injection-molding substitute?
For appearance and dimensional checks, yes. For load-bearing use over months/years, no — photopolymers creep and yellow.
How does it compare to MJF for prototypes?
SLA wins on surface finish and small-feature resolution. MJF wins on durability, isotropy, and per-part cost at volume.
Sources
- Formlabs Tough 1500 material datasheet
- ASTM F2792 — Standard Terminology for AM Technologies (deprecated; reference)