Technology · SLA / DLP
SLA 3D printing for high-resolution and finely detailed parts
Stereolithography and DLP resin printing for visual prototypes, master patterns, injection-mould inserts, microfluidics, dental and jewellery. Layer heights from 25 microns.
Minimum layer height
- 1Upload STEP or STL file
- 2Engineer selects resin and orientation
- 3We print, wash, UV-cure and finish
- 4Ship in 3–5 business days
Quick answer
SLA (Stereolithography) cures liquid photopolymer resin with a UV laser or projector, layer by layer, producing the smoothest surface finish and finest features of any mainstream additive process. Use it for visual prototypes, master patterns for silicone moulding, microfluidics, injection-mould inserts, dental and jewellery work. Typical lead time is 3–5 business days at 25–100 micron layer resolution.
Applications
What SLA is good for
Where resin printing beats FDM and SLS on finish, feature size and material specialisation.
- Visual and presentation prototypes with class-A surface finish
- Master patterns for silicone moulding and vacuum casting
- Injection-mould inserts and low-volume tooling in High-Temperature resin
- Microfluidic and optical parts with clear or polished finishes
- Dental splints, surgical guides and hearing-aid shells in biocompatible resins
- Castable patterns for lost-wax jewellery, dental and small metal casting
- Fit-check jigs and inspection fixtures with tight tolerances (±0.05 mm)
- Concept models with fine embossed text, logos and detail below 0.3 mm
- Flexible gaskets and vibration dampers in Elastic 50A / Flexible 80A
Process
How SLA printing works
From uploaded 3D file to finished cured part, the SLA workflow at 3DadditHub.
File review and DFM
Our engineers check the file for min wall thickness (0.4 mm), trapped-resin cavities, support strategy and orientation for the intended finish.
Slice and orient
Parts are oriented to minimise support marks on cosmetic faces and reduce distortion. Layer height (25, 50 or 100 µm) is set to the spec.
Print in the vat
A UV laser (SLA) or DLP projector cures each layer in a vat of liquid resin. Print time depends on Z-height, not part count on the platform.
Wash, cure and finish
Parts are washed in IPA, supports removed, UV post-cured to full strength, then sanded, polished or coated depending on the spec before shipping.
Specs
Resins, resolution and build volume
Common SLA resins
- Standard / Clear — visual prototypes, tensile strength ~65 MPa, brittle.
- Tough 2000 — ABS-like, notched Izod resilience for snap-fit and clips.
- Durable — PP-like, low friction, elongation at break ~55%.
- Rigid 10K — glass-filled, flexural modulus ~10 GPa, HDT ~218 °C.
- High-Temperature — HDT up to 238 °C at 0.45 MPa. Mould inserts.
- Elastic 50A / Flexible 80A — Shore 50A–80A, gaskets and soft-touch parts.
- Castable Wax — 20% wax, burnout residue < 0.02% for lost-wax casting.
- Biocompatible (Class I / IIa) — dental, surgical guides, medical.
Print specifications
- Layer height: 25, 50 or 100 µm.
- Dimensional tolerance: ±0.1 mm or ±0.1% (whichever is greater); ±0.05 mm on small features.
- Minimum wall thickness: 0.4 mm (0.6 mm for reliability).
- Minimum embossed / engraved detail: 0.15 mm.
- Maximum build volume: 335 × 200 × 300 mm on Form 3L class; larger on request.
- Finishes: as-printed glossy, sanded matte, polished clear, painted, plated.
- Isotropy: effectively isotropic after full UV post-cure.
Typical case
A real-world SLA order
A consumer electronics team validating a wearable enclosure needed 15 pre-production visual prototypes in clear polished resin with a soft-touch overmoulded gasket area. We printed the housing in Clear resin at 50 µm, sanded and polished to optical transparency, then printed the gasket in Elastic 50A and bonded it in place. Unit cost landed at €62 per prototype and the full batch shipped in 72 hours from file receipt, in time for the client's user-testing session the following week. Two design revisions later, the same team moved to SLS Nylon for the pilot production run.
Decision guide
When to choose SLA vs FDM, SLS or MJF
- Choose SLA over FDM when surface finish, fine features or transparency drive the spec.
- Choose SLA over FDM for master patterns for silicone moulding — smooth walls mean fewer secondary steps.
- Choose FDM over SLA when you need real engineering thermoplastics (PC, PA-CF, ULTEM) or parts above 300 mm.
- Choose FDM over SLA for UV-exposed, high-temperature or long-term structural end-use parts.
- Choose SLS or MJF over SLA at 20+ functional Nylon parts — better mechanical properties and volume economics.
- Choose SLA over SLS/MJF when the part needs to be transparent, biocompatible or castable for metal casting.
- Choose SLA over CNC for organic geometries, undercuts and internal features not machinable in one setup.
- Choose castable SLA over lost-wax hand carving in jewellery and dental — same result, hours instead of days.
FAQ
SLA 3D printing — frequently asked questions
SLA (Stereolithography) is a vat-photopolymerisation process that cures liquid photopolymer resin with a UV laser or projector (DLP/LCD variants) layer by layer. It produces the smoothest surface finish and finest feature resolution of any mainstream additive process. Layer heights start at 25 microns and printed features can be as fine as 0.1 mm.
Ready to quote your SLA part?
Upload a STEP or STL file. Our engineers suggest the right resin for your surface, feature and mechanical requirements and reply with a technical quote within 24 hours.