3D printing processes
What is SLA 3D printing, and when should you use it?
SLA (stereolithography) 3D printing cures liquid resin with UV light, layer by layer. Use it for small parts that need fine detail and a smooth surface straight off the machine. On our service, SLA prints layers from 10 microns at ±0.5% (minimum ±0.1 mm) in a 350 × 250 × 250 mm build volume, with lead times from 1 calendar day.
Reviewed by HenleyPrint3D engineers2 min readUpdated
Key takeaways
- Layers from 10 microns; tolerance ±0.5% with a minimum of ±0.1 mm, the tightest of our standard processes.
- Build volume 350 × 250 × 250 mm; lead time from 1 calendar day.
- Resin parts are more brittle than FDM or SLS and degrade under sustained UV.
Suits
Small parts that need fine detail, a smooth surface or a clear finish.
Worth knowing
Not for parts over 350 mm, sustained outdoor use, repeated impact or snap fits.
SLA key figures
| Property | SLA on our service |
|---|---|
| Build volume | 350 × 250 × 250 mm |
| Tolerance | ±0.5% (min ±0.1 mm) |
| Layer height | From 10 microns |
| Minimum wall | 0.5 to 1.0 mm |
| Lead time | From 1 calendar day |
SLA resins
| Resin | Use it for | Watch |
|---|---|---|
| Standard | Finest detail, smooth surfaces | Brittle; suited to indoor, room-temperature use |
| Tough | Functional prototypes | On request |
| Flexible | Gaskets, soft-touch parts | Low stiffness |
| Transparent | Light guides, flow models | Brittle |
| Castable | Investment-casting patterns | Fragile before casting; on request |
When to choose SLA
| Choose SLA when | Choose something else when |
|---|---|
| Detail and surface finish drive the part | The part is larger than 350 mm (use FDM) |
| The part is small and cosmetic | It needs impact toughness or snap fits (use SLS or FDM) |
| You need a clear part | The part sits outdoors in sunlight (use ASA) |
Specifying an SLA part
Name the resin on your quote request, or describe what the part must do and we recommend one. Tough and castable resins are available on request. Resin grades are listed on our SLA materials page, and the SLA 3D printing service page covers ordering and finishing. To compare SLA with the other processes, see FDM vs SLA vs SLS vs PolyJet.
Frequently asked questions
How accurate is SLA 3D printing?
Typically ±0.5% with a minimum of about ±0.1 mm on our service. Layers start at 10 microns, but overall accuracy also depends on part size, orientation and post-cure shrinkage.
Is SLA stronger than FDM?
SLA parts are stiff and detailed but more brittle than most FDM or SLS parts. FDM and SLS nylon are the usual choice for tough, functional components.
Do SLA parts need post-processing?
Yes. They must be washed, have their supports removed and be UV post-cured. Sanding, priming and painting are optional, for a cosmetic finish.
Can SLA parts be used outdoors?
Standard resins can yellow and embrittle with sustained UV exposure. For outdoor use, choose a suitable material such as ASA in FDM, or protect the part with a UV-resistant coating.
Is SLA more expensive than FDM?
Usually, for a part of the same volume, because resin costs more and parts need washing and curing. The detail and surface finish can save finishing time later.
Get started
Talk to an engineer about your part.
Send us your CAD or describe the problem. We recommend the process, material and finish, and quote with the lead time up front.
Uploads are secure and confidential