IT

SLA – Stereolithography

Stereolithography (SLA) is a 3D printing technology that solidifies photopolymer resins with a UV laser, offering very high surface definition and fine detail — ideal for aesthetic prototypes and master models.

SLA – Stereolithography

What Stereolithography is

SLA (Stereolithography) is a 3D printing technology that solidifies liquid photopolymer resin with a UV laser, tracing each layer point by point. It is the oldest additive technology — patented by Chuck Hull in 1986 — and belongs to the photopolymerisation family, the same as DLP. The key difference between the two lies in how the light reaches the resin. While DLP projects a whole image and solidifies the layer in one shot, SLA uses a laser beam steered by galvanometric mirrors that draws the outline and infill of the cross-section like a pen retracing a profile, curing the resin along its path. Most modern desktop machines use the inverted bottom-up configuration: the laser projects from below through the transparent base of the tank, and the platform rises upward, lifting the part.

Why choose it

SLA is chosen when finish and fidelity of detail matter more than pure speed. The laser’s focal point defines XY resolution continuously, without the pixel quantisation typical of a DLP projector: no “voxel” effect on the edges, cleaner contours and smoother surfaces. This is why SLA remains the reference standard for very-high-fidelity applications. The trade-off is time. Because the laser traces point by point, the duration of a layer depends on how much area it has to cover, whereas in DLP it is constant because everything is flashed at once: for small, isolated parts the two technologies are comparable, but on dense layers or plates full of parts DLP is faster. When the goal is surface quality, however, SLA remains the better choice.

Typical applications

SLA is at its best where fine detail and a refined aesthetic finish are needed. Its natural fields are dentistry (models and guides), jewellery and patterns for lost-wax casting, aesthetic prototypes and presentation models, and masters for making silicone moulds. In general, any context where geometric fidelity and surface cleanliness matter more than mechanical strength or production speed.

Printable materials

ABS-like – White
ABS-like – WhiteWhite ABS-like is a photopolymer resin for SLA printing with ABS-like characteristics: good mechanical strength and rigidity, smooth surfaces and precise detail, for functional prototypes and technical components.
ABS-like – Clear
ABS-like – ClearClear ABS-like is a photopolymer resin for SLA printing that combines transparency with ABS-like mechanical characteristics: ideal for aesthetic applications and parts requiring a transparent effect without sacrificing solidity.

FAQ

When should you choose SLA?

When you need smooth surfaces and very fine detail, for example for aesthetic prototypes, presentation models or masters for silicone moulds.

What post-processing does an SLA part require?

Always some. Straight out of the machine the part is covered in liquid resin and must be washed in isopropyl alcohol (or a dedicated cleaner), then dried and post-cured under UV light to reach its final mechanical properties. Only then are the supports removed and the attachment points finished.

Which resins can be used and what are their limits?

There are standard resins for aesthetic prototypes, tough/durable resins closer to ABS, castable resins for lost-wax casting and specific technical resins. The common limit is that SLA parts remain more brittle than thermoplastics and tend to yellow and become brittle with prolonged UV exposure: they are ideal for prototypes and masters, less so for functional components meant for long sun exposure.

What dimensional accuracy and maximum size can you expect?

SLA is among the most accurate technologies: typical tolerances in the order of ±0.1–0.2 mm on small parts, with well-defined fine detail thanks to the laser's continuous focal point. The build volume depends on the machine; for parts larger than the platform, printing in several bonded pieces is used, which is helped by the process's dimensional stability.

Why choose SLA over FDM?

For finish and detail. FDM leaves layer-by-layer deposition lines and is better suited to economical functional parts; SLA starts from liquid resin and delivers smooth surfaces and fine geometries that FDM cannot achieve, at the cost of mandatory post-processing and a more brittle part.

Last updated: 10/06/2026