Stereolithography
How Stereolithography
Acrylic or epoxy resins are used as the base material in SLA. These liquid resins are photoreactive, which means they react with UV rays and harden. Unlike many other additive manufacturing processes, stereolithography does not involve a classic layer application. The basic principle is that the build platform is placed in a tank filled with resin from above. This means that the components are printed upside down. For the first layer, the build platform moves all the way down and then up a layer thickness (0.1 mm). The liquid resin is distributed evenly underneath the building platform.
The UV laser now scans the component contours from below through a transparent membrane and cures the first layer. The platform then moves up again by 0.1 mm and the resin for the next layer can spread. This process is then repeated until all components have been printed. The build platform then moves completely out of the tank. This process also requires support structures to secure the component to the build platform. The finished printed components can now be removed, cleaned and removed from the supports. In stereolithography, several components can be produced simultaneously within a few hours using this principle.
Advantages of Stereolithography
In SLA, as in additive manufacturing in general, there are hardly any limits to component design. Undercuts can be implemented without any problems. Traditional problems and limitations from conventional manufacturing processes do not play a role. Stereolithography also has a number of advantages over other 3D printing technologies, which is why this process has been around for so long.

Precision and detail:
Very high level of precision and details
Maßhaltigkeit:
The mode of operation in combination with the curing plastic resin results in extremely dimensionally stable components. Even with larger components, the tolerances are comparatively extremely low.
Printable size:
In the SLA process, components up to a size of 2,000 x 1,000 x 1,000 mm can be manufactured in one piece. Components of this size can only be produced in one piece in very few processes.
Smooth surface:
The surfaces of components manufactured using stereolithography have a particularly smooth and high-quality surface. They can also be processed and polished quickly and easily.
Stereolithography: The Applications

Stereolithography is mainly used in rapid prototyping, i.e. in the creation of initial prototypes and functional or design samples. The ability to produce particularly large components is particularly popular in various sectors such as the automotive and aerospace industries. Thanks to the high-quality surface and uncomplicated post-processing, the SLA process is also usually the first choice for producing design samples or trade fair models.
One of the largest areas of application is vacuum casting. In vacuum casting, master models are used to create silicone molds from which cast parts are generated. These master models must be absolutely dimensionally accurate and have beautiful surfaces. For this reason, the stereolithography process is used almost exclusively for production.
Materials
Acrylic or epoxy resins are processed in the SLA. The cured resins have very good mechanical values. After thermal post-treatment, the components can even achieve a temperature resistance of over 220°C.
As the variety of materials is not so great and the individual materials are not usually very different from each other, a suitable material is usually selected for production. In terms of color, SLA components are usually white or gray, and there are also completely transparent materials.
Postprocessing SLA
Components produced using stereolithography can be ground and polished quickly and easily. Any surface finish can be achieved by surface treatment.
- Polish
- Varnishing
- Annealing
