How It Works
(SLA or SL; also known as stereolithography apparatus, optical fabrication, photo-solidification, or resin printing)
Stereolithography is an additive manufacturing process that works by focusing an ultraviolet (UV) laser on to a vat of photopolymer resin. With the help of computer aided manufacturing or computer aided design software (CAM/CAD), the UV laser is used to draw a pre-programmed design or shape on to the surface of the photopolymer vat. Because photopolymers are photosensitive under ultraviolet light, the resin is solidified and forms a single layer of the desired 3D object. This process is repeated for each layer of the design until the 3D object is complete.
In models featuring an elevator apparatus,  an elevator platform descends a distance equal to the thickness of a single layer of the design (typically 0.05 mm to 0.15 mm) into the photopolymer vat. Then, a resin-filled blade sweeps across a cross section of the layer, re-coating it with fresh material. The subsequent layer is traced, joining the previous layer. A complete 3D object can be formed using this process. Designs are then immersed in a chemical bath in order to remove any excess resin and cured in an ultraviolet oven.