Stereolithography is a generative rapid prototyping method in which plastic prototypes are manufactured from acrylic, epoxide or vinyl ether resins with a high degree of dimensional reliability and fine, smooth surfaces. A physical model of the prototype is created within a few hours directly from the 3D CAD data (STL format). In the SLA procedure, a UV laser beam is used to locally illuminate and harden the surface of a liquid photopolymer resin. This layering process is repeated until the entire geometry of the component is constructed. The finished model is then hardened and deburred. Components with complex geometries (undercuts, etc.) can be created by using this layered construction method. For overhangs, a support structure is required which is later removed.
Stereolithography is the oldest rapid prototyping method, and it is a mature, highly-precise and economical technology for creating design and function models. Stereolithography is the best method especially for small to medium-size prototypes requiring a high degree of precision and detail.