Stereolithography (SLA) Technology
Stereolithography (SLA or SL) is an additive manufacturing or 3D printing technology used for producing models, prototypes, patterns, and production parts up one layer at a time by curing a photo-reactive resin with a UV laser or another similar power source.

SL: Quickly create complex Prototypes
Stereolithography is an established additive manufacturing process that can quickly and accurately create complex prototypes. Parts are built by curing paper-thin layers of liquid thermoset resin with an ultraviolet (UV) laser that draws on the surface of a resin to turn it from a liquid to solid layer. As each layer is completed, fresh, uncured resin is swept over the preceding layer and the process repeated until the part is finished.
Stereolithography: Minimal Stair Stepping
SL offers a range of plastic-like materials to choose from with several types of polypropylene and ABS available. Normal and high resolutions are achievable, meaning very fine details and cosmetic surfaces are possible. As a result, minimal “stair stepping” is seen compared to printed parts such as fused deposition modelling (FDM). SL parts can also be built to a max size of 736mm by 635mm by 533mm, giving it the edge over other additive processes like selective laser sintering (SLS).
The technology is also known as optical fabrication, photo-solidification, solid free-form fabrication, solid imaging and Resin printing technology.
Source: Wikipedia