SLA is fomous for being the original 3D printing technology. The process uses mirrors, known as galvanometers or galvos, (one on the x-asis and one on the y-asis) to rapidly aim a laser beam across a vat, the print area, curing and solidifying resin as it goes along. This process breaks down the design, layer by layer, into a series of points and lines that given to the galvos as a set of coordinates. Most SLA machines use a solid state laser to cure parts.
Bottom - up (Desktop) SLA
Top - down (Industrial) SLA
If parts of very high accuracy or smooth surface finish are needed, SLA is the most cost-effective 3D printing technology available. Best results are achieved when the designer takes advantage of the benefits and limitations of the manufacturing process.