Vat polymerization is the process of curing a photopolymer, typically a liquid resin, using a UV light source. Vat polymerization systems on the market can be divided into two categories. There are laser-based systems and there are layer-based systems. The original technology, SLA, which stands for Stereolithography Apparatus is a laser-based system. DLP or Digital Light Processing and LCD or masked SLA are layer-based systems.
SLA – This technology “traces” the 2D cross section of each layer point by point using a high-power laser. This process will take longer to print as you add more objects to the build.
DLP – This technology projects UV light onto an entire cross-sectional layer of the resin. Since an entire layer is being cured at the same time, print times are faster regardless of the number of objects in the build.
LCD – This is similar to DLP in that an entire layer is cured at the same time but instead uses a UV LED array as a light source with an LCD that creates a digital “mask” during exposure of the photosensitive resin.