Digital light processing commonly known as DLP, which belongs to family of vat polymerization. Vat polymerization 3D printing technologies make use of a (liquid) photopolymer resin which is able to cure (solidify) under a light source.
In a DLP 3D printer, the light source is a specially developed digital light projector screen. The DLP projector screen flashes an image of a layer all at once! Thus, all points of a layer can be cured simultaneously.
The actual liquid itself is a thermosetting resin – that is, a resin that irreversibly and selectively turns solid in the presence of light. This chemical process results in very strong bonds, much stronger than those found in FDM-printed parts.