Resin 3D printing is the process of curing a liquid plastic with light. It’s one of the oldest forms of 3D printing and still produces some of the best quality prints with an unmatched level of detail. While an array of technologies and machines are utilized in resin printing, two of the main ones are stereolithography (SLA) and digital light processing (DLP). These two types achieve the same goal in different ways. Simply put, the main difference is that SLA uses a laser light source to cure the resin, while DLP uses a projection system with LED lights

Among 3D printing processes, SLA and DLP are typically seen as the technologies capable of reaching the highest standards in terms of part complexity and precision. Both rely on the use of light, typically in the UV region of the spectrum (365-405 nm), although some printers use visible light to cure the photosensitive resin. In simple terms, the laser or projector draws an image in the resin that makes the liquid harden. Before we talk about how the resin is cured, it’s worth discussing what resin is.3D printing resin is typically composed of epoxy or acrylic and methacrylic monomers that polymerize and harden when exposed to light. This process is called cross-linking. As light shines on the resin vat to create specific shapes or patterns that make up each layer, a solid object is built up. Depending on the particular resin, its characteristics can vary greatly from soft and rubbery to very hard or high-temperature materials.