The resins used for the SLA process are composed of two basic parts. The first is a photoinitiator which absorbs laser energy to start a chemical reaction which begins the polymerization process. The second part is a polymer which hardens after reacting with the photoinitiator. Certain polymers also contain thermoset materials which allow the finished part to harden with the introduction of heat.

These resins are usually either epoxy based (which tends to be stronger but also more expensive) or acrylate-based. There have also been recent developments which incorporate ceramics into the epoxy resin, making it far stronger, and much more useful for various tests.

Click here for material properties of some common resins.