The Complete Guide to Stereolithography (SLA) in 3D Printing

Stereolithography (SLA) is a 3D printing process that uses an ultraviolet (UV) laser to cure and harden liquid photopolymer resin, building objects one thin layer at a time. It belongs to the family of technologies known as vat photopolymerization, and is commonly referred to as resin 3D printing. Valued for its fine detail and smooth surface finish, SLA is widely used for prototyping and for producing casting patterns.

Stereolithography is one of the earliest 3D printing methods. The technology was patented in 1984 by Charles “Chuck” Hull, and the first commercial machine was developed by 3D Systems in 1988. Decades later, the technology remains a major force in the industry. The global stereolithography 3D printing market was estimated at USD 2.91 billion in 2025 and is expected to reach USD 21.98 billion by 2035, according to Spherical Insights.

A part from the Formlabs Form 4. (Photo Credit: Formlabs)

But how does it work? Find out below in our complete guide to stereolithography. For hardware recommendations, see our Top 10 resin 3D printers.