Stereolithography

A 3D-printing process that cures liquid resin into solid plastic layers using ultraviolet light.

• The resin contains molecules that link into a solid plastic network wherever UV light strikes them.
• A laser traces, or a projector or screen flashes, each layer's shape; the build platform then moves one layer and repeats.
• Layers of 25–100 micrometres give smooth, detailed parts, used for dental aligner moulds, hearing aids and prototypes.
• Parts need washing and a final UV cure, and many resins are more brittle or heat-sensitive than injection-moulded plastics.