3D printed letter M

This resin model of the University of Michigan emblem was printed in just one minute. Credit: Evan Dougherty

Technology

3D printing gets a lift from light

A sophisticated technique can make complex objects in a single shot by blasting resin with two wavelengths of light.

A fresh approach to stereolithographic printing has increased both the speed and reliability of this means of fabricating three-dimensional objects.

Stereolithographic printing builds each layer of a 3D object by projecting light through a window at the bottom of a vat of liquid resin. The light causes the resin to cure and solidify.

Mark Burns, Timothy Scott and their colleagues at the University of Michigan in Ann Arbor developed a method that uses two light sources — one to solidify the resin, and a separate ultraviolet light to prevent resin from curing on the window’s surface. The presence of a zone where no unwanted solidification occurred allowed for efficient use of resins and boosted the speed of printing: objects such as embossed text a fraction of a millimetre across could be created in a single exposure, rather than layer-by-layer, as with conventional methods.

The combined use of two colours of light in 3D printing could be further expanded to create complex objects that integrate materials with different chemical and physical properties, the authors propose.