Objects fabricated in 45-60 seconds from thiol-ene resins.

A ‘diamond ring’ can be fabricated in 45-60 seconds by shining beams of light on a vat of specialized resin. Credit: C.C. Cook et al./Adv. Mater.

Materials science

A promising 3D-printing method gets flexible

New ingredients allow a printing technique that once produced only brittle objects to turn out items that are pliable or sturdy.

From a vat of liquid resin, a 3D-printed ballerina emerges mid-pirouette in one smooth piece. Thanks to the liquid resin’s versatility, new dancers joining her could be either stiff and tough, or bendy and stretchy.

Volumetric additive manufacturing is an emerging approach to photopolymer-based 3D printing.

Researchers combined new raw ingredients and a 3D-printing method that builds objects all at once to create this figure of a dancer.Credit: C.C. Cook et al./Adv. Mater.

Most 3D-printing techniques gradually build up an object one thin layer of raw material at a time; finished products have a characteristic roughness. An alternative method prints objects by projecting multiple beams of light encoding the desired 3D shape into a resin inside a spinning vial, solidifying the desired form within minutes. But so far this technique has worked only with resins that harden into objects that are as brittle as glass.

Maxim Shusteff at the Lawrence Livermore National Laboratory in California and his colleagues identified three suitable molecular building blocks and combined them into resins. By varying the ratio of these molecules in the resin, the team could create objects with a vast range of material properties.

Some printed objects could stretch to more than four times their length before breaking. Others were stronger than most high-performing engineering plastics used in planes and cars.