Transparent and dense BPS glasses obtained by sintering 3D printed porous objects.

A 3D printer sculpted these complex glass structures. Credit: Dr Kunal Masania/ETH Zürich

Materials science

Move aside, plastic: 3D printing conquers glass

Technique produces an array of transparent objects, including a glass leaf with delicate veins.

A standard 3D printer fed with an innovative mixture of ingredients can print intricate glass shapes — without extruding molten glass.

Glass normally needs to be heated to more than 1000°C to be shaped. To avoid such searing temperatures during printing, Kunal Masania, André Studart and their colleagues at the Swiss Federal Institute of Technology in Zurich developed a glass recipe that includes inorganic glass precursors and light-responsive organic compounds. This mixture is added to a standard 3D printer that uses light to solidify liquid inks.

During printing, light triggers the organic compounds to link into long chains, or polymers, which in turn causes the glass precursors to migrate to polymer-free regions.

The printed structure is then baked to burn off the organic polymer, leaving a porous material made of only inorganic compounds. A final step removes the air trapped in the pores, compacting the object and completing its transformation from an opaque ceramic to a transparent glass.

The authors used the process to create various complex shapes, including a leaf (pictured) with elaborate veins.

An erbium–ytterbium doped glass composition printed on top of the main body along the primary veins of the leaf.

Credit: D.G. Moore et al./Nature Mater.