3-D printing of transparent glass is now possible

Researchers at MIT have demonstrated the first 3D printing technique able to make transparent glass objects.

The range of materials that 3D printers can work with has been steadily growing in recent years – from bioprinted cartilage constructs, to combinations ofdifferent plastic types in full colour, to elastic silicon membranes for heart attack patients, and even artificial rhino horn.

Some materials have been more difficult to develop, such as glass. Until now, it was only possible for opaque glass to be 3D printed. However, a team at the Massachusetts Institute of Technology (MIT) has achieved the first method for creating fully transparent glass, as demonstrated in this video.

The platform, known as "G3DP", is based on a dual-heated chamber concept. An upper chamber acts as a kiln cartridge, while the lower chamber serves to anneal the structures. The kiln cartridge operates at over 1,000°C (1900°F), with molten material being funnelled through a custom nozzle of alumina-zircon-silica. Objects are formed inside a third chamber, where they are cooled in a gradual, controlled way to ensure they don't break.

Finding a nozzle suitable for molten glass was a major challenge, according to the researchers. It had to be made of a material able to handle both high temperatures and resist the glass sticking to it. A paper describing their work, "Additive Manufacturing of Optically Transparent Glass", is available online.