A new system from the Massachusetts Institute of Technology (MIT) creates strong, solid glass structures from computerized designs. The 3D-printing method allows researchers to construct optically transparent objects.

The glass 3-D printing process.
Credits:Photo: Steven Keating

Traditionally, glass is a difficult material to work with, given how its viscosity changes with temperature. Glass requires precise control of temperature at all stages of the process.

In the present version of MIT's device, molten glass is loaded into a hopper in the top of the device after being gathered from a conventional glassblowing kiln. When completed, the finished piece must be cut away from the moving platform on which it is assembled.

In operation, the device’s hopper, and a nozzle through which the glass is extruded to form an object, are maintained at temperatures of about 1,900 degrees Fahrenheit, far higher than the temperatures used for other 3D printing. The stream of glowing molten glass from the nozzle resembles honey as it coils onto a platform, cooling and hardening as it goes.

To protect structural integrity while enabling adhesion, the researchers produced three separate components that can independently be heated to the required temperatures: the upper reservoir for the stock of molten glass, the nozzle at the bottom of that chamber, and a lower chamber where the printed object is built up.

Components can be designed with variable thicknesses and complex inner features. Because glass is at once structural and transparent, researchers say it is easy to consider the integration of structural and environmental building performance within a single integrated building skin. Printed parts could also act as optical lenses.


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