Scientists 3d printing transparent glass
A research team at the Massachusetts Institute of Technology has succeeded in printing optically transparent glass with a 3D printer. The team managed to solve the problems surrounding high temperatures and glass strength.
The system for printing glass is described in a paper in the Journal of 3D Printing and Additive Manufacturing and was developed by scientists at MIT and several other universities. The system uses high temperatures to melt the glass, creates sufficient optical clarity and produces glass of sufficient strength.
Glass printing is not new, but is generally performed using sintering. During sintering, tiny glass spheres are fused together, but this does result in a porous and weak material. Also, the optical qualities of a sintered piece of glass are poor. The printed products of the MIT-ers are completely transparent for light and sturdy. The now presented version of the printer is fed with molten glass into a hopper after it comes out of a melting furnace. When the piece is finished, it must be cut free from the moving platform on which the product was formed.
The hopper and the spout where the molten glass comes out are both kept at a temperature of around 1100 degrees Celsius. At the end of the process, the product must be cut loose, just like with normal glass blowing. The glass comes out of the spout under the influence of gravity and looks like liquid honey when it comes out of the spout. The whole is printed on a platform to cool. The platform itself is also not cold: 480 °C. Maintaining the temperature of the glass that ends up on the platform is necessary to keep it hot enough to allow the different layers of glass to adhere well enough to each other.
With the device it is possible to print different glass thicknesses. Also, just like with ‘normal’ 3D printing, it is possible to make complex interior structures, something that is not possible with normal glassblowing. In the near future, experiments will be conducted with pushing the glass out under pressure, which will make it easier to control the flow of liquid glass. Testing has already been done with different colors of glass, but that too must be further refined in the future.