Ever since its conception, 3D printing has rocketed to success; this is easily attributable to the sheer amount of possibilities it holds. However, given that there are still challenges regarding how to use and market this technology for widespread, and preferably domestic consumer use, these possibilities are still just possibilities.
One of the main challenges 3D printers and makers faces is the current limitation of materials that can in fact be printed. Although the growth of the technology has allowed an expansion to various materials like plastic, paper and metal, there has been one notoriously difficult material to print: glass.
The main obstacle in this endeavor has been the incredibly high temperature needed to melt the glass consistently. The temperature needs to allow for the glass material to be fluid enough to be shaped but viscous enough to not fall into a homogenous lump.
Some printers have used a technique called sintering, which involves the usage of small particles of glass melded together at lower temperatures. The process, however, produces structurally weaker and visually cloudier glass — which is counter-productive, given the material's two main strengths being structural coherency and transparency.
Recently, however, professors and researchers at MIT's Media Lab have found a way to print glass that is both structurally strong and transparent to light. A high temperature system developed at MIT allows users to print computer-assisted designs of glass into the real thing, with little human intervention.
In its current version, the molten glass is loaded onto a hopper atop the device. The object's hopper and nozzle are the primary shaping tools and are maintained at a temperature of around 1,900 degrees Fahrenheit (which is considerably greater than the temperature used for 3D printing other materials).
The stream of glowing molten is beautiful to watch as it slips out from the nozzle and slowly solidifies — a video from MIT's Mediated Matter Group demonstrates just that:
Oxman and her team also had a difficult time keeping the filament of glass hot and versatile enough for each additional layer — different layers of glass heating and cooling at different times opened doors for various structural inconsistencies.
To counter this, the team produced three distinct components that independently heat the material to the necessary temperatures. These include the upper reservoir for the base of molten glass, the nozzle beneath the chamber and one even lower when the printed glass is shaped.
Neri Oxmen, assistant professor at the MIT Media Lab, acknowledged that the process of finding this solution was time consuming, especially given the nature of the material and its ability to exhibit any alterations to internal features on its surface.
For further research and refinement, Peter Houk — director of the MIT Glass Lab — cited the possibility of adding pressure the molding system. This could be accomplished with the use of a mechanical plunger or compressed gas to produce a more consistent flow, and, as a result, more uniform width to expel the filament of glass. There has also been limited testing on how color can be infused in this mix as well.
The research and preparation for the this new glass printing system has come out of an interdisciplinary approach, involving team members from MIT's Media Lab, the Department of Mechanical Engineering and the Department of Materials Science and Engineering.
