In addition to plastic, metal or ceramics, numerous other materials are now available for 3D printing. Glass is one of these supposedly exotic 3D printing materials. We have therefore put together some important information about glass 3D printing for you.
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Various methods of glass 3D printing
In order to be able to process glass additively, researchers have recently developed two different processes.
glass melt
One way is via the glass melt. This process was developed at the Massachusetts Institute of Technology (MIT) in Cambridge, USA, and introduced in 2016. Here, the glass is melted in a chamber of the 3D printer at over 1000°C. In a second chamber with an integrated pressure unit, the molten glass is formed according to the structures specified in the CAD files. At room temperature, the glass finally cools down in the structures formed in this way. However, these are sometimes very sharp-edged, which is why manual post-processing is sometimes necessary.
From plastic to glass
Since 2019 it has also been possible to manufacture glass objects directly from photopolymer materials. There are now 2 different methods for this.
A research team from ETH Zurich led by David Moore, Lorenzo Barbera and Kunal Masania from the Complex Materials group developed a special resin for this purpose, which is composed of a liquid plastic and a siloxane (i.e. a special silicone). With the help of a conventional SLA (stereolithography) printer, this resin is now cured by irradiation with UV light in the sense of the desired structures. Here it is possible to change various parameters. Weak light intensity creates large pores, while strong radiation creates small pores, which the ETH researchers initially discovered by accident. The microstructure of the object can also be influenced by adding borate or phosphate. In this way, objects can be built from different types of glass.
Material mix instead of resin
The process, which a research team led by Bastian Rapp and Frederik Kotz from the NeptunLab at the University of Freiburg, together with researchers from the Karlsruhe Institute of Technology, also brought to market maturity in 2019, relies not on a special resin, but on a plastic-quartz mixture. This is a light-sensitive composite material in which tiny quartz glass beads are evenly distributed like in a matrix. The printing process itself then runs through an intermediate step: the plastic matrix decomposes at 600°C, with the result that the remaining quartz glass powder is evenly packed at 1300°C. The structures of the planned object that have already been printed in the material mix are “taken over” into the remaining, pure quartz glass body, since the melting process takes place evenly in all spatial directions.
Glass using the FDM process
French researchers from the ICMCB-CNRS laboratory and the University of Bordeaux presented a way to print glass using the FDM process to the public in 2020. To do this, they developed a special glass filament made from basic phosphate. This material was created in a crucible at 800°C and drawn into a 1.9 mm thick bar. In principle, the filament obtained in this way can now be processed with a conventional FDM printer, albeit at exceptionally high temperatures of 470°C nozzle and 320°C print bed temperature. In this way, the 3D printing of state-of-the-art optical components and new biomedical devices should be made possible.
Read more about innovative 3D printing materials and processes on our 3D Activation blog.