Among all the materials that can be 3D printed, glass is still one of the most challenging materials. However, scientists at the Research Center of the Swiss Federal Institute of Technology Zurich (ETH Zurich) are working to change this situation through a new and better glass printing technology.
It is now possible to print glass objects, and the most commonly used methods involve either extruding molten glass or selectively sintering (laser heating) ceramic powder to convert it into glass. The former requires high temperatures and therefore heat-resistant equipment, while the latter cannot produce particularly complex objects. ETH’s new technology aims to improve these two shortcomings.
It contains a photosensitive resin composed of liquid plastic and organic molecules bonded to silicon-containing molecules, in other words, they are ceramic molecules. Using an existing process called digital light processing, the resin is exposed to a pattern of ultraviolet light. No matter where the light hits the resin, the plastic monomer will cross-link to form a solid polymer. The polymer has a labyrinth-like internal structure, and the space in the labyrinth is filled with ceramic molecules.
The resulting three-dimensional object is then fired at a temperature of 600°C to burn off the polymer, leaving only the ceramic. In the second firing, the firing temperature is about 1000°C, and the ceramic is densified into transparent porous glass. The object does shrink significantly when it is transformed into glass, which is a factor that must be considered in the design process.
The researchers said that although the objects created so far are small, their shapes are quite complex. In addition, the pore size can be adjusted by changing the intensity of ultraviolet rays, or other properties of the glass can be changed by mixing borate or phosphate into the resin.
A major Swiss glassware distributor has already expressed interest in using the technology, which is somewhat similar to the technology being developed at the Karlsruhe Institute of Technology in Germany.
Post time: Dec-06-2021