Making glass objects using additive methods is not easy, which is why only two groups of researchers have so far succeeded in this task – one did so by printing molten glass, which requires high temperatures and heat-resistant equipment, while the other printed ceramic particles which can be transformed into glass later, but lack any real degree of complexity.
Thanks to researchers from ETH Zurich, however, this might soon change. Using stereolithography – one of the first 3D-printing methods developed back in the 1980s – a team led by André Studart from ETH have come up with a special, plastic-enriched, resin, and organic molecules to which glass precursors are bonded.
“The digital fabrication of oxide glasses by three-dimensional (3D) printing represents a major paradigm shift in the way glasses are designed and manufactured, opening opportunities to explore functionalities inaccessible by current technologies”, wrote the researchers in their paper.
The technique consists of irradiating the polymer resin with UV light, thereby causing its light sensitive components to cross link and harden – plastic monomers combine to form a labyrinth-like structure and the ceramic-bearing molecules fill in the gaps.
Since the object is built layer-by-layer, researchers can control the pore size of each layer by adjusting the intensity of the light (weak light results in large pores and vice versa) – a feature which they have discovered completely by accident.
In addition, the technique allows complex objects to be made from different types of glass – or even by combining several types within a single object – by mixing silica with borate or phosphate and adding it to the resin.
Once the desired object is finished, it is first exposed to a temperature of 600˚C to burn off the polymer framework and then to around 1,000˚C to transform the ceramic structure into hard, transparent glass similar of window glass.
Even though this technique cannot be used to produce objects much larger than a die, the researchers have already applied for a patent and are currently negotiating with a Swiss glassware dealer for commercial deployment.
“Because most functional properties of glasses emerge from their transparency and multicomponent nature, this 3D printing platform may be useful for distinct technologies, sciences and arts.”
A paper detailing the new technique was published in the latest issue of the journal Nature Materials.