Of all the "ink" used in 3D printing, "glass" is still one of the most problematic. Scientists at the Swiss research center ETH Zurich Research are working to create technology that will make these problems a thing of the past.
To date, there are several ways to 3D print glass objects - extruding molten glass and sintering ceramic powder using laser heating. However, in the first case, one has to deal with high temperatures, which requires heat-resistant equipment, and the second technology is not able to ensure printing of complex objects.
Swiss scientists propose using a photosensitive resin, consisting of a mixture of liquid plastic and organic molecules, to which, in turn, are attached silicon-containing molecules.
The resin is exposed to ultraviolet radiation in a process known as digital light processing. When light hits the resin, the plastic monomers are crosslinked to form a solid polymer with a labyrinth-like internal structure, with the space inside the labyrinth filled with ceramic molecules.
The resulting three-dimensional object is then fired at a temperature of 600 ° C, as a result of which the polymer is burnt, and the ceramic remains. Upon repeated firing, already at a temperature of about 1000 ° C, the ceramics are compacted, turning into transparent porous glass. During conversion to glass, the object decreases in volume, which must be taken into account when designing.
So far, we are talking about medium-sized objects, but at the same time of a rather complex shape. In addition, the technology allows you to adjust the pore size by changing the intensity of UV radiation. You can also change other characteristics of the object by mixing boric acid and phosphate salts into the resin. A large Swiss glassware manufacturer has already taken an interest in the technology.