This 3D Printer Is a Real Glass Act

Silica glass, also known as fused silica or quartz glass, is a type of glass composed primarily of silicon dioxide. It is produced by melting high-purity silica sand or quartz crystals and then cooling the molten material to form a solid glass. This substance has some unique properties that make it indispensable for a number of applications.

It is highly transparent to visible light, which allows it to transmit light with minimal absorption or distortion. This makes silica glass ideal for use in producing high-quality lenses, windows, prisms, and optical fibers. This glass also has a very high melting point above 3,000 degrees Fahrenheit that make it well-suited for use in furnace windows, laboratory equipment, and aerospace components.

The multitude of useful applications requiring silica glass have given rise to an interest in manufacturing objects with this material via 3D printing. However, fabricating objects with features at the microscale level required for many interesting use cases has proven to be highly challenging. The stability and the brittleness of silica glass makes it difficult to work with, and necessitates the introduction of complex and energy-intensive procedures like sintering the glass at over 2,200 degrees Fahrenheit. Moreover, such processes can introduce impurities and other defects into the printed objects.

A simpler method of 3D printing glass objects with microscale resolution has recently been described that promises to make the fabrication of high-quality optics, and other objects, much more practical. The team, led by researchers at the KTH Royal Institute of Technology in Sweden have eliminated the need for high-temperature sintering with their novel approach. Using this technology, the researchers have 3D printed glass objects that are smaller and more detailed than was previously possible.

The key to the team’s success is a process in which hydrogen silsesquioxane is locally crosslinked to silica glass using nonlinear absorption of laser pulses less than one billionth of a second in duration. This produces an optically transparent glass, but not necessarily pure enough for all applications due to the presence of 4-membered silicon-oxygen rings and photoluminescence. Where such purity is required, an optional annealing step can be added to the process that will render the final product indistinguishable from pure fused silica.

This breakthrough technology allows for 3D glass printing to be used in practical scenarios, and using commercial materials that are readily available. To demonstrate their methods, the team 3D printed the world’s smallest wineglass, which has a rim smaller than the width of a human hair. Such a glass could be just what you are looking for if you are craving a few nanoliters of wine. But in all seriousness, the wineglass was printed to demonstrate the system’s capabilities, not for any utility that the glass itself could offer — perhaps the team simply did not want to 3D print yet another Pokémon character to sit on their desks?

On a more practical note, a tiny optical resonator was also printed, showing how useful parts for applications like fiber optic telecommunications can also be produced on demand. The work done by this group is a huge leap forward in the field, and the researchers expect that it will simplify the fabrication of many technologies. They are also exploring ways to add additional functionalities to objects printed with their system. They suggest that adding nanodiamonds to the mixture might enable hybrid quantum photonics integration, for example. Another idea being explored is the addition of ferrous nanoparticles to achieve magnetic remote control of printed items.