Researchers at Lawrence Livermore National Laboratory have developed a way to 3D print glass at room temperature. It could have a huge impact on optics fabrication.
If you want to 3D print glass, the temperature an extrusion nozzle has to endure is 1,900 degrees Fahrenheit (1030 degrees Celsius). 3D printing glass a rewarding, but an extremely complicated process and requires special equipment – up until now. Lawrence Livermore National Laboratory researchers have developed a process for efficiently 3D printing glass at room temperature.
The US researchers believe that this development could make a large impact on the design of devices which use optics, such as lasers. To allow for this synthesis, they used a “slurry” of silica particles extruded through a direct-ink writing process.
Also, Karlsruhe Institute of Technology recently developed a method for 3D printing clear glass using a consumer stereolithography printer. However, both groups of researchers have developed a method which doesn’t rely on printing molten glass.
In fact, LLNL’s process is 3D printed at room temperature. To make this happen, they also worked with scientists from the University of Minnesota and Oklahoma State University. Rebecca Dylla-Spears is an LLNL chemical engineer and project lead. She explains:
“The Lab is always looking for different ways to create new materials for optical applications… We’re not going to replace the optical materials made through traditional means, but we’re trying to impart new functionality using additive manufacturing. This is the first step to being able to print compositionally graded glass optics.”
The Benefits of 3D Printing with Glass
It’s previously been impossible to achieve glass structures and composition gradients using traditional additive manufacturing processes. Instead, the new method sees a process which relies on creating custom 3D printing inks. These are developed from “concentrated suspensions of glass particles with highly controlled flow properties.” This means the researchers can print them at room temperature, making it much easier to handle.
At first, the printed object is opaque. However, this quickly changes with drying and heat treatments. After printing, the objects receive a thermal treatment. The purpose of this is to densify the parts and in the process, removing any printing indications.
The final step is for the object to be polished to optical quality. By doing this, the object is more likely to achieve optical uniformity.
Tayyab Suratwala, LLNL’s program director for Optics and Material Science and Technology, explains some of the benefits of this process, saying:
“Optical fabrication research and development is trending toward freeform optics, which are optics that can be made virtually to any complex shape… Expanding this to 3D-printed optics with compositional variation can greatly increase the capabilities of this new frontier.”
The researchers also point out that, as well as expanding optical options, this process could also be beneficial for microfluidic devices. Want to find out more? You can read over the paper in Advanced Materials here. Here‘s an excerpt:
Silica inks are developed, which may be 3D printed and thermally processed to produce optically transparent glass structures with sub-millimeter features in forms ranging from scaffolds to monoliths. The inks are composed of silica powder suspended in a liquid and are printed using direct ink writing. The printed structures are then dried and sintered at temperatures well below the silica melting point to form amorphous, solid, transparent glass structures. This technique enables the mold-free formation of transparent glass structures previously inaccessible using conventional glass fabrication processes.
