Californian research facility Lawrence Livermore National Laboratory (LLNL) has made a breakthrough with 3D printed transparent glass.
LLNL, in conjunction with the University of Minnesota and Oklahoma State University, has developed the innovative process using of silica particles. Similarly, recent research stemming from Germany has created glass 3D printed structures using stereolithography. However, this new approach from LLNL involves a direct writing of the material. The LLNL believe the breakthrough could expand the design of lasers and other optical devices.
Luxexcel, based in Belgium, is also demonstrating the use of 3D printing to create lenses. The company has recently gained certification from ISO for their optical lenses which are 3D printed using acrylic.
You are getting very sleepy… ? as we 3D print a glass optic. ? ⬇️ pic.twitter.com/9ZPHCnVzyw
— LLNL (@Livermore_Lab) May 2, 2017
Glass particle inks
Citing the fact that other glass 3D printing efforts have primarily involved molten glass, LLNL explains that their method intended to move away from such techniques. This is because using molten glass often creates porous, uneven structures.
Instead, the LLNL researchers developed a glass particle ink which suspends silica particles in a fluid allowing the material to be 3D printed at room temperature. The material is 3D printed using a direct-ink writing process and then given a heat treatment which results in a transparent lens.
LLNL materials engineer Du Nguyen explains the importance of this process as,
For printing high-quality optics, you shouldn’t be able to see any pores and lines, they have to be transparent. Most other groups that have printed glass melt the glass first and cool it down later, which has the potential for residual stress and cracking. Because we print at room temperature, that’s less of an issue.
LLNL has also used a direct-metal writing process to create metal 3D printed structures with recent research. The innovative method enables 3D printing to occur at room temperature which is a stark contrast to conventional laser-based metal 3D printing.
New applications for lenses
As chemical engineer and project lead Rebecca Dylla-Spears explains, the facility has been encouraged by these developments to extend the application of the materials.
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.
LLNL expects the 3D printing method to have application for microfluidic devices. Microfluidics is the study of fluids on a sub-microscopic scale and the use of 3D printed glass would be ideal in order to harness the material’s chemical resistance and transparency. 3D Printing Industry has seen recently how 3D printing has been used to create molds for microfluidic devices. LLNL explain that they wish to use the new technique for its expanded possibilities rather than to create similar optical devices.
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Featured image shows one of the 3D printed optics. Photo by Jason Laurea/LLNL.