Revolutionary Robotic Glass-Blowing Techniques: Notre Dame Researchers Pioneer 3D Printing for Optical, Microfluidic, and Photonic Devices

A 3D printing method from researchers at the University of Notre Dame can deposit glass at 15 cubic millimeters per second.
Image credit: Wes Evard/College of Engineering, University of Notre Dame

Transforming Glass Manufacturing with Robotic Precision

For centuries, artisans have shaped glass into everything from household items to intricate windows. Today, researchers at the University of Notre Dame in Indiana are taking these age-old techniques to the next level by adapting them to a robotic platform. Using a laser and a computer-controlled stage instead of traditional tools like a torch and flame-resistant gloves, they are demonstrating how this innovative approach can create transparent solid structures needed for optical, microfluidic, and photonic devices.

Overcoming the Challenges of Glass in Additive Manufacturing

Silicate-based glasses are prized for their high thermal stability, stiffness, optical transparency, and chemical inertness, making them ideal for scientific equipment and consumer products. However, these same properties have traditionally made glass difficult to work with using additive manufacturing processes. High molten viscosity and glass's transparency across a broad range of wavelengths have presented significant obstacles, particularly in preventing bubble formation and achieving efficient absorption of laser energy in melt-and-solidify layering approaches.

Advancements in 3D Printing for Glass Structures

Ed Kinzel, an associate professor of aerospace and mechanical engineering at Notre Dame, aims to combine the geometric freedom of hand-blown glass with the precision of modern 3D printing. In his lab, a carbon dioxide laser locally melts small-diameter glass filaments, allowing them to be deformed and shaped into 3D structures. By moving a fused quartz substrate on a 4-axis CNC platform relative to the laser beam, the researchers can create intricate shapes by leveraging gravity, surface tension, and pneumatic pressure. This process has enabled the creation of both on-substrate 2D shapes and free-standing 3D spiral structures.

Improving Efficiency and Precision in Digital Glass Forming

Kinzel and his colleagues, including Luis Deutsch Garcia and Horacio Ahuett Garza from the Monterrey Institute of Technology and Higher Education in Mexico, have made significant progress in refining this 3D printing process. By carefully adjusting parameters like scan rate, laser power, and filament feed rates, they have moved from slowly printing hollow-tube structures to rapidly producing dense, perfectly transparent 3D solids. Their technique, which involves volumetric heating and the use of dopants to alter optical penetration depth, has shown promising results, with the ability to fabricate smooth, bubble-free 2D and 3D geometries at deposition rates of up to 15 cubic millimeters per second.

The 3D printing technique can make smooth, bubble-free glass in complex shapes.
Image credit: University of Notre Dame

Applications and Future Directions in Glass Manufacturing

The team has also demonstrated the potential of their approach for creating optical waveguides and is working toward developing photonic circuits. This groundbreaking work could revolutionize the production of free-form glass structures, which are typically limited to one-dimensional sheets or fibers. Kinzel believes that applications such as lightweight, high-strength lattices could greatly benefit from the unique properties of glass, offering significant advantages over traditional artisan methods.

Presentation and Publication of Research Findings

The researchers presented their findings at Optica’s Advanced Photonics conference in Quebec in July, and further details of their work were published in the June edition of the Journal of Manufacturing Processes. Their innovative approach to 3D printing with glass holds the potential to bridge the gap between traditional glass-blowing techniques and modern manufacturing technologies, opening up new possibilities for the creation of complex glass structures in various high-tech applications.

Article Source: IEEE Spectrum