Lost Ice Casting: Researchers 3D Print Ice to Build Complex Internal Microchannels

Researchers from Carnegie Mellon University have developed a novel way to create intricate and complex microstructures using 3D printed ice. While it’s true that this technology is still being developed, once matured, it could pave the road for many advances in biomedical engineering, manufacturing, and art.

3D Printed Ice

The group, led by Akash Garg and Dr. Saigopalakrishna Yerneni, a Ph.D. student and a postdoc at the university respectively, sought to solve a large problem affecting tissue engineers and fluid dynamic researchers: how do you create complex internal structures with current technology? The solution? “Inside-out” 3D printing.

Their method, as detailed in the journal Advanced Science, essentially uses an inkjet printer that extrudes water as the “ink,” which turns directly to ice, then encases that print in resin. Once encased, the water is removed leaving a pathway where the ice once stood.

Diagram of the group’s printing process from print to final channel. (Source: Carnegie Mellon University)

Specifically, the printer drops water droplets onto a custom-built, temperature-controlled platform that instantly freezes the water into ice. By modulating the speed and the movements of the printer with the -35°C build plate, the scientists were able to print a variety of structures including trees, helixes around a pole, and even an octopus. The structures have extremely smooth features and can be adjusted in diameter continuously.

Picture of freeform 3D printed ice structures. (Source: Carnegie Mellon University)

After printing, the team needed to ensure their efficacy as sacrificial structures, and attempted to cast the ice in Henkel Loctite resin. While the first few attempts were unsuccessful, they did find a method to remove the ice and leave the ultrasmooth internal structures behind with only a 3 µm deviation from what was expected.

Implications for Microfluidics

The scientists boast this method’s benefits of not only easy-to-remove internal structure after casting via melting or sublimation, but also the inherent biocompatibility that comes with using water. They hope that this work will aid any researcher who needs to create microstructures and complex channels such as tissue engineering or microfluidics.

If Akash and Dr. Terneni can continue to develop their process, it could be a game changer in the additive space. While this isn’t the first ice 3D printer that has been developed, the method created by Carnegie Mellon has shown to be a faster and more reliable ice 3D printing method when compared to other ice 3d printers. As the need for smaller and more intricate channels grows, this method could provide a viable solution to that field—especially if it helps solve one of the biggest issues in creating the small channels: removing the material afterward.