The researchers demonstrated this by printing a tree, a helix around a pole, and even a one-and-a-half-millimeter tall octopus figurine out of ice. Because of the water’s rapid phase change and the ice’s strength, freeform 3D printing of ice structures was possible without the need for time-consuming layer-by-layer printing or support structures.
“Controlling so many parameters was challenging,” explained Garg. “We gradually built up in complexity.”
Experiments were carried out to determine the printing path, motion-stage speed, and droplet frequencies required to fabricate smooth ice structures with straight, inclined, branching, and hierarchical geometries in a reproducible manner.
Burak Ozdoganlar, the associate director of the Engineering Research Accelerator at CMU, who oversaw the study, called it “an amazing accomplishment that will bring exciting advances.”
“We believe this approach has enormous potential to revolutionize tissue engineering and other fields, where miniature structures with complex channels are demanded, such as for microfluidics and soft-robotics.”
In as little as a year, the 3D ice process could be used for engineering applications such as creating pneumatic channels for soft robotics. However, clinical application for tissue engineering will take longer.
The study was first published in Advanced Science.
Water is one of the most important elements for life on earth. Water’s rapid phase-change ability along with its environmental and biological compatibility also makes it a unique structural material for 3D printing of ice structures reproducibly and accurately. This work introduces the freeform 3D ice printing (3D-ICE) process for high-speed and reproducible fabrication of ice structures with micro-scale resolution. Drop-on-demand deposition of water onto a −35 °C platform rapidly transforms water into ice. The dimension and geometry of the structures are critically controlled by droplet ejection frequency modulation and stage motions. The freeform approach obviates layer-by-layer construction and support structures, even for overhang geometries. Complex and overhang geometries, branched hierarchical structures with smooth transitions, circular cross-sections, smooth surfaces, and micro-scale features (as small as 50 µm) are demonstrated. As a sample application, the ice templates are used as sacrificial geometries to produce resin parts with well-defined internal features. This approach could bring exciting opportunities for microfluidics, biomedical devices, soft electronics, and art.