Researchers from the Massachusetts Institute of Technology and the University of Texas at Austin have demonstrated the first chip-based resin 3D printer. Their proof-of-concept gadget is made up of a single millimetre-scale photonic chip that emits programmable light beams into a resin well, which cures into a solid structure when exposed to light.
The prototype processor has no moving parts and instead uses an array of small optical antennae to steer a beam of light. The beam projects up into a liquid resin that has been engineered to cure quickly when exposed to the beam’s visible light wavelength.
By integrating silicon photonics and photochemistry, the interdisciplinary research team was able to show a chip capable of steering light beams to 3D print arbitrary two-dimensional designs, including the letters M-I-T. Shapes can be completely constructed in a few of seconds.
Silicon Photonics & Specialised Resins
The Notaros group, which specialises in silicon photonics, created integrated optical-phased-array devices that guided light beams using microscale antennas on a chip. They may change the optical signal on either side of the antenna array to steer the light beam. These systems were critical for lidar sensors, which surveyed their surroundings using infrared light. Recently, the group has moved its focus to devices that produce and steer visible light for augmented-reality applications.
Around the same time they began brainstorming, the Page Group at UT Austin developed specialised resins that can be swiftly cured utilising visible light wavelengths for the first time. This was the missing piece that made the chip-based 3D printer a reality.
“With photocurable resins, it is very hard to get them to cure all the way up at infrared wavelengths, which is where integrated optical-phased-array systems were operating in the past for lidar.”
– Sabrina Corsetti, lead author and EECS graduate student
Corsetti added, “Here, we are meeting in the middle between standard photochemistry and silicon photonics by using visible-light-curable resins and visible-light-emitting chips to create this chip-based 3D printer. You have this merging of two technologies into a completely new idea.”
Chip-based Resin 3D Printer
Their prototype consists of a single photonic chip with an array of 160-nanometer optical antennas. (A sheet of paper is approximately 100,000 nanometers thick.) The entire chip fits on a US quarter.
When driven by an off-chip laser, the antennas direct a steerable beam of visible light into the photocurable resin well. The chip sits beneath a clear slide, similar to those used in microscopes, which has a small depression that traps the resin. The researchers utilise electrical impulses to direct the laser beam in a nonmechanical way, allowing the resin to harden wherever it strikes.
“This system is completely rethinking what a 3D printer is. It is no longer a big box sitting on a bench in a lab creating objects, but something that is handheld and portable. It is exciting to think about the new applications that could come out of this and how the field of 3D printing could change.”
– Jelena Notaros, Senior author, Robert J. Shillman Career Development Professor in Electrical Engineering and Computer Science (EECS)
The Page Group at UT Austin collaborated closely with the Notaros Group at MIT, fine-tuning chemical combinations and concentrations to achieve a formula with a long shelf life and quick cure.
Finally, the scientists demonstrated that their prototype could 3D print any two-dimensional shapes in seconds.
Future Prospects
In the long run, the researchers foresee a system in which a photonic chip lies at the bottom of a resin well and creates a 3D hologram of visible light, thereby curing a complete object in a single step.
This type of portable 3D printer could have a wide range of applications, including allowing physicians to build custom medical device components and engineers to create rapid prototypes on the job site.
Notaros is joined on the paper by Sabrina Corsetti, lead author and EECS graduate student; Milica Notaros, PhD ’23; Tal Sneh, an EECS graduate student; Alex Safford, a recent UT Austin graduate; and Zak Page, an assistant professor in the Department of Chemical Engineering at UT Austin. The findings are published today in Nature Light Science and Applications.
This research was supported in part by the National Science Foundation, the Defence Advanced Research Projects Agency, the Robert A. Welch Foundation, the MIT Rolf G. Locher Endowed Fellowship, and the MIT Frederick and Barbara Cronin Fellowship.
