[Techtaffy Newsdesk]

A technique inspired by pop-up books and origami will soon allow clones of robotic insects to be mass-produced by the sheet, says engineers at the School of Engineering and Applied Sciences (SEAS), Harvard University. Tiny robots can now be built by slightly bigger robots, using the technique, the layering and folding process enables the rapid fabrication of not just microrobots, but a broad range of electromechanical devices.

In prototypes, 18 layers of carbon fiber, Kapton (a plastic film), titanium, brass, ceramic, and adhesive sheets have been laminated together in a complex, laser-cut design. The structure incorporates flexible hinges that allow the three-dimensional product—just 2.4 millimeters tall—to assemble in one movement, like a pop-up book. The entire product is approximately the size of a U.S. quarter, and dozens of these microrobots could be fabricated in parallel on a single sheet.

The Harvard Office of Technology Development is now developing a strategy to commercialize this technology. As part of this effort, they have filed patent applications on this work and are engaging with entrepreneurs, venture capitalists, and companies to identify disruptive applications in a range of industries.

“This takes what is a craft, an artisanal process, and transforms it for automated mass production,” says Pratheev Sreetharan (A.B. ’06, S.M. ’10), who co-developed the technique with J. Peter Whitney. Both are doctoral candidates at the Harvard School of Engineering and Applied Sciences (SEAS). “Until recently, the manual assembly process was the state of the art in this field,” Mr. Sreetharan adds.

“Our new techniques allow us to use any material including polymers, metals, ceramics, and composites,” says principal investigator Rob Wood, an Associate Professor of Electrical Engineering at SEAS and a Core Faculty Member at the Wyss Institute for Biologically Inspired Engineering at Harvard.

“The ability to incorporate any type and number of material layers, along with integrated electronics, means that we can generate full systems in any three-dimensional shape,” Wood says. “We’ve also demonstrated that we can create self-assembling devices by including pre-stressed materials.”

The same mass-production technique could be used for high-power switching, optical systems, and other tightly integrated electromechanical devices that have parts on the scale of micrometers to centimeters. Moreover, the layering process builds on the manufacturing process currently used to make printed circuit boards, which means that the tools for creating large sheets of pop-up devices are common and abundant. It also means that the integration of electrical components is a natural extension of the fabrication process—particularly important for the size- and weight-constrained RoboBees project.

Designing how all of the layers will fit together and fold, however, is still a very human task, requiring creativity and expertise. Standard computer-aided design (CAD) tools, typically intended for either flat, layered circuit boards or 3D objects, do not yet support devices that combine both. Once the design is complete, though, fabrication can be fully automated, with accuracy and precision limited only by the machining tools and materials.

The work was supported by the U.S. Army Research Laboratory, the National Science Foundation (through the Expeditions in Computing program), and the Wyss Institute.