Take a look at this amazing fabrication process that can be used to make the latest flying robotic insects, as well as other tiny 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.
"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).
The Harvard Monolithic Bee is a millimeter-scale flapping wing robotic insect produced using Printed Circuit MEMS (PC-MEMS) techniques. This video describes the manufacturing process, including pop-up book inspired assembly.
(Pop-up Fabrication of the Harvard Monolithic Bee)
"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."
Pointing to the carbon-fiber box truss that constitutes the pop-up bee's body frame, Sreetharan says, "Now, I can put chips all over that. I can build in sensors and control actuators."
Essentially, tiny robots can now be built by slightly bigger robots.
Their ultimate goal seems the same as that of the protagonist in The Scarab, a 1936 science fiction story by Raymond Z. Gallun. In the story, the Scarab - a tiny robotic insect - is used as a secret spy device:
"With the Scarab as big as a beetle, I could make a Scarab as big as a sand grain. This second Scarab could build a miniature of itself, as big as a dust grain. The third Scarab could construct a fourth, bearing the same proportions as the first to the second, or the second to the third. And so on, down, to the limit imposed by the ultimate indivisibility of the atoms themselves."
(Read more about micro-robot fabrication)