Miniature manufacturing processes were once solely the territory of Swiss watch makers, hand assembling tiny machines with precision. These types of manufacturing processes has never transferred well to mass production, until now.
A team of Harvard scientists have taken micro sized mass production in a whole new direction. Inspired by origami and fold out books the team has developed an incredible micro machine that requires almost zero human assembly. The Mobee is the first example of such a manufacturing process, a tiny collection of sub millimeter parts that self-assemble into miniature robotic Bee.
“This takes what is a craft, an artisan 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).
Pop-up Fabrication of the Harvard Monolithic Bee (Mobee)
The ground-breaking manufacturing process is like flat pack manufacturing for robots. Initially all parts are laid out in a similar way to the production of computer chips with layer upon layer fabricated. Then the completed flat structure is laser cut to produce the separated parts. With 20 folding points the Mobee pops up into its final shape. While the production process and pop-up book assembly are nothing new the design that allows all of this to happen is very unique. Not only do the designers need to create all of the parts but the design must include the pop up mechanism. Most of the hard work in this case is done during the design process not the assembly process, as is traditional.
One of the secrets to the process is the assembly scaffold that controls the folding process, it is discarded once Mobee is complete. Designed and manufactured as part of the Mobee initially the scaffold makes sure the Mobees parts all move and fold into position correctly. Once the Mobee is in its final shape it is soldered – dipped in solder bath – and then laser cut to separate it from the scaffold.
While tradition manufacturing process work well for human sized objects assembling objects as small – sub-millimeter scale – as the Mobee has always been extremely difficult. Mobee is assembly free manufacture at its best. Traditionally manufacturing something like the Mobee would have required all of the parts to be manufactured separately and then assembled by hand. The assembly process itself is often responsible for a high failure rate of the final product. At these sizes traditional assembly techniques require microscopes and a very steady hand. Assembly is also one of the more expensive parts of the manufacturing process, it is very labour intensive.
In the Mobee’s case most of the manufacturing work is done during the layering process. Each of the 18 layer consists of various materials that form the folding body and internal circuits of the Mobee. The layers themselves are made of a combination of carbon fibre, titanium, brass and a plastic called Kapton, all laminated together. At the moment the only human involvement required in the manufacturing process is the attaching of the wings.
The completed Mobee integrates circuits and electric actuators, motors, this isn’t just a demonstration This becomes obvious when applying a voltage to the Mobee which causes it to flap it’s wings at various speeds.
There are still a number of advancements required before the Mobee becomes a truly autonomous insect, batteries and controller circuits still need to shrink dramatically to fit into and power the Mobee during flight. Still a most impressive example of thinking outside of the box. Let the insect wars begin.