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July 24, 2002 — Call it serendipity. Call it luck. Call it the convergence of microsystems and dental floss.
Some of the greatest business breakthroughs have come when designers applied a process from one realm into another. That’s kind of how it went at North Carolina development firm MCNC which, in conjunction with synthetic fiber specialists Hills Inc., just made microactuators out of synthetic polymers.
In other words, a MEMS-type device out of the same process that makes fishing line, carpet and dental floss.
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Known as integrated force arrays (IFAs), the microactuators combine a trio of polymers that contract when electricity is applied, similar to a shape memory alloy. They are manufactured using polymer extrusion, which transforms plastic pellets into long ribbons at up to 200 meters per minute. Hills, based in West Melbourne, Fla., said the actuators, cut from the ribbons, contain features as small as 0.5 microns and says 0.3-micron features are possible.
“It’s like a weed whacker line with a machine embedded down the core,” said Jeff Haggard, Hills’ vice president of technology.
Making the connection between a product and process isn’t enough, however. If polymer microsystems are going to make it into market, they’ll need to offer additional features or a lower price, and meet a compelling need.
In this case, the price may be most convincing. Haggard said he could produce the actuators for $1 to $2 per pound, each pound yielding between 100,000 and 300,000 units.
“What’s exciting about this is the potential price model,” said Marlene Bourne, a MEMS analyst with In-Stat/MDR. “You can have a great technology that can be made unbelievably cheaply.”
It is also easily handled. “This method has the advantage in packaging … because … you’ve got a strand you can handle by hand,” Haggard said. Scott Goodwin-Johannson a researcher in the materials and electronic technologies division at MCNC, said the “actual elements are coated by an insulating film,” and the microactuators could be exposed.
However, even if that works, the cost of assembly must still be taken into account, and at this point it’s an unknown.
“You should take a step back because you don’t know how this would be packaged,” Bourne cautioned, adding that packaging and assembly could add several dollars to each device. “That’s the hurdle right there.”
Finding the killer application that would draw polymer microsystems into market is a potentially larger hurdle.
IFAs were originally the work of Stephen Bobbio, formerly of MCNC and now a professor in the department of electrical and computer engineering at the University of North Carolina at Charlotte.
The initial application was robotics, one that demands actuators that stack and overlap, like a muscle. “Just look at any articulated joint,” Goodwin-Johannson said. “You have to support all that weight.”
In addition to being cheaper, the polymer microactuators are also lighter and stackable. The more that are stacked, the stronger the actuator becomes. MCNC also sees applications in microrobotic surgical tools and tactile displays.
Whether or not any of these applications can create the kind of market pressure necessary to make polymer microsystems a hit remains to be seen.
In the meantime, the technology faces a more mundane challenge. The project, originally funded by the Defense Advanced Research Projects Agency (DARPA), recently completed a yearlong initial development phase. Now MCNC and Hills are scouting for more DARPA funding or another agency or company that wants to take it the next step.