Researchers for the first time have used 3-D printing to make a consumer electronic device, a loudspeaker ready for use almost as soon as it comes off the printer.

The work by roboticist Hod Lipson at Cornell University and his colleagues suggests 3-D printing might soon be mature enough to let people manufacture complete devices on demand.

"The exciting part of this project is that it paves the path to 3-D printing of consumer electronics and active systems," Apoorva Kiran, a Cornell mechanical engineer tells Txchnologist. "A good thing about 3-D printing inks that we developed at our lab is that even though they are for advanced applications, they are not hazardous chemicals, and their recipe is so simple that people can tinker with them even in their garage. With this work we hope that 3-D printing starts an era of open innovation."

Technology maturing
The world is seeing rapid advances in 3-D printers, which manufacture items from blueprints using a growing variety of ingredients — plastic, ceramic, glass, metal and even more unusual ingredients like sugar, mashed potatoes, chocolate and living cells. Such machines commonly work by laying down thin layers of material much like an ordinary printer, except they deposit layers on top of layers to create three-dimensional objects.

Increasingly, researchers are using hobby and industrial 3-D printers to make parts for complex devices such as robots and jet engines.

Loudspeakers are relatively simple devices typically made of plastic, conductive and magnetic parts. The Cornell researchers made their speaker from three components — a plastic housing, a conductive coil and a magnet.

To print the speaker, the researchers used a Fab@Home customizable research printer originally developed by Lipson and colleague Evan Malone. For the coil, they used conductive silver ink; for the magnet, they used a viscous blend of strontium ferrite; and for the housing, they used plastics typically extruded by 3-D printers.

"These speakers turn out to be relatively easy to print," says Robert MacCurdy, a Cornell electrical engineer.

For a demo, the researchers connected a freshly printed miniature speaker to amplifier wires and played a clip from President Barack Obama’s 2013 State of the Union address that mentioned 3-D printing.

"What’s personally exciting for us is the fact we used a consumer-scale 3-D printer in this way, so this work can pretty easily be replicated by others," MacCurdy says. He explained the Fab@Home chassis is a mishmash of different elements, including some from a commercially available MakerBot 3-D printer.

A studio and motors on the horizon 
The research team has used 3-D printing to make an electronic device before, albeit one not likely to find common use nowadays. They created a Vail Register, the antique telegraph receiver and recorder that Samuel Morse and Alfred Vail used to send the first Morse code telegraph. As a demonstration that the device worked, the researchers received and printed the same message Morse and Vail first transmitted in 1844 — “What hath God wrought.” 

In terms of future electronics that 3-D printers will be able to produce, MacCurdy says an obvious choice is a microphone, since the same components used for speakers can help create microphones.

"You can imagine a cool demonstration where you have this speaker-microphone that you’ve printed, hook it up to a microphone, and play back stuff you just recorded," MacCurdy says.

They’re already planning to print even more complex and interesting systems. The next step, MacCurdy says, “is to 3-D print a working electric motor, either AC or DC, with rotating parts.” Printing rotating parts is doable because “we’ve already seen how it is possible to 3-D print gears, and sometimes 3-D print entire working gear assemblies.”

"We hope to demonstrate 3-D printing of a self-powered system in a few years — a 3-D printed device with active moving parts and a 3-D printed power unit," Kiran says.

The researchers cautioned that it would still be a while before people are printing electronics at home. Current home 3-D printers cannot efficiently work with the multiple materials needed to make complex devices.

"Imagining that something really sophisticated like an iPhone could roll off a home 3-D printer would be totally fantastical — none of us are imagining that," MacCurdy says. "It’s not convenient enough to be a true high-volume, low-cost form of manufacturing, but it could allow for flexibility and customization in what people want."

A major challenge is manufacturing different materials alongside each other. “For example, printing plastic and steel side-by-side can be challenging because plastic melts at 200 degrees Celsius, whereas steel melts at 1,400 degrees Celsius,” Kiran says. “The right approach in this a case would be to develop two new materials which behave like steel and plastic respectively, but have physical properties close to each other.” 

Still, the sky may not be the limit for 3-D printing — Kiran envisions that the technology could build replacement parts and unplanned-for devices on space missions.

"We’re hoping that people will copy what we did and run with it," MacCurdy says.

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