A loudspeaker playing a clip of President Barack Obama talking about 3-D printing in his State of the Union speech might not seem so remarkable—except that the loudspeaker represents one of the first 3-D printed consumer electronic devices in the world.
The 3-D printed loudspeaker is more expensive, took longer to make, and is of a lower quality than a typical mass-produced speaker, said Hod Lipson, an associate professor of mechanical and aerospace engineering at Cornell University. But he described his lab's demonstration to IEEE Spectrum as providing a "glimpse of the future" by showing that 3-D printing technology can eventually create all the necessary components of electronic devices:
"The real challenge is one of material science: Can we make a series of inks that can serve as conductors, semiconductors, sensors, actuators, and power. These inks have to have good performance and be mutually compatible. We're not there yet, but I think its well within reach—we'll see a variety of platforms well within the next 5 years."
Most 3-D printers usually build objects layer-by-layer from a single "passive" material such as plastic. But researchers have been testing how to use 3-D printing to squirt out conductive inks that can form the building blocks of integrated systems such as electronic devices.
The Cornell project—headed by mechanical engineering graduate students Apoorva Kiran and Robert MacCurdy—used two of the lab's homegrown Fab@Home printers to create the 3-D printed loudspeaker parts. One printer made the plastic cone and base of the loudspeaker. The second printer laid down the wires on the cone and created a magnet inside the plastic base. (The team swapped out the second printer's ink cartridge from conductor to magnet ink between printing runs.)
Silver ink provided the conductive material for the wire. For the magnet, Kiran enlisted the help of Samanvaya Srivastava, a graduate student in chemical and biomolecular engineering, to develop a strontium ferrite blend. Two Cornell undergraduates, Jeremy Blum and Elise Yang, also worked on the project.
The 3-D printed loudspeaker didn't come out all in one piece—researchers manually moved the parts between the two printers and then snapped the cone and base together to complete the device. But Lipson says the complete loudspeaker could be printed on a single 3-D printer if the printer had multiple deposition tools capable of squirting out the different materials needed for the plastic, wires and magnet. Such printers could already be developed within labs in a month or so from a technical standpoint, but the business demand is not there yet with 3-D printed electronics still in their infancy.
Lipson previously worked with former Cornell graduate students, Evan Malone and Matthew Alonso, to create a 3-D printed version of a working telegraph modeled on the Vail Register—the famous machine that Samuel Morse and Alfred Vail used to send the first Morse code telegraph in 1844. By comparison, the 3-D printed loudspeaker represents a relatively modern example of a commercial electronic device.
Once 3-D printing gets the hang of making electromagnetic systems, the technology could open the door for new customizable shapes and optimized performance for specific electronic devices—features that mass manufacturing can't offer. Lipson described the idea of creating 3-D printed headsets, microphones, and other devices custom-made.
Eventually, 3-D printing could also revolutionize the manufacturing of robots. Lipson's lab envisions using 3-D printers to build robots with "embedded wires and batteries shaped like limbs," as well as all the other necessary components of robotic technology.
"We hope to be able to develop working electromagnetic motors in the future which would be the cornerstone upon which printed robots could be built," said Robert MacCurdy, one of the Cornell graduate students heading the 3-D printed speaker project.
Photo: Cornell University