The first 3D printer that can churn out soft objects made its debut last month at the Computer Human Interaction conference in Toronto, Canada. It has already made small woollen teddy bears, and could one day be used to create electronics that are easy on the skin. That could pave the way for a new generation of body-monitoring sensors and lifelogging devices that can be discreetly embedded in clothing.
“The things that we hold close to our body, we would like them to be soft,” says Scott Hudson at Carnegie Mellon University in Pittsburgh, Pennsylvania, who led the team that devised the printer. He says he wants interactive devices, which are typically made of rigid materials, to be able to take on forms that we like having close to ourselves.
Initially, the machine could only work with melted plastic. Hudson replaced the print head with one he custom-built, which controls a needle threaded with yarn. Printing is then a matter of specifying the object using 3D design software and running a separate program to break the design down into instructions for the device. It executes these by laying down successive layers of stitches, all the while keeping the yarn loose enough to avoid unpicking previous stitches (pictured below).
The object is specified using 3D design software, and the printer then lays down layers of stitches
To go beyond making teddy bears, the printer must be able to combine yarn with other types of material. For the time being, the researchers have been able to manually place devices inside the bears as they are being printed. They have also created bendable joints at the elbow, wrist and shoulder by printing the bear’s arms around tubes of nylon mesh.
The team is also experimenting with ways to embed electronics inside the bears without puncturing the circuitry or breaking the print needles. In one “torture test” they tried printing directly over rigid wires to see how much resistance the machine could cope with. Other objects the team printed had small internal pockets that could be used to hold devices.
The soft printer is an great example of how far such machines have come, says Stephen Ervin of the Harvard University Fabrication Laboratory. It could extend 3D printing’s appeal to “a large and diverse audience of users and uses”, he says.
This article appeared in print under the headline “3D printing masters the art of soft toys”
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