CMU researchers develop technique for printing hair strands
November 3, 2015 12:00 AM
An example of the 3-D printed hair by Gierad Laput, a Ph.D. student at CMU's Human-Computer Interaction Institute.
By Sophie Wodzak / Pittsburgh Post-Gazette
A team of researchers at Carnegie Mellon University’s Human-Computer Interaction Institute has figured out how to create soft, silky hair through a new 3-D printing technique it calls “furbrication.”
Until now, 3-D printers have been able to produce only solid objects. According to Gierad Laput, a Ph.D. student at the institute, this new technique extends the breadth of projects that 3-D printing can execute to include softer, more flexible textures.
“3-D printing is a very promising technology, but at the moment it’s not something most people have a need for,” said Chris Harrison, assistant professor at the institute. “If they are to become truly general-purpose machines, capable of creating a whole vocabulary of objects, we need to work on extending their capabilities, so that they can print any object imaginable.”
To that end, Mr. Laput’s work involves expanding the possibilities of 3-D printing by finding unconventional ways to use the technology. He says inspiration for furbrication came from an unlikely source: the sticky threads that are often the byproduct of working with hot glue. Because the Fused Deposition Modeling 3-D printer the team used works much like a hot glue gun, extruding threads of molten plastic through a heated nozzle, Mr. Laput and his team thought they might be able to produce hair-like strands using a similar technique.
The problem was that because 3-D printers operate by layering these threads of plastic in a series of horizontal layers to create a 3-D object, their nozzles aren’t designed to pull backward quickly enough to produce the thin, tapered strands needed to achieve a hair-like effect. So the researchers decided to try another angle.
“Moving the printer’s head vertically is a very slow process, but it can move horizontally very quickly. So we thought we’d give that a try,” Mr. Laput said. As it turns out, what matters is not the direction you pull the plastic but the distance and speed with which you pull it. By depositing small globs of molten plastic on a base mounted on a printing bed, and then quickly moving the nozzle and the printing bed away from each other horizontally, Mr. Laput’s team was able to produce the hair-like strands they were trying to create.
Depending on how and where the blobs of plastic are applied, various hair styles are possible. Randomized root positions of varying thickness can produce anything from a long silky wizard’s beard to the short, sparse patches of hair on a human finger. A denser, more uniform application can create the stiff bristles of a toothbrush.
Technology for creating synthetic hair-like fibers has existed for years and is used to make doll hair, wigs and toothbrushes. But as Mr. Laput points out, these manufacturing processes require expensive specialty machining techniques. Furbrication, on the other hand, requires no special hardware, aside from the printer itself.
“We wanted to generate something accessible,” Mr. Laput said. “Our printer is the cheapest one out there, and the plastic we’ve chosen to use, polylactide, is the most common and basic 3-D printing material.”
The FDM printer the team used costs an average of $300, although in this case the team members built the printer themselves, with parts they bought online. The resulting strands of polylactide can be cut, braided, and even curled with hot air.
Mr. Laput says that using a more sophisticated material, such as acrylonitrile butadiene styrene, could be used to produce hair with magnetic or other properties.
The method does have drawbacks. Producing the hair is a slow process; to cover an area of 10 square millimeters takes nearly half an hour. Because the extruder that the team used is fairly wide, it is unable to produce very dense fine hair. Mr. Laput says now that they’ve figured out how to make strands this way, the next step will be figuring out how to make the hairs more dense and robust.
The team debuted its technique at an Engadget Live event in Liberty Warehouse in Brooklyn, N.Y. last week. It will give another demonstration Nov. 11, at UIST 2015, the ACM User Interface Software and Technology Symposium, in Charlotte, N.C. The research was supported by the David and Lucile Packard Foundation, Google, Yahoo! and Qualcomm.
Sophie Wodzak: email@example.com or 412-263-1525.
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