These days, it may seem as if 3-D printers
can spit out just about anything, from a full-sized
sports car, to edible food, to human skin.
But some things have defied the technology,
including hair, fur, and other dense arrays
of extremely fine features, which require
a huge amount of computational time and power
to first design, then print.
Now researchers in MIT’s Media Lab have
found a way to bypass a major design step
in 3-D printing, to quickly and efficiently
model and print thousands of hair-like structures.
Instead of using conventional computer-aided
design (CAD) software to draw thousands of
individual hairs on a computer — a step
that would take hours to compute — the team
built a new software platform, called “Cilllia,”
that lets users define the angle, thickness,
density, and height of thousands of hairs,
in just a few minutes.
Using the new software, the researchers designed
arrays of hair-like structures with a resolution
of 50 microns — about the width of a human
hair.
Playing with various dimensions, they designed
and then printed arrays ranging from coarse
bristles to fine fur, onto flat and also curved
surfaces, using a conventional 3-D printer
Could the technology be used to print wigs
and hair extensions?
Possibly, say the researchers.
But that’s not their end goal.
Instead, they’re seeing how 3-D-printed
hair could perform useful tasks such as sensing,
adhesion, and actuation.
To demonstrate adhesion, the team printed
arrays that act as Velcro-like bristle pads.
Depending on the angle of the bristles, the
pads can stick to each other with varying
forces.
For sensing, the researchers printed a small
furry rabbit figure, equipped with LED lights
that light up when a person strokes the rabbit
in certain directions.
And to see whether 3-D-printed hair can help
actuate, or move objects, the team fabricated
a weight-sorting table made from panels of
printed hair with specified angles and heights.
As a small vibration source shook the panels,
the hairs were able to move coins across the
table, sorting them based on the coins’
weight and the vibration frequency.
