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Multimaterial Multinozzle 3D
(MM3D Printing), a new technique
developed by engineers at the
Wyss Institute and Harvard SEAS,
allows seamless switching
between up to eight different
materials within a single
nozzle.
MM3D printing can create complex
3D objexts in a fraction of the
time required by other extrusion-
based 3D printing methods.
Each nozzle can switch materials
50 times per second, which is
faster than the human eye can
detect.
The rapid ink switching is
achieved with high-speed
pneumatic actuators that apply
pressure to
multiple ink channels that
converge in a series of Y-shaped
junctions inside the printhead.
Precise tuning of the nozzle
shape, printing pressure, and
ink viscosity prevents
the flowing ink from mixing or
back-flowing into the static ink
channel when pressure is
applied.
This one-way flow behavior works
like railroad signaling,
ensuring only one material at a
time
moves through the print nozzle.
This preserves the quality and
detail of the printed object.
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The researchers used MM3D printing
to create an actuating soft
robot with 16 "feet" composed of
rigid and soft elastomers with
embedded pneumatic channels.
Alternating the position of
the rigid elastomers between
the outer and inner rows of
"feet" and
sequentially compressing the
channels with a vacuum allows
the soft robot to "walk".
It was able to move at nearly
half an inch per second and
carry a load eight times its
own weight.
Currently, the research team is
modifyng MM3D printing to enable
individually addressable nozzles
that each extrude different inks
on demand to produce even more
complex objects.
