Tech Briefs Magazine - May 2022 - 34

Manufacturing &
Prototyping
New Printing Process Advances 3D Capabilities
The technology could improve the quality of products such as prosthetics and medical devices,
and parts for airplanes and automobiles.
University of Massachusetts, Lowell, MA
S
ubstances such as plastics, metals,
and wax are used in 3D printers
to make products and parts for larger
items. Products created through the
3D printing of plastics include everything
from toys to drones. Challenges
remain in ensuring the printers create
objects that are produced quickly, retain
their strength, and accurately reflect the
shape desired.
This object was created by the injection printing
process. (Photo: UMass Lowell)
A technology called injection printing
combines elements of 3D printing and
injection molding, a technique through
which objects are created by filling mold
cavities with molten materials. The combination
of the two processes increases
the production rate of 3D printing, while
enhancing the strength and properties of
the resulting products. The innovation
typically produces objects about three
times faster than conventional 3D printing,
which means jobs that once took
about nine hours now only take three.
The process greatly improves the quality
of the parts produced, making them
fully dense with few cracks or voids, so
they are much stronger. The new process
can be used in existing 3D printers, with
only new software needed to program
the machine.
For more information, contact Nancy
Cicco at Nancy_Cicco@uml.edu; 978-9344944.
3D
Printing Process Uses Light to Improve Precision
and Speed
In combination with a robot arm, the process provides the freedom to move, rotate, or dilate
each layer as the structure is being built.
Northwestern University, Evanston, IL
M
ost conventional 3D printing processes
rely on replicating a digital
design model that is sliced into layers
with the layers printed and assembled
upward like a cake. A new method introduces
the ability to manipulate the
original design layer-by-layer and pivot
the printing direction without recreating
the model. This " on-the-fly " feature
enables the printing of more complicated
structures and significantly improves
manufacturing flexibility.
The dynamic process uses light to
assemble the layers but with a high
degree of freedom to move each layer
along the way. The researchers demonstrated
several applications including
3D printing a customized vascular stent
z

Y
X
Printing
path
and printing a soft pneumatic gripper
made of two different materials: one
hard and one soft.
The process uses a robotic arm and
a liquid photopolymer that is activated
by light. Sophisticated 3D structures
are pulled out from a bath of liquid
resin by a high-precision robot with
enhanced geometric complexity, efficiency,
and quality compared to the
traditional printing process. The arm
is used to change the printing direction
dynamically.
Shining light on the liquid polymer
causes it to crosslink, or polymerize, converting
the liquid to a solid. This contributes
to the speed and precision of
the 3D printing process. The continuous
printing process can print 4,000 layers in
approximately two minutes. The general
printing method is compatible with a
wide range of materials.
2 mm
2D Shear + 1D Twist
This tiny Eiffel Tower was produced using the dynamic 3D printing method that has the ability to change
printing direction on the fly. The printing path is shown on the right. (Photo: Northwestern University)
34
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The researchers believe the printing
process could be applied to other additive
as well as traditional subtractive
manufacturing processes, providing a
bridge toward a truly hybrid process.
For more information, contact Megan
Fellman at fellman@northwestern.edu; 847 -
491-3115.
Tech Briefs, May 2022
TB Manufacturing Prototyping 0522_1.indd 34
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