Page 40 - Plastics News December 2022

FEATURE

Adding a Fourth Dimension to 3d Printing
throughout the filament. With the
sensors dispersed evenly in the fila-
ment, manufacturers and researchers
can design parts with a wider variety
of shapes.
“The results from this work enable us-
ers to create complex 3D structures
with embedded strain gauges, rapidly
moving traditional prototype pieces
into fully functional and structurally
assessable parts,” Newell said. “A
limitation of application of 3D printed
parts has been in their durability. With
this development, we can continually
monitor the structural health of the
urdue University researchers are adhered to the surface of a print- part with the sensor embedded in the
Phave developed a patent-pending ed part by an epoxy resin, Newell print.”
method to add particles to filament said. However, in this work the sprin-
and disperse them evenly through a kles are added throughout the cookie Tallman said, “This method produces
traditional fused deposition modeling, dough before baking. This means that materials that are conductive with
or FDM, 3D printer, which will aid sensing capabilities are an inherent very good uniformity, which greatly
industry in manufacturing functional part of the printed component and expands the electrical applications of
parts. allow for sensing inside of the com- 3D printed parts and sensor designs.”
Brittany Newell and Jose M. Garcia- ponent. Unlike sprinkles, these sen- Garcia-Bravo said, “The materials are
Bravo, associate professors in the sors are too small to be seen without also tunable, meaning we can adjust
School of Engineering Technology in a microscope. Their tiny scale allows the electrical and mechanical proper-
the Purdue Polytechnic Institute, and the printed part to maintain strength ties to optimize the sensor or part for
Tyler Tallman, assistant professor in it would have otherwise sacrificed a desired application.”
the School of Aeronautics and Astro- due to large sensors built in, while The novel wet-mixing process is not
nautics in the College of Engineer- still achieving fully integrated sensing limited only to sensor conductivity.
ing, have created a novel wet-mixing capabilities. “This work can be further expanded
method to introduce electrically con- “Generally, we apply that strain to add other particle types using the
ductive particles into 3D printing fila- gauge across the full part or apply it same wet-mixing method,” Newell
ment polymers. Cole Maynard, who to the top and bottom of the part to said.
earned his PhD in August, and Julio get information on
Hernandez, a doctoral candidate, overall strain across
were pivotal to the research. the part,” Newell

Traditional 3D printing makes proto- said. “However, the
types of parts with no sensing capa- middle and internal
bilities. Sensors must be added to the structures are never
part after the fact if assessments are to monitored since the
be made. The process can be thought gauges are glued to
of as adding sprinkles to cookies after the surface.”
they are baked: The sprinkles exist The Purdue wet-
only on the outside of the cookie. Tra- mixing method en-
ditional foil-type strain gauges, which sures an even distri-
are the most common strain sensors, bution of particles

40 PLASTICS NEWS December 2022