Evaluation Engineering - 34

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TECHNOLOGY INSIGHTS

3-D PRINTING
MATURES INTO
MANUFACTURING
By Ken Cormier, Managing Editor
3D printing, also known as additive
manufacturing, creates solid objects
from a digital file, with the ability to produce complex shapes, including hollow
forms. The technology has advanced far
from its beginnings in the '90s as a rapid
prototyping medium, to a viable cog in
industrial manufacturing. Here are a few
snippets about recent developments in
this rapidly changing technology:

GE Partners with U.S. Air Force
for Printing Spare Engine Parts
General Electric has successfully
3D-printed the sump cover for the F110
jet engine. Initially cast from aluminum,
the part, also used on F-15 and F-16 jet
fighters, was the focus for this first
phase of the collaboration. Engineers at
GE Aviation's Cincinnati-area Additive
Technology Center (ATC) created the
parts from cobalt-chrome powder, using
GE Additive's Concept Laser M2 machine.
"Part of that process involved how metal
additive might replace parts that are either no longer in production, or where
we need smaller production runs to keep
our platforms flying," explained Melanie
Jonason, chief engineer for the propulsion
sustainment division at Tinker Air Force
Base in Oklahoma.1

Human-Like Ears
3D-Printed Inside Mice
Scientist Maling Gou and colleagues at
Sichuan University, China, have grown
human-like ears on the backs of mice.
The technique could be used to create

EVALUATION ENGINEERING JULY 2020

body parts for people without resorting
to surgery. Up to now, spare human body
parts have been printed outside the body,
then surgically implanted, which carries
a risk for infection. In this experiment,
the researchers injected a "bio-ink" into
the backs of mice, which was subjected
to near-infrared light in the pattern of a
human ear, which caused the hydrogel
ink particles to solidify and develop, in
layers, into human ear structures. Within
a month, cartilage cells grew around the
structures. The researchers said that the
mice suffered no inflammation or side
effects. An intent of the study is to create ears for humans born without ears, a
condition called microtia. According to
Derek Rosenzweig at McGill University in
Canada, this printing technique has potential in repairing damaged cartilage in
noses, fingers, toes, or elbows. Rosenzweig
said that using the technique on hip and
deep knee cartilage would be a special
challenge, because near-infrared light penetrates only 2 centimeters into the body.2

Coronavirus Spurs Use
of 3D Printing
Emergency responders have been faced
with finding enough face shields for protection during the COVID-19 coronavirus
disaster. Fortunately, major defense contractors such as Raytheon Technologies
have been able to contribute what they
know in three-dimensional (3D) printing,
to form thousands of secure face shields
for first responders and other emergency
crew members.

"It was unprecedented to bring the
entire corporation together to print one
single file across multiple processes and
materials using somewhere around 100
machines in less than two weeks," said
Jesse Boyer, fellow for additive manufacturing at Raytheon Technologies. "To
ramp up to that volume that quickly is
something that is touted using additive
manufacturing, but rarely demonstrated.
The opportunity was a great learning
experience."
Instead of cutting or molding material,
3D printing, or additive manufacturing,
creates a part by building layer upon
layer to form the desired shape. This approach can provide extremely efficient
shapes and sizes that also work well
where space is at a premium, such as in
aircraft. "The wild side is to continue to do
that, to make very complex, yet optimized
structures for areas we couldn't normally
do in a jet engine," Boyer said. "We explore
methods like bio-mimicry, by looking at
the best nature has produced. Additive
then reduces the constraints of conventional manufacturing and substantially
increases our ability to optimize what we
can manufacture."3
REFERENCES

1. https://www.ge.com/reports/sump-it-up-geteams-up-with-us-air-force-to-3d-print-partsfor-fighter-planes/
2. https://www.newscientist.com/
article/2245295-human-like-ears-3d-printedinside-mice-as-surgery-free-spare-parts/
3. https://www.forbes.com/sites/
jamesconca/2020/05/09/3d-printing-hasentered-the-nuclear-realm/#b7352617d347

https://www.ge.com/reports/sump-it-up-ge-teams-up-with-us-air-force-to-3d-print-parts-for-fighter-planes/ https://www.newscientist.com/article/2245295-human-like-ears-3d-printed-inside-mice-as-surgery-free-space-parts/ https://www.forbes.com/sites/jamesconca/2020/05/09/3d-printing-has-entered-the-nuclear-realm/#49d7741e7d34

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