The Bridge - Issue 1, 2021 - 14

Feature

Advanced Manufacturing Innovation Helps Industry in COVID-19 Fight

Advanced Manufacturing Innovation Helps Industry in COVID-19 Fight

" We had no capability to make this material but
wanted to be able to ramp up the production quickly, "
said Luis Arguello Jr., vice president of DemeTECH.
" Through a connection at the DOD's Advanced
Functional Fabrics of America, we were introduced to
ORNL and its success in making filter media material. "

ORNL's Merlin Theodore, who directs the CFTF, turned
to the precursor line's melt blowing capability for the
answer (Figure 4). The N95 mask is made of two
plies of melt-blown polypropylene, a non-woven
material that is permanently electrostatically charged
with millions of microfibers layered on top of each
other. The filter is capable of removing more than
95% of submicron particles found in viruses like
COVID-19.
Melt blowing is a nonwoven process that makes
microfibers into a fabric by scattering a polymer resin
at a high air velocity. Randomly deposited fibers form
a sheet of material applicable for filtration.
" We have the capability to melt blow polypropylene,
but we didn't have the capability to charge the fibers, "
Theodore said. " The charge is what's needed to
enhance the filter efficiency. "

Figure 3: ORNL is designing reusable face masks using the lab's
advanced manufacturing facilities. Credit: ORNL, U.S. Dept. of Energy.

(Figure 3). Rectangular holes can be drilled into the
outer mask to add straps.
" Uday's tooling is enabling us to use metal additive
manufacturing to rapidly produce injection molding
dies for reusable masks, " Love said. " With five sets of
tools, industry can potentially make 300,000 reusable
masks per week. "
DeRoyal, in turn, is working with another company
to do final assembly work on the mask, DeBusk said.
After assembly, DeRoyal will handle distribution of the
masks throughout the United States.
According to Love, the masks can be used hundreds
of times by replacing the filter layer made of N95
material. " We worked out the production process for
the N95 material too, " Love said. " And, we consulted
with the expert, Dr. Peter Tsai, the inventor. "

Filter material breakthrough
ORNL researchers were presented with the challenge
of how to produce filtration material for masks on
existing equipment typically used to mass produce
precursor material for carbon fiber production.

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That's where Tsai's knowledge was critical to the
CFTF's COVID-19 research. A retired University of
Tennessee researcher, Tsai invented electrostatic
charging, a process in which permanent charges are
embedded into a fiber to enhance filter efficiency by
electrostatic attraction. Tsai was consulted about how
a charging capability could be integrated into the melt
blowing line at the CFTF.
Tsai worked with the CFTF team to develop an
inline charging technology for the melt blowing line
and coordinated with staff at the MDF on material
blending. Materials were mixed using the reservoir
that normally holds polymers for 3D printing on the
Big Area Additive Manufacturing machine at MDF.
" We've been successful in melt blowing polypropylene
continuously on a belt, " Theodore said. " And, we've
translated it through an electrostatic charging system
to make the filter material. "
Researchers across multiple disciplines at ORNL in
materials science, characterization, and systems and
electrical engineering collaborated to adjust the speed
and feed of the material to achieve the optimum
production target of 65 grams of material per minute
with a fabric weight of 30 grams per meter squared.
" In just one week, we produced a material that meets
N95 requirements, " Theodore said.

Feature

Figure 4: Researchers at ORNL's CFTF used melt blowing to produce
electrostatically charged material for reusable masks and worked with
N95 inventor, Dr. Peter Tsai. Credit: Carlos Jones/ORNL, U.S. Dept.
of Energy.

" We're also working with Cummins (an engine and
power generation manufacturer), which has melt
blowing capability presently used for other filter
applications, in an effort to enable commercial
production of the N95 filter material. "
The Cummins technology used in air, fuel and lube
filtration is typically found in heavy-duty diesel engines
to prevent long-term engine wear but can also be
used in N95 respirator masks.
" Cummins is re-evaluating its supply base and
manufacturing capabilities to identify how to support
healthcare professionals who rely on critical personal
protective equipment to do their jobs, " said Amy
Davis, vice president of Cummins filtration.
The CFTF team has met speed requirements for
production scale-up so the material can ultimately be
supplied to companies like DeRoyal for distribution.
ORNL will work with industry on production, and
DeRoyal is testing the material for use in masks and
has placed an initial order.

N95 mask production
A collaboration between ORNL and a Florida-based
medical device manufacturer, DemeTech, has led to
the mass production of N95 respirator masks.
DemeTECH, a medical device manufacturer, is the
state's only National Institute for Occupational Safety
and Health certified producer of the respirator masks
needed to protect U.S. health care workers in the fight
against COVID-19.

Scientific research that began at ORNL provided melt
blown filter material to DemeTECH so that it could
develop its mask manufacturing processes. At the
beginning of the COVID-19 pandemic in the United
States, ORNL researchers were presented with the
challenge of how to produce filtration material on
existing equipment typically used to mass produce
precursor material for carbon fiber production.
Before COVID-19, DemeTECH primarily manufactured
wound closure medical devices such as surgical
sutures and hernia mesh. The company began
production of surgical and N95 masks in response
to health care supply demand. Since pivoting
the company's capabilities to producing masks,
DemeTECH has also opened two additional
production facilities.

Test tubes
ORNL was also tasked by the Department of Health
and Human Services to develop injection molding
tools for the mass production of plastic tubes for
COVID-19 test kits. The kits include a swab, saline
solution, and the plastic tube to enclose the swab
during transport.
" The U.S. goal is to ramp up production to enable one
test per person per month, which is 330 million test
kits per month, " Love said. " If we created a mold that's
designed to make 36 test tubes in a batch every 10
seconds, and the injection molding machine ran for
three shifts, manufacturers could make 300,000 tubes
per day. With multiple machines working around the
clock, you could achieve the 330 million goal. "
Love said test kit production is limited to one million
per week but is rapidly scaling up to 10 million per
week, which matches testing capacity.
" As testing capacity grows, so will the need to grow
the test kits, " he said. " We are in a race to rapidly
solve manufacturing problems currently facing the

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The Bridge - Issue 1, 2021

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