Medical Manufacturing and Outsourcing Special Report - November 2021 - 28

TECH BRIEFS
diamond abrasive for use on materials
like carbide, ceramic, and steel alloys
as well as a CBN (cubic boron nitride)
option that is even harder and is
specifically designed for superalloys,
which can exhibit of high ductility
and work hardening that produce a
gummy machining behavior if the
correct abrasive tool is not utilized.
He notes that when deburring
superalloys such as titanium or 13-8
stainless alloy, utilizing the Flex-Hone
has been very helpful. " Most of the
13-8 we machine is heat-treated, so
it is subject to significant burrs. The
hone is ideal for removing even the
most stubborn burrs, " says Garaczi.
Garaczi is installing the flexible hones
into CNC equipment to automate the
process and reduce the time required to
finish superalloys and stainless steels.
Despite the fact that these are
abrasive tools, Garaczi says that even
though " abrasives " are often all lumped
into the same category, a distinction
must be made between abrasives
used for aggressive material removal
and abrasive finishing tools. Finishing
tools release little to no abrasive grit
during use, and the amount generated
is comparable to the metal chips,
grinding dust and tool abrasion created
during the machining process itself.
Even if minimal fine solids are
produced, the filtration requirements
for abrasive tools are not much different
than for machining. Any particulate can
be easily removed using inexpensive
bag or cartridge filtration systems.
He says that when making decisions
about what tools to purchase it is often
on a project-by-project basis. However,
if the tool can reduce cycle times
versus its cost, it is an easy decision.
The use of the hone is even helping
Delta cope with the demands placed
on it by COVID-19, by accommodating
more work being done in an automated
manner. This not only requires less labor,
but also facilitates social distancing
for any workers on the production
floor. " I want to do everything on
the CNC machines whenever I
can, especially now, " he says.
To achieve this, the machine shop
incorporates Flex-Hones in a variety
of sizes in its tool carousels.
" For a part, we might use two to
three different size hones, depending on
the number of cross port intersections
and different hole sizes, " says Garaczi.
" However, it is really easy to put a
Flex-Hone into a toolholder, give it a
simple tool path cycle and let it run. "
Garaczi says that automating
cross-hole deburring eliminates
a lot of off-line work, since Delta
Machine's parts are usually complex
with many intersecting holes.
" It is difficult for a person to reliably
repeat such work to the level of required
quality. Automating this with the CNC
machine usually will produce more
consistent results, while enabling greater
social distancing among our staff on
the production floor, " says Garaczi.
For more information, visit
http://info.hotims.com/79416-342.
3D Printing Technique Creates Intricate Medical Implants
The biomedical structures advance the development of new technologies for regrowing
bones and tissue.
RMIT University, Melbourne, Australia
he emerging field of tissue
engineering aims to harness the
human body's natural ability to heal
itself, to rebuild bone and muscle lost
to tumors or injuries. A key focus for
biomedical engineers has been the
design and development of 3D printed
scaffolds that can be implanted in the
body to support cell regrowth. But
making these structures small and
complex enough for cells to thrive
remains a significant challenge.
Enter an RMIT University-led
research team, collaborating with
clinicians at St. Vincent's Hospital
Melbourne, who have overturned
the conventional 3D printing
approach. Instead of making the
bioscaffolds directly, the team
28 NOVEMBER 2021
T
3D printed molds with intricately
patterned cavities then filled them
with biocompatible materials,
before dissolving the molds away.
Using the indirect approach,
the team created fingernail-sized
bioscaffolds full of elaborate
structures that, until now, were
considered impossible with
standard 3D printers. Lead
researcher Dr. Cathal O'Connell
says the new biofabrication
method was cost-effective and
easily scalable because it relied
on widely available technology.
" The shapes you can make with a
standard 3D printer are constrained by
the size of the printing nozzle - the
opening needs to be big enough to
let material through and ultimately
that influences how small you can
print, " O'Connell, a Vice-Chancellor's
Post doc toral Fellow at RMIT, says.
" But the gaps in between the
printed material can be way
smaller, and far more intricate.
" By flipping our thinking, we
essentially draw the structure we
want in the empty space inside our 3D
printed mold. This allows us to create
the tiny, complex microstructures
where cells will flourish. "
O'Connell says other approaches
were able to create impressive
structures, but only with precisely
tailored materials, tuned with
particular additives or modified
with special chemistry.
MEDICAL MANUFACTURING AND OUTSOURCING SPECIAL REPORT
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Medical Manufacturing and Outsourcing Special Report - November 2021

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