Medical Manufacturing and Outsourcing Special Report - November 2021 - 11

Many times, early adopters had
to make economically unfavorable
compromises to ensure product
quality while also delivering
products to the market in a timely
manner. For example, they may
not have had time to perform
a comprehensive study on the
effects of powder reuse on the
properties of finished products.
The manufacturer's specifications
would then limit the amount of
times powder could be reused
based solely on the amount
of reuse their pre-launch R&D
activities afforded them in lieu
of any technical considerations.
During the period of early
adoption, the FDA treated additive
manufacturing like any other emerging
technology. They had materials
experts and process control experts
for traditional manufacturing, but
AM experts did not exist. So, as
manufacturers were establishing
their own specifications for additive
manufacturing, the FDA relied on
manufacturers to provide guidance
on how to control and monitor AM
processes. Soon, however, it became
clear that additive manufacturing was
going to be larger than the average
technological advance. When the FDA
realized additive manufacturing was
creating a cultural shift in manufacturing,
they saw a need for the development of
new guidance documents specifically
for this new manufacturing method.
Establishment of ASTM F42
(2009) and the Deployment of
FDA AM Guidance
In 2009, ASTM created a committee
for additive manufacturing technologies
(ASTM F42), which led to the creation of
some of the first AM-specific standards.
The first standards defined terminology
for the AM industry and established
several AM material standards. The
ASTM F42 committee was created to
address the needs of the entire AM
community, including industries like
aerospace, automotive, and medical.
As a result, the AM materials and
test method specifications created
sintering [SLS]) and metals (laser
powder-bed fusion [LPBF]). Under
this guidance, manufacturers
must address considerations such
as orientation, build location,
powder reuse, and mechanical
properties and provide data
and justification as to why and
how they did or did not include
these variables in their design
and process validation efforts.
This document allows medical
Intricate porous structures are easily achieved via AM. However,
their use requires extensive characterization and testing. Special
test specimens, like this porous shear strength specimen, are
often utilized during the development stages of an AM implant
product. (Credit: Cretex Medical)
were very broad to accommodate
all members of the community.
These specifications had a degree
of helpfulness to all industries using
additive manufacturing but were not
sufficient for any specific industry as it
was not possible to include all necessary
details for each individual industry.
Since the formation of ASTM F42,
the committee has been in the process
of developing guidance documents
specifically for the medical device
industry. A subdivision of ASTM
F42 has been created for medical
applications (ASTM F42.07.03), which
is working on creating medicaldevice-specific
terminology, process
control protocols, and best practices
for processes like powder handling
and powder recycling. However, the
subcommittee has a long way to
go to develop all the specifications
necessary to standardize additive
manufacturing for the medical industry.
In 2017, the FDA worked with industry
experts to release a document titled
Technical Considerations for Additive
Manufactured Medical Devices. Like
ASTM's document, it is broad in scope
to accommodate a variety of device
types and use factors like patientmatched
implants, off-the-shelf devices,
instruments, and anatomical models.
The document is also comprehensive
to cover a variety of processes and
materials including both polymers
(stereolithography [SLA], selective laser
MEDICAL MANUFACTURING AND OUTSOURCING SPECIAL REPORT
device manufacturers to
understand what the FDA expects
when submitting a product for
clearance. Unfortunately, this
document has the same issue
as the early ASTM standards.
While it lists many factors that need
to be considered when testing and
establishing a process or product
utilizing additive manufacturing,
because it is so broad, it cannot
delve into the necessary details
for each material and process.
Additive Manufacturing Today
Many of the early adopters of
additive manufacturing that received
FDA clearance on their devices 10
or 15 years ago are now at the point
where they are replacing some of
their legacy AM products with newly
designed products. They are realizing
that the path they utilized to gain FDA
clearance 10 years ago is not what the
FDA expects today. The FDA now has a
better understanding of the AM process
and has altered their expectations
accordingly. Rather than relying on
medical device OEMs to provide
information, the FDA has formed
their own requirements and guidance.
Medical device manufacturers cannot
gain FDA approval of their AM devices
by relying on outdated regulatory
strategies from the early days of additive
manufacturing. Today, manufacturers
must comply with increasingly
stringent specifications and validation
requirements. AM devices also see
more scrutiny from the FDA compared
to traditionally machined devices. The
administration looks more closely at
mechanical performance for AM products
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Medical Manufacturing and Outsourcing Special Report - November 2021

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