Medical Design Briefs - December 2021 - 31

How Top Trends in Cleaning are Impacting Medical Device Design
Ongoing advances in medical device design are
meeting patients' demands for more portable
and wearable technology. Bulky external health
devices, like ECG monitors, spinal stimulators,
and insulin pumps, are now slim and discrete. The
patient benefits of these advances can be lifechanging
with improved physical comfort and
mental well-being. However, for manufacturers, it
is a challenge to design and build these new
miniaturized complex devices.
■ Cleaning - A Critical Production Step for
Wearables
Effective design practices are critical to deliver a
device that performs as intended. When designing
wearables, there are many factors an engineer
must consider and plan for before any prototyping
or production starts. However, cleaning is a
critical aspect of medical device design that is
often overlooked during initial planning.
Medical devices must be cleaned and dried to
the highest standards to ensure their readiness for
the next step in the manufacturing process.
Production debris like machining, stamping, or cooling oils,
dust, metal filings, marking inks, fingerprints, and other soils
must be removed prior to assembly, packaging, sterilization, or
coating. Any remaining particulate or residue can lead to
inconsistent outcomes and impact the devices' performance.
Smaller medical devices often have tiny spaces that are more
difficult to clean and dry during manufacturing. They often
include tight crevices, blind holes, or intricately shaped openings
that are particularly difficult to clean. In addition, modern
devices are made with more delicate parts and varied materials.
Softer plastics and lightweight metals can be easily damaged, so
cleaning and drying must be done carefully to prevent harm.
As a result, medical device manufacturers require newer, better
cleaning fluids and methods to get the devices clean and
dry. The cleaning fluids must penetrate all areas of the complex
geometries, awkward shapes, and blind holes. Plus, they
cannot leave residue or damage sensitive materials such as
polycarbonate and acrylic.
■ The Resurgence of a Tried and Tested Method
Vapor degreasing meets that demand and continues to grow
in popularity for medical device cleaning and drying. A few
decades ago, vapor degreasing was the preferred method for
cleaning medical devices. It was easy to use and provided highly
reliable cleaning performance. However, in the late 1990s,
environmental concerns fueled an industry-wide trend to
switch from this process to aqueous-based cleaning systems.
Although there were disadvantages to using the water cleaning
systems, like high energy and water consumption, many
device manufacturers were convinced it was environmentally
better than vapor degreasing, which uses solvent-based cleaning
fluids. However, recent advancements in solvent technology
have generated more environmentally friendly fluids, which
have led to renewed interest in vapor degreaser cleaning.
Medical Design Briefs, December 2021
Cov
Production debris must be removed prior to assembly, packaging, sterilization, or coating.
(Credit: MicroCare)
■ Future Trends in Cleaning Fluid Technology
Nearly all of the recent advances in cleaning fluid technology
are focused on developing safe chemistries that meet both
cleanliness standards and environmental regulations - meaning
they do not contribute to global warming and are not an
ozone depleting substance. In the past, high-performing cleaning
solvents used within a vapor degreaser such as trichloroethylene
(TCE), perchloroethylene (perc), and n-propyl bromide
(nPB) presented air and groundwater quality issues as well as
health and safety concerns.
That resulted in layers of regulations established to discourage
their use. Early efforts to develop cleaning solvent alternatives initially
resulted in ineffective cleaning that did not meet exacting
standards - especially those needed in the medical device space.
■ The Green Clean
Because of their improved environmental and safety profiles,
modern vapor degreasing fluids make ideal long-term replacements
for the less planet-friendly solvents. Importantly, they not
only meet today's environmental regulatory demands, but are
also equipped to meet emerging " green " rules for the future.
Today, there are a number of modern cleaning fluids available
that are both very effective and environmentally progressive.
They offer excellent cleaning performance combined with a
low GWP (global warming potential) and low ODP (ozone
depleting potential) profile. How the fluid ingredients are
combined determines the cleaning fluid's effectiveness and its
material compatibility. The vapor degreaser can use just one
type of cleaning fluid or fluids can be mixed, blended, or custom
formulated to remove a specific soil from a specific device,
maximizing cleaning effectiveness.
These next-generation fluids maintain or even increase cleaning
consistency. This reduces scrap and rework, which lessens the
number of raw materials used to complete an order. They also
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Medical Design Briefs - December 2021

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