Medical Design Briefs: 2021 Technology Leaders - 34

TECHNOLOGY LEADERS Tubing/Extrusion
Tubing Capabilities to Improve Efficiency
and Quality in Medical Device Manufacturing
T
he COVID-19 pandemic has
brought into clear focus the need
for safe, sterile surgical devices.
Accordingly, healthcare providers
are increasingly turning to single-use or
disposable products. Disposable surgical
products inherently reduce risk of infection
related to cleaning and sterilization
since they are presterilized and individually
packaged. Such devices are often
viewed as safer alternatives to reusable
devices, as the latter can still lead to
infection in some cases. Many in the
medical device industry will recall news
stories relating to field recalls of some
reusable surgical devices that had complex
designs and intricate parts that were
challenging to clean thoroughly. As the
healthcare industry increasingly moves
toward an outcomes-based model, solutions
such as disposable products that
can drive better outcomes for patients
help meet the needs of hospitals to provide
value-based healthcare. In light of
all of this, it is perhaps not surprising that
the use of disposable surgical instruments
continues to gain favor.
Stainless steel tubing is a primary support
feature of single-use handheld surgical
devices. Medical device OEMs and
contract manufacturers have a number
of options to choose from for producing
these tubes efficiently and cost-effectively,
ranging from manual production to
fully automated systems. Depending on
the device being produced - along with
factors such as volume and features
needed - drawn, or stamped and
rolled, tubing can be used to manufacture
metal tubes quite effectively.
Several criteria must be factored in
during the design stage before determining
which technique to use, including
the size of the components, tolerance,
thickness of the tubes, and whether the
device will require the tube to move or
remain static. Design engineers should
be aware that these factors play a critical
role in the type of process that can be
used to produce a given tube. For
instance, wall thickness may well dictate
34
Rolled Tube Technology can reduce both component and subassembly costs of single-use handheld endoscopic
surgical devices such as scissors, graspers, dissectors, and tissue-holding forceps. (Credit: MICRO)
which process is selected. Generally
speaking, most single-use medical tubing
tends to be thin-walled, typically 0.010-in.
thick, and can be produced in a variety of
manners. By contrast, a thicker wall of
0.030 or 0.040 in. usually requires a ma -
chining process to accommodate tube
features such as grooves and slots.
Drawn Tubing Approach
Stainless steel tubing can be drawn in
a range of profiles. Stock tube is extruded
through a die to achieve a particular
cross section. Drawn tubing is typically
used when tightly controlled dimensions
such as straightness or strict diameter
consistency are needed for critical functions
throughout the entire length of the
metal tube shaft. Drawn tubing is also a
good choice for more robust end features
such as flanging and flaring, expansions
or reduction features, or end sharpening.
In addition, drawn tubing is usually
better suited when additional processes
are needed; for example, for piercing
and slotting, precision sharpening, electropolishing,
and laser welding and for
projects that require secondary assembly.
'Rolled' Tubing Method
One cost-effective way to produce
high-volume thin-walled stainless steel
tubing is through a progressive stamping
process which actually " rolls " the tube
into its final form. This innovative
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method allows a tube to be stamped out
of flat stock, resulting in a finished tube
with complex features. Features such as
holes, slots, and windows can be
punched into raw flat stock during the
initial stage of the stamping process.
This process helps reduce production
time and component expenses, along
with costly and time-consuming secondary
operations. It is now possible to stamp
and roll a finished tube using a power
press in just a few seconds, as opposed to
drawing raw tubing, cleaning it, cutting it
to the desired length, and processing secondary
features. This method is best
reserved for higher volume parts - generally
quantities greater than 300,000
pieces. MICRO'S patented, Rolled Tube
Technology, for example, can reduce
both component and subassembly costs
of single-use handheld endoscopic surgical
devices such as scissors, graspers, dissectors,
and tissue-holding forceps.
Automation
Fully integrated systems allow fulllength
drawn metal tubing to be used
with automated work cells, a process that
can combine operations, shortening
setup and cycle times that can reduce
costs. Rather than precutting tubing,
integrated systems allow the 10-ft tubing
to be fed into a machine in one automated
process, increasing productivity and
decreasing cost and waste. In addition,
Medical Design Briefs 2021 Technology Leaders

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Medical Design Briefs: 2021 Technology Leaders

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