Medical Design Briefs - February 2023 - 14

DfM and Product Development
are also important to consider because
these influence cavitation requirements
and directly affect complexity.
Critical to quality (CTQ) features
and tolerances are just as important
to project success as a robust mold
design because they represent the
product characteristics as defined by
a customer (internal or external).
CTQs drive mold design decisions
by influencing manufacturing methods
and a tool layout that would best
achieve these critical requirements.
Design and Collaboration
DfM is vital as it truly establishes a
partnership between medical device
manufacturer and supplier during the
product development process. When
making precision plastics parts and
components, micro molding per se is
only one part of the product development,
albeit a very important one. It
is important for medical device OEMs
to appreciate that various departments
involved in a micro manufacturing
project need to be engaged from product
design inception.
Absolutely critical for success is to
reassess the nature of the relationship
between medical device OEM and
molder in a micro molding scenario.
When dealing with contract manufacturers
on the macro level, the relationship
can quite acceptably be that of a
job shop. The design is presented, the
quote is secured, and the parts are delivered.
Job done.
This cannot and will not work when
undertaking a micro molding project,
which necessitates that the medical device
OEM and the chosen micro molding
company enter a fully collaborative
partnership relationship. The reasons
for this are numerous but begin with
the fact that just as micro molding and
the macro molding are completely different
processes, the DfM rules are also
entirely different.
DfM for micro molding is hugely important,
and the expert in the room to
offer advice and counseling is the expert
micro molder. Very often, the less
baked an idea is when the micro molder
is engaged the better, as the earlier
that the design of a micro product
can be influenced and adjusted to optimize
manufacturing outcomes, the
better in terms of cost and timeliness
of production.
14
Examples of micro molded optics. (Credit: Accumold)
Essentially, DfM ensures that not
only will the end product be fit-forpurpose
but that it is also optimized
for the production processes that will
be used to manufacture it - in this
case micro molding and automated
assembly. The micro molding team
should be able to advise on such issues
as material choice, draft angles and
undercuts, part lines, ejector pin locations,
gate locations, the likely flow of
material in the mold, wall thicknesses,
etc. Perhaps the key enabling technology
when it comes to micro molding
is micro tooling. Tooling in any manufacturing
scenario is always the costliest
and most time-consuming part of
the product development process, but
when looking at micro molding, the
tolerances and complexity that is often
required in micro molds make it especially
critical.
A variety of micro injection molded parts, including examples of micro gears, overmolded switch
components, housings, and connector parts. Materials include LCP, Nylon, PEI, and PEEK. (Credit:
Accumold)
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Medical Design Briefs, February 2023

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Medical Design Briefs - February 2023

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