Medical Design Briefs - October 2023 - 13

soldering stations, and improving
process throughput
quality and repeatability
by utilizing the process
logic and data capture capability
of the ultrasonic
splicing systems.
Advanced ultrasonic plastic welders, such as the Branson GSX-E1, utilize electromechanical
actuators to precisely regulate downforce. This enables precise
plastic welds on even the most small and fragile parts. (Credit: Emerson)
Unlike other welding
processes, the process
heats but does not melt
the metal parts, and therefore
does not produce the
intermetallic compounds
that can lead to eventual
corrosion. Ultrasonic metal
welding is also used to
create tab and foil circuits
that are essential to energy
storage or batteries.
These batteries transmit
power to motorized or
heated components and
communicate visual data,
control signals or telemetry
essential to visualize,
and control robot arms
and effector functions.
Another key application
is for electrical connections
of fine wire assemblies,
e.g., 30 AWG Ag (silver)
coated Cu (copper)
stranded wire to a single
point contact for a sensor or actuator.
Both processes - ultrasonic plastic
and metal welding - also bond without
the need for additives or consumables.
So, in the case of robotic arms or surgical
end-effectors made of biocompatible
plastics, component welding does not
introduce the risk of external contaminants.
Both processes can also bond
extraordinarily small, fragile, or thin
components. Also, because ultrasonic
processes are so rapid, energy efficient
and repeatable in quality, it is possible to
fabricate high-quality, disposable end effectors
for RAS at a very predictable and
affordable cost.
RAS equipment and powered, implantable devices
rely
on small,
highly
reliable power connections,
often made with ultrasonic spot welds in
cleanroom environments. The battery weld connects
an aluminum tab with aluminum battery
foils and is just 2 × 2 mm. (Credit: Emerson)
Medical Design Briefs, October 2023
Laser plastic welding is a third assembly
process relevant to the production of
medical robots and end effectors. This
process is used to ensure the gentle,
flash- and particulate-free bonding of
plastics used in Class A aesthetic surfaces,
which include the exterior surfaces of
surgical robots, arms, and effectors. Laser
welding is accomplished by transmitting
a laser heat source through a transmissive
plastic part and into a laser
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absorbative plastic part, which softens
and begins to melt, enabling the two
parts to be joined under gentle compressive
force. Other benefits of laser welding
include hermetic sealing between
parts; the ability to join extremely thin or
fragile parts; and the ability to trace extremely
fine weld lines, which are essential
to joining parts with narrow or microfluidic
flow paths.
Another process essential to the production
of surgical devices, RAS effectors,
and even surgical implants is precision
ultrasonic cleaning. This method
uses an ultrasonic generator to produce
high-frequency energy pulses in aqueous
or solvent cleaning solutions in which
manufactured
components are immersed.
The ultrasonic pulses produce
cavitation, or fine bubbles that function
to remove manufacturing process contaminants
from product surfaces.
Improved Patient Outcomes
Together, assembly technologies like
these - ultrasonic plastic and metal
welding, laser plastic welding, and precision
ultrasonic cleaning - are helping
to shape the future of RAS systems and
instruments. They help solve a wide
range of assembly challenges and give
device designers a new degree of freedom
to explore innovative manufacturing
methods that can shorten development
times. For example, additive
manufacturing processes using 3D printed
tooling can rapidly prove out a tooling
concept, optimizing the design in
days rather than weeks.
The experience of technology providers
in developing minimally invasive surgical
instruments and RAS systems assembly
offers significant advantages for
the leading manufacturers of robotassisted
surgical systems. Adapting minimally
invasive surgical instruments for
end-of-arm robotic use will no doubt
lead to improved patient outcomes.
This article was written by Tom
Hoover, Business Development Manager,
Medical, Emerson Automation Solutions
- Americas, Brookfield, CT. His indepth
medical industry experience in all
aspects of product development and regulatory
compliance gives him a detailed
understanding of the challenges confronting
medical device manufacturers
and biotech firms. For more information,
e-mail tom.hoover@emerson.com
or visit www.emerson.com.
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Medical Design Briefs - October 2023

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