Page 4 - Industrial Technology EXTRA - 10th August 2020

ELECTRIC MOTORS...

Autoclavable DC motors ease

surgical power tool design

Electric motors have brought many advantages to powered hand tools, however
there are various approaches for design engineers to consider when selecting a

motor for surgical instruments. Jamie Gewirtz, R&D manager for surgical motors
at Portescap, looks at some of the design challenges and discusses considerations
for the selection of the most appropriate electric motor
ith manufacturers of powered
surgical tools having now switched,
almost universally, from pneumatic
Wto electric operation, selection of the
most appropriate electric motor has become a key
design consideration. The likes of arthroscopic
shavers, sagittal saws, oscillating saws, orthopaedic
drills, medium- and high-speed drills, wire drivers
and surgical staplers all make stringent
requirements on the motor, but beyond that there is
the need to take into account sterilisation
requirements.
The most common sterilisation method used in
hospitals is autoclaving, also called steam
sterilisation. Here, surgical hand tools are exposed
to high levels of humidity, temperature and pressure
for several minutes in order to render the instrument
sterile. Most autoclaves also have additional
vacuum cycles to facilitate steam penetration and
kill bacteria, viruses, fungi, and spores that can hide
inside the tool. available to the designers of such tools? With the
This repeated exposure to autoclave conditions sterilisation process so demanding, one approach is
is what gives manufacturers of powered surgical to design single-use tools that are simply disposed
instruments the most problems when it comes to of after surgery. These can use an inexpensive DC
electrification of the tools. So what options are motor and plastic components. However, any initial

August 2020 • INDUSTRIAL TECHNOLOGY EXTRA! • p4