TECHNOLOGY NEWS
Heat-based disbonding technology
promises to transform composite use
Researchers anticipate industrial scale applications
JON EXCELL reports
Technology demonstrated by
researchers at the National
Composites Centre in Bristol
promises to make it easier to
dismantle, repair and recycle
composite parts.
Developed in collaboration
with a team from Oxford Brookes
University, the technology - which
involves the use of carefully
modifi ed structural adhesives –
enables composite structures to be
separated (or disbonded) quickly
and cheaply using a simple heat
source.
The research could have
a transformational impact on
the design, use and end-of-life
recycling of products including
cars, aircraft and wind turbines.
Project leader, NCC research
engineer Lucy Eggleston, said
that the group has explored the
use of two specifi c off -the-shelf
additives which can be added to any
structural adhesive.
The fi rst of these additives,
expandable microspheres,
have been explored before for
disbanding applications, but never
for industrial scale applications.
These are eff ectively thermoplastic
Engineers at igus have joined the
manufacturing effort to produce
personal protective equipment for
frontline healthcare workers.
As part of an effort coordinated
by the National 3D Printing Society
(N3DPS), the polymer bearing
specialist has repurposed an area of
its Nottingham offi ce for the assembly,
packaging and despatch of face shields
to UK hospitals.
The N3DPS protective Face Shield
bubbles containing hydrocarbons
with relatively low boiling points,
explained Eggleston. “When they’re
exposed to heat the thermoplastic
bubbles become malleable and
stretchable and the hydrocarbons
boil and expand. That causes the
whole bubble to expand which
when used as part of a joint causes
two surfaces to push apart from
one another and breaks apart an
adhesive bond.”
June 2020 / www.theengineer.co.uk 8
A company that proposes storing
and releasing energy with winches
and weights in mineshafts is set to
build its fi rst demonstrator project
in Scotland.
Edinburgh start-up Gravitricity
has signed an agreement with Forth
Ports to build its fi rst demonstrator
on land within the Port of Leith.
Work will begin on the £1m project in
October with plans to be operational
by late December.
The 16m high rig will use the
port’s electrical network and grid
connections and will be used to
demonstrate the speed of response
of their energy storage system.
Gravitricity’s energy battery
works by raising multiple heavy
weights – totalling up to 12,000
tonnes – in a deep shaft and
releasing them when energy is
required. It plans to roll out its
technology in disused mine shafts
globally.
The demonstrator at the Port of
Leith will allow the technology to be
trialled on a smaller scale, utilising
an above ground structure.
The Gravitricity project is
supported by a £640,000 grant from
Innovate UK . JF
Read more at
www.theengineer.co.uk
The second additive,
expandable graphite, which has
never before been explored for this
application, works in a slightly
diff erent way, she added: “We use
these stacks of graphite with really
thin carbon layers between these
graphite plates. When they’re
exposed to heat those oxidise
and that causes expansion. That
expansion forces to joined parts
apart from each other.”
During trials the team
demonstrated potential
applications on a ba ery box
supplied by Williams Advanced
Engineering. “We designed three
diff erent features that would be
industrially relevant, bonded them
together and demonstrated that
application of this technology
by releasing all of those diff erent
parts,” said Eggleston. A number of
diff erent heat sources were trialled,
including a bespoke induction
coil that could also be used on
a disassembly line, an infrared
lamp, a heat gun and an oven. The
induction coil method was able to
disbond a joint in just six seconds,
whilst the IR lamp and heat gun
took slightly longer.
IGUS JOINS COVID-19 ENGINEERING RESPONSE
GRAVITRICITY
SET TO LAUNCH
STORED ENERGY
DEMONSTRATOR
JON EXCELL reports
is made with two parts: a screen and a
3D printed mount. The screens can be
made from clear PVC binder covers with
a 4-hole punch, using an A4 ISO-888
hole confi guration. The Mounts can be
printed in under one hour and can be
stacked to produce multiple mounts
from a single print. With no requirement
for fi bre elastic to secure the shield, it
is claimed to be easier to sanitise than
other devices.
The face shields are currently NHS
accepted and the group is working on
CE approval.
Commenting on igus’ involvement
in the project, the company’s
UK MD Matthew Aldridge said:
“Once again, the manufacturing
industry has showed its resilience
and adaptability by rising to the
challenges set by the Covid-19
pandemic. We are proud to be part
of this, within a week we redeployed
a section of the igus factory in the
UK to assemble face visors, and are
continuing to supply hundreds every
day, direct into the NHS and other
frontline areas.”
/www.theengineer.co.uk
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