JEC COMPOSITES MAGAZINE - Issue #142 - September/October 2021 - 60

TECHNOLOGY inside the lab
Making thick-section composite components
The Exeter Composite Lab seeks to tackle several manufacturing barriers to the widespread utilisation of
thermoplastic composites, for thick-section metal replacement. Overcoming manufacturing barriers is not
trivial, often leading to far greater game-changing impact than certain blue skies research themes. This
work has led to the creation of novel thermoplastic composite manufacturing concepts challenging the
utility of both aluminium and thermoset resins.
F
rom a research perspective,
composites based on continuous
fibre prepreg laminates
are a mature technology - widely
used and supported by many
centres of academic excellence
across the world. The future horizon
for composite development
now lies in providing lightweight,
thick-section composite parts
rather than skin structures. This is
assuredly the next frontier growth
area for the wider application of
composites, where the mass scale
of production envisaged means
that the demand for recyclability
will be even more pressing. Exeter
has perfected a methodology for
reliably moulding thick-section
(>50mm) composite componentry,
using discontinuous PEEK
carbon fibre prepreg tapes, and
thereby allow the use of composites
in a whole range of new application
areas.
Industrial partnership
Working with industry to find solutions to real-world needs is central to Exeter's approach,
characterised by multipartner initiatives developing thick-section parts, alongside
Meggitt PLC - a T1 airframe parts maker, in collaboration with Leonardo and
Boeing, where the demonstrator part was a full composite version of the AW189 helicopter
wheel. The lab also partners with raw material suppliers Victrex PLC, trialling
commercial and developmental grades of PAEK plastics, and Toray - a global composite
raw materials manufacturer of PEEK/CF tapes to specification. This includes cut
tapes manufactured from Victrex PEEK grades including trial batches of developmental
materials, plus uncut rovings, allowing Exeter to experiment with cutting angle and
length factors. Further collaborations involving Chinese automotive giant Geely and
Bentley motors UK also focused on thick-section PEEK composites for metal replacement
in electric vehicle
R&D approach
Exeter's research seeks to solve several manufacturing
barriers to the widespread utilisation
of thermoplastic composites, where practical
solutions would have a real-world impact, in
providing a viable lightweight and recyclable,
composite system at component level for metal
replacement, with important commercial implications,
as evidenced by the level and depth
of industrial support and interest in this area.
Successful manufacturing routes are based on
a fundamental understanding of the behaviour
of materials during processing, leading to innovations
in equipment functionality, and a design
overhaul of compression moulding tooling and
also innovations in post-processing operations
of moulded parts.
Exeter Composites Lab
is part of the
" Exeter Technologies Group " (ETG)
a strong team of
15 Materials Scientists.
Key research aspects include:
- Perfecting a methodology for reliably moulding
thick-section (>50mm) composite componentry,
using discontinuous PEEK carbon
fibre prepreg tapes, and thereby allowing the
use of composites in a whole range of new ap60
jec composites magazine / N°
142 September - October 2021
plication areas.
- Researching this new manufacturing route
via the use of pre-moulded " pre-charges " ,
which will simplify manufacture and remove
the barriers to rapid volume production, similar
to the advent of prepregs and SMC in the
1970's.
- Enhancing the available mechanical properties
of thermoplastic composites (TPC)
in the form of discontinuous tapes through
targeted fibre orientation, thus offering an
alternative to thermosets with properties to
rival aluminium. Targeted fibre orientation
using strategically-placed charge packs delivers
exact stiffness/strength properties in key
regions of the moulding.
- Exploring the inherent recyclability of TPCs
without any material wastage or costly recycling
steps.
- Providing the requisite materials testing evidence
describing the extent to which thermoplastic
composites are " healable " after
damage, are remouldable, can be reshaped
and reused in entirely different applications.
JEC COMPOSITES MAGAZINE - Issue #142 - September/October 2021

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #142 - September/October 2021
