JEC COMPOSITES MAGAZINE - Special Issue Composites for mobility - May 2020 - 44

APPLICATION recycling

Using recycled composites
for an electric bike wheel hub
To reduce the footprint of daily mobility, Cogit
Composites conducted a project that focused on the
use of composite production waste to develop a new
electric bike wheel hub with a specific design.

hermoplastic polymers are increasingly used as matrix materials in long-fibre composite
materials. This implies dealing with
more production scrap in the short
term and more end-of-life parts in the
long term.
There is currently no easy way to separate carbon fibre from the matrix in
unused composite materials, so that
composite waste is buried or burnt,
generating toxic fumes, greenhouse
gases or water and soil pollution. To
comply with the latest EU regulations, such as the Waste Framework
Directive [1] and the Directive on
End of Life Vehicles [2], recycling and
re-use have to be integrated into development plans.
Recycling method
The recycling method commonly
used in the plastics industry involves
a shredding step followed by a grinding step, resulting in a finer material
that can be used as a reinforcement
in thermoplastic injection processes.
Unfortunately, this leads to low re-

Stamped part

inforcement levels compared to the
initial part. An alternative solution is
to chop the composite parts or production scrap (Figure 1) into not-sosmall compounds (Figure 2), usually
25-50 mm long and 2-6 mm wide,
and to use them as a primary material
in compression moulding processes.
For 15 years, thermoplastic composite materials and processes have been
at the core of COGIT Composites'
strategy. Working on compression
moulding, stamping and over-injection/moulding, especially for aeronautic applications, the company rapidly thought it could use its advanced
skills to produce parts requiring the
same level of quality but in totally different fields such as medical, luxury
or sports products. The aim was not
to manufacture just simple products
but to be eco-friendly. So the decision
was taken to use production waste to
reduce the footprint of daily mobility.
This is how a new electric bike wheel
hub was developed.

Chopped composite

jec composites magazine / SPECIAL ISSUE Mobility / May 2020

Christophe Roua,
CEO, Strategy and R&D
Cogit Composites

Technical feasibility
A specific design was created to replace
the existing aluminium part (Figure
3) with a lighter wheel hub (Figure 4)
while ensuring complex shape forming, structural and kinematic functions
and a high-end perception by the final
customer.
The team first applied compression
moulding design rules to evaluate the
technical feasibility and properly integrate original functions. Parallel to this
engineering stage, a collaborative R&T
project called RTL3 (2012-2015)
was conducted with the University of
Orleans and the Plasticompo platform
in the centre of France. The goal was
specifically to define the best com-

Fig.3: Main body of Aluminium
Wheel Hub

Fig.4: Main body of reused composite Wheel
Hub

JEC COMPOSITES MAGAZINE - Special Issue Composites for mobility - May 2020

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