JEC COMPOSITES MAGAZINE - Issue #138 - January/February 2021 - 20

MANUFACTURlNG

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Natural fibres

Optimizing the machining of biocomposites
Lightweighting

Honeycomb cores for the automotive industry
Automation

Improving productivity and efficiency
with automated kitting system

MANUFACTURlNG natural fibres

Optimizing the machining of biocomposites
The work presented below focuses on a research project to fully exploit
plant fibres (flax, hemp, bamboo, etc.) for utilization as reinforcement
in industrial composite materials, which so far remains a major technological challenge.
Souhaïl El Bouami,
Teacher-researcher
Icam, Paris-Sénart

N

atural fibres such as flax, hemp and
bamboo are being used more and
more to reinforce industrial composites in order to reduce the weight, cost
and environmental impact of the products.
Under an environmental approach, they replace standard composites like those based
on polymer resins and synthetic fibres.
If their use remains a technological bot-

Example of different types of hemp based composites
that will be tested : Sandwich

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tleneck and a scientific challenge, it is due
mainly to the complex cellulose structure
of plant fibres from the leaves and stems
of cultivated plants. The research project
here proposes a behavioural analysis of
cross-sections of these biosourced materials, using a 2D orthogonal cutting process
and a 3D drill cutting process. The goal is to
understand the main physical mechanisms
that are activated by the process of removing matter from biocomposites.
A strong economic
and ecological interest
The use of plant fibres as reinforcement for
composite materials poses a real challenge
for manufacturers and researchers. Some
plant fibres have mechanical properties
that can compete with the synthetic glass
fibres currently used in industry. Plants
fibres also have the advantage of being an
environment-friendly solution, thanks
to their low environmental impact and
recyclability. However, it has been difficult
to harness manufacturing processes for
plant-fibre reinforced composites (called

	 jec composites magazine / N°138 January - February 2021

biocomposites), because these fibres are
natural, and therefore their properties tend
to be scattered.
Drilling into biocomposite/metal multimaterials creates a technical problem with
assembly. The drilling shows up various
types of damage in the structure that affect
the lifetime of bolted or riveted assemblies,
such as delamination within the composite,
formation of flash in the metal, differences in the diameters obtained in each
material or damage linked to the removal
of shavings, like thermal degradation in
the composite component. Drilling into
such hybrid materials therefore requires
a knowledge of the behaviour of each
material when cutting, the development of
optimized tool geometries (with or without coating), and a search for the optimum
cutting conditions.
The research carried out at the Icam engineering school included a preliminary state
of the art to present the intrinsic properties
of the plant fibres, in order to demonstrate
their mechanical behaviour compared to
that of synthetic glass fibres.
JEC COMPOSITES MAGAZINE - Issue #138 - January/February 2021

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