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used in conjunction with multi-layer reinforcements, such as NCF fabrics, the process can be highly costeffective.
HexPly® 8552RFI and HexPly® M36 are Hexcel’s recommended systems for RFI. Both are fully compatible
with HexFlow® RTM6, making them ideal for RFI/RTM processing. Both products are supplied as a film for
use with dry fibre/fabric preforms or as semi-preg, where the resin film is supplied pre-positioned on top of
the fibre-reinforcement layers, ready for consolidation by the customer.
Resin Film Infused engine inlet outer barrel panel Airbus A380 fixed trailing edge
lower panel (GKN Aerospace)
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ADVANCED FIBRE-REINFORCED MATRIX PRODUCTS FOR DIRECT PROCESSES
Benefits of RFI:
• Particularly suitable for large composite structures
• Very fast deposition rates achievable
• Adaptable for a wide range of textile forms (2D & 3D woven non crimp fabrics)
• Full infusion of thick reinforcements
• Flexibility to use non-autoclave processing
Key Resin Attributes
HexPly® 8552RFI with greater toughness, is based on Hexcel’s widely qualified HexPly® 8552 resin system.
HexPly® M36 is a lower density matrix leading to an average 3% weight saving at the same fibre volume
content (versus other resin systems)
Both products provide:
• Ideal tack and viscosity for RFI, semi-preg and prepreg
• Excellent mechanical properties (toughness, hot wet open hoe compression)
• Low exotherm for ease of manufacturing thick structures
• Capable of standard autoclave or vacuum assisted infusion followed by oven cure.
REINFORCEMENTS FOR DIRECT PROCESSES
Hexcel is a leading manufacturer of woven, unidirectional and multiaxial reinforcements for composites, in
glass, carbon and aramid fibres, and hybrids. We have applied our experience and knowledge of fibrereinforcements
to develop a range of textile options that are ideal for Direct Processes such as RTM, RFI
and LRI.
HexForce™ Woven Fabrics
Fabrics consist of at least two threads which are woven together; the warp and the weft. The weave style
can be varied according to areal weight, crimp and drapeability. Low crimp gives better mechanical
performance because straighter fibres carry greater loads. A drapeable fabric is easier to lay up over
complex forms.
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There are three main weave styles:
Balanced woven fabrics provide strength and stiffness in two directions. They provide very good handling
characteristics and good drape. There is a wide range of weave styles and it is possible to mix fibres to
provide hybrid fabrics. Standard HexForce™ fabric weights range from 20 to 600 gsm.
HexForce™ Multiaxials and Non Crimp Fabrics
Multiaxial reinforcements,
also known as non-crimp
fabrics, are layers of
unidirectional fibres that are
assembled and stitched
together. They provide
strength and stiffness in
multiple directions
depending on the controlled
fibre orientation. The
weight distribution in the
fabric is optimised and it is
possible to mix fibre types.
The non-crimp concept
allows in-plane mechanical
properties to be enhanced,
such as tension and
flexion. There is less
waste for complex lay-ups.
Lay-up time is also
reduced by using thicker
materials. Processing
costs are reduced and
heavy tow fibres can be
used.
Diagram showing possible fibre
orientation of a multiaxial reinforcement
Production of HexForce™ multiaxial
reinforcements
Eg fabric reference 43 193 G926 G 1157
Eg: G 1157
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ADVANCED FIBRE-REINFORCED MATRIX PRODUCTS FOR DIRECT PROCESSES
Woven Preforms
For many years Hexcel has offered specialty reinforcements that meet specific geometry requirements,
such as woven socks for radomes, woven spirals for windmill blade couplings and 3D fabrics for carboncarbon
applications. The development of Direct Processes has increased demand for dry preforms that
are supplied ready to be placed into a mould tool.
Novel Technologies for Dry Non-Woven Preforms
As part of its investigations into new cost-effective methods for manufacturing high performance composite
parts, Hexcel has developed Dry Fibre Placement Technology. This technology uses an automated robotic
process to lay-up dry fibre, or UD tape, on a tool, to manufacture preforms for injection and infusion
processing.
The main advantages of this technology are:
Concept: Performance/weight ratio optimisation
Automated, optimised and repeatable yarn placement
Flexibility for geometry modification
Qualification: From yarn to preform
Single material concept
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