JEC COMPOSITES MAGAZINE - Issue #122 - July 2018 - 29

Full out-of-autoclave thermoplastic welded airframe

Overmoulding tool by COMPOSE and TP Frame by
PORCHER industries & CETIM.

Finally, the innovation reduces CO2 and
NOx emissions. This project highlights
the wide application potential of thermoplastic composites in primary airframes.
The material's high mechanical performance combined with new assembly
technologies such as induction welding
promise major weight savings that will
result in aero-engines with reduced fuel
consumption and emissions (CO2 and
NOx).

Porcher Industries developed two
different products: 3K woven carbon/
PEKK and 12K woven carbon/PEKK
laminates. The project's carbon/PEKK
laminates were the result of two key
Porcher Industries innovations focused
on enhancing the adhesion, impregnation and consolidation of the carbon/
PEKK laminate: a new surface modification of carbon fibre and a specific
weaving format for the heavier 12K tow
with low crimp. Thanks to these technical
breakthroughs, it was demonstrated that
12K carbon/PEKK laminates exhibit the
same performance level as more traditional 3K carbon/PEKK laminates.
Sintex NP's contribution to the innovation was the one-shot production of a
thermoplastic overmolded part based on
a new thermoplastic PEKK matrix. The
company developed an overmoulding
process that combines CFRP for high
performance and a short fibre-reinforced
thermoplastic to reach complex geometries and add functions to the part. This
process combines CFRP stamping and
injection technologies.

This technology significantly reduces finishing operations and provides a solution
for advanced feature integration, which is
currently inaccessible for stamped parts.
The company's ambition for the future
is to develop systems (industrial means)
for local overmoulding operations on
large parts.
CETIM contributed to the Arches Box
TP project through the manufacture of
thermoplastic composite frames by a
forming process. The innovation deals
with the use of carbon/PEKK and a
stamping set-up for a short-radius frame.
Aviacomp developed and produced all
the thermoplastic-matrix omega stringers for the Arches Box TP project using
a high-performance TP composite with
a low maturity level commonly named
PEKK.
Composite Integrity - Institut de
Soudure Group developed an induction
welding process for carbon UD tape,
which is a more complex process than
for carbon fabrics. The process involves
no added interface between the parts to
be welded. Welding can be done using a
laminate that includes LSP (slit copper
foil for lightning strike protection).
Thickness evolution can also be integrated in one of the assembly's laminates to
optimize the thickness and weight. The
key element of the technology remains
the coil, which is specifically designed for
the welding configuration.

Compose Tool demonstrated the technical feasibility of functionalizing stamped
parts using a local overmoulding step.
N°122 July 2018

More information:
www.stelia-aerospace.com

More information
Benefits of the
Acrosoma® panels
- High strength-to-weight ratio
- Excellent insulation
- Uniform quality due to consistent, continuous production
- High impact resistance
- Durability and reparability
- No delamination

/ jec composites magazine

Feature Aerospace

Another positive factor is the limited
consumption of materials and chemicals.
The overmoulding process allows the
production of a single integrated multi-functional net-shape part, avoiding the
use of sealants for the assembly of different parts and a better buy-to-fly ratio (no
machining after injection).
The high-performance thermoplastic
technologies developed for this project
allow the full automation of processes
(AFP, stamp forming, dynamic induction welding, overmoulding). These
technologies have a high added value and
will require major research and equipment investments that will help ensure
the long-term economic competitiveness
of the aeronautical industry, academic
laboratory training and education for the
next decades.

The partners involved in the project
As part of this project, Stelia Aerospace
developed and integrated in a full-scale
realistic and typical airframe demonstrator six thermoplastic technology bricks
mandatory for a low-cost, high-volume
fuselage: automated fibre placement
(AFP) of slit thermoplastic tape, automated fibre placement of a lightning
strike protection, dynamic robotic
induction welding of TP stringers, a
hybrid TP structure produced by overmoulding short and long fibres, and fast
stamping of stringers and frames with
out-of-autoclave consolidation. This
R&T development highlighted many
industrial and technical issues associated
with thermoplastics, giving a better
vision of the remaining industrial technology challenges for a serial application.

29
http://www.stelia-aerospace.com
Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #122 - July 2018
