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The answers to the assembly constraints of
new composite structures, the requirements of
reliability and the shorter assembly time required
by the division’s customers have led to the launch
of two major projects at LISI AEROSPACE. These
projects have a global reach and have helped to
change the great historic families of HI-LOK™/
HI-LITE™ and PULL-IN™/PULL-STEM™ products.
These projects, which have involved input from
most of the sites, have strengthened the Group’s
innovation dynamics and increased the internal
skills in terms of structuring and management of
multisite R&D projects.
The first results of this re-engineering process
were achieved in 2011. The HI-LOK™ and
HI-LITE™ systems have been fully redesigned
to fit composite assemblies. The integration of
the ASTER™ system, the use of HI-KOTE™ NC
chromate-free coatings and the addition of new
combinations of surface treatment have kept
the reference level of these products, adapting
them to hybrid and composite structures. The
development of chromate-free treatment also
reduces the environmental impact.
Optimizing the installation
time of high interference
fasteners
The range of high interference fasteners PULL-
IN™ and PULL-STEM™ fasteners has also been
renewed and improved as part of this research
program. These fasteners are needed to ensure
the structural integrity of assemblies subject
to fatigue in the metallic or strongly loaded
hybrid junction areas. In their capacity as
reference products for this type of application,
the PULL-IN™/PULL-STEM™ systems should
progress in terms of ergonomics, optimization
of the installation time and reduction of
their environmental impact to maintain their
competitive edge. The new generation of
PULL-IN™ fasteners was designed with a shorter
thread to reduce the weight and installation time
on the assembly lines of the Airbus A350. A new
application of the PULL-STEM™ high interference
fasteners in Inconel has also been developed
with Boeing by LISI AEROSPACE’s Canadian plant
for the B787. Finally, a swivel version completes
the range to meet the assembly requirements on
slopes for our customers Embraer and COMAC.
Newpressure locks
for A350 Engine pylons
The pressure locks are security features that allow
opening a door to prevent damage due to overpressure
in a closed compartment (pylons, fairings, engine
compartments). The requirements are more and more
precise, both in terms of triggering thresholds and the
efforts applied to the locks and the entire door. The
kinematics and technology choices had to be reconsidered
to provide a reliable solution. The choice of a dual-spring
and an innovative cam trigger allowed our engineering
office in Vignoux-sur-Barangeon to specifically address
the requirements identified by Airbus to the pressure
doors on Airbus A350 pylons.