THE SINGAPORE ENGINEER - Institution of Engineers Singapore

COVER STORY
WIDE CHORD FAN BLADE
MANUFACTURING FACILITY
Super plastic forming process at the Wide Chord Fan Blade (WCFB) manufacturing facility.
The Wide Chord Fan Blade (WCFB) manufacturing facility
at the Rolls-Royce Seletar Campus is the group’s first facility
outside the UK to manufacture hollow titanium WCFBs - based
on unique technology that has played a key role in the success
of the Trent aero engine family.
This facility has been purpose-built to increase efficiencies and
provide additional capacity to the group’s Barnoldswick factory
in the UK.
The Seletar facility is designed to simultaneously produce
WCFBs for multiple Trent engine types. Initially, it will produce
WCFBs for the Trent 900, beginning in mid-2012. At full capacity,
the facility will be able to produce 6,000 blades per year.
WCFB
The hollow titanium WCFB was pioneered by Rolls-Royce
and introduced into service in the 1980s. It has since set new
standards in aerodynamic efficiency and resistance to foreign
object damage.
The blade’s hollow design allows significant weight saving
of around 30% to be achieved in the fan blade, the fan disc
structure, and containment features, which greatly improves
performance and fuel efficiency.
Moving a tonne of air per second, the fan produces over 80% of
the engine’s thrust.
The largest Rolls-Royce WCFB currently in service is on the
Trent 900 for the Airbus A380. A total of 24 blades are needed
to complete one Trent 900 engine with a fan diameter of 116
inches. The Trent 1000 engine for the Boeing 787 Dreamliner
requires 20 blades and has a fan diameter of 112 inches.
The manufacturing process
In total, about 80 complex processes are involved in producing
the hollow titanium WCFB, which result in their very lightweight
but exceptionally strong design.
The blades feature an internal structure, created through a process
during which three sheets of titanium are formed, representing the
two outer skins and the internal corrugated structure.
An inhibitor is applied to define the internal structure before
the three pieces are bonded in a high temperature pressure
vessel. This is done in an ultra-clean production facility through
a process of diffusion bonding, for which Rolls-Royce has more
than 60 patents registered, worldwide.
Finally, the blade is twisted and the cavity is inflated at a very high
temperature using an inert gas in a shaped die to yield its final
aerofoil shape.
Using millions of data points from advanced cameras, the dimensions
of each blade are measured to the accuracy of 40 microns.
The WCFB is subjected to linishing.
The hollow titanium WCFB is lightweight but exceptionally strong.
12 THE SINGAPORE ENGINEER April 2012