DONCASTERS REVEALS PRODUCTION BREAKTHROUGH
lip skins & beyond
Doncasters has been using electroforming for more than 13 years,
predominantly as erosion shields on rotor blades. Earlier this year, the
company unveiled a breakthrough use, as Andrew Woods, business
development manager for Electroform & Airmotive, explains
Electroforming is a proven production-
based additive manufacturing process
used to physically deposit metal in a
controlled process in microscopic layers to
highly precise geometries.
This year, at the Farnborough International
Air Show, Doncasters unveiled its pioneering
project that, it said, will “take the industry by
storm” – a fully electroformed leading-edge
erosion shield for an aerospace engine inlet lip
skin on a passenger jet.
Not a new process, electroforming has
been used for well over 100 years, but in
terms of aerospace applications, it is a relative
newcomer. The current main use of
electroforming is for rotative fi xed components,
that protect the leading edge of composite
structures. Electroformed parts are form-fi tting
and stress-free products that do not twist,
warp or spring back. They are prepped, bonded
and then mechanically fi xed to components.
Nickel-based alloys are the most popular
choice of material, due to their favourable
mechanical properties. Nickel-cobalt, in
particular, has internal stress low enough for
the electroforming process while enabling the
creation of an alloy-enhanced fi nished part.
The main application of nickel-cobalt parts is
for erosion protection. Since 2005, Doncasters
has been developing helicopter blades through
the process of electroforming to protect them
against premature wear and damage. For
example, bird aircraft strike hazards pose a
threat to composite blades. And while the
number of major accidents involving civil
aircraft is quite low, 65% of bird strikes still
cause damage to the aircraft.
Nacelle lip skins, just as with rotor blades,
need to be able to operate in harsh
environments and be produced to tight
tolerances. They are traditionally created by
spin-forming aluminium alloys, where a blank
of fl at material is rotated on a spinning
machine and material ‘pushed’ over a forming
mandrel. During rotation, heat is applied to the
material by a gas torch.
Such spun-formed parts require signifi cant
post-processing steps, including heat treating
for stress relief, burnishing and machining.
These parts are produced in a full
circumference, single piece, but operators may
require the lip skin to be in multiple sections to
allow for removal, and replacement of
damaged sections during the life cycle. This
can add further machining and stress relief
steps to assure that the segments do not
deform or spring back during installation.
Doncasters already produces a one-piece
inlet lip skin for a production turboprop engine.
The electroformed process was adopted to
replace a multi-piece sheet metal design that
was mechanically fastened to the engine
nacelle. The electroformed lip skin precisely
fi ts the contour of the nacelle and proved to be
more cost-effective for part production and
While this has proved successful for many
years, the Doncasters R&D team has identifi ed
three major benefi ts of switching to the
electroforming process: cost saving:
October 2018 www.machinery.co.uk @MachineryTweets
Kyal Machine Tools Limited.
The Settling Rooms, Springfield Street.
Leicestershire LE16 8BD
Tel No. 01858 467182
A part is removed from a mandrel. More parts
can benefi t from this electroforming process,