Materials analysis of
the 787 exemplifies
the growth in composites
use
Out of Autoclave -
Resin Infusion
• Enables complex and
integrated net shape parts
to be made in one piece.
• Tailored fibre placement
brings local property
improvement
• Creates opportunities for:
Process improvements –
(simulation, control)
Preforms (automation,
lower cost, textiles)
Tooling (reduction in cost
and complexity)
november 2007
resurgence of interest in these materials from the aerospace
sector, coinciding with the development of advanced resin
systems. One attraction is that autoclaves are not needed.
‘Autoclaves are expensive, take up a lot of space, use a lot
of energy, need a nitrogen supply to pressurise and require
long lead times’ observes Sdao. Also there is an anticipated
global autoclave capacity problem, so CAMTec is matching
projected industry needs by looking at ‘out-of-autoclave’
processes and materials, such as resin transfer moulding
(RTF). This process locates a dry carbon fibre pre-form
inside a mould and then pumps in epoxy resin. The fibre
can be placed to enhance local properties, and complex,
near net shape parts made in one piece. Another technique
under investigation entails putting a ‘sock’ over a form tool
and creating for example a wing by resin injection: ‘You’re
getting away from tape laying and pre-pregs which must
be stored at –20˚C; it’s the kind of thing we can help with.’
This does raise the question as to whom specifically
AMRC and its divisions are helping, and whether there are
ever any conflicts over IP. AMRC was founded on a
collaboration between Boeing and the University of
Sheffield – and there are usually Boeing people around -
but there are projects for Airbus. ‘It works fine when we
stick with specific projects’ says CECA business
development manager Jim Heley, adding that they are
sensitive to confidentiality requirements. ‘But if you
develop a technique on one project you’ve effectively
learned how to do something better and faster’ observes
Conrad Sdao; ‘so as a team you’ve got the knowledge, and
you can’t then take it out of your head.’
‘In fact they tend to feed off each other to some extent’
says Heley: ‘and one of the Boeing guys has said “what’s
good for Airbus is good for manufacturing”. But if one of
our partners wanted exclusivity we’d give them that.’
AMRC has similar issues with other competing partners
such as Rolls Royce and GE Aerospace, and deals with them
in much the same way, allocating costs on specific projects
and preserving confidentiality as and when required.
Heley points out that CECA’s focus on assembly doesn’t
really raise any such issues: ‘Boeing and Airbus compete on
building efficient aircraft, not on how they are put
together, so both companies are ok to a degree.’ One of the
main drivers for all aircraft builders (going back to that
Gulfstream) is reduced parts count. ‘With an aircraft you
are talking millions of parts, but you can halve that when
you use composites, so assembly gets easier right away.’
Responding to commercial pressures
CECA has been going for about a year, building expertise
in metrology, assisted assembly, automation and robotics.
It’s a Higher Education Initiative funded to the tune of
£4.2million over two years and operating through
Sheffield, Nottingham and Loughborough Universities.
Loughborough is concerned chiefly with simulation,
Nottingham with high volume (eg electronics) assembly;
Sheffield is the lead organiser, working on physical
assembly of low volume, larger structures.
‘We are focusing on metrology-assisted assembly and
automation, and process flow modelling’ explains Heley. A
project addressing sub-structure drilling highlights some
of the commercial pressures at work. ‘When you are
working in places which are difficult to access, currently
any holes must be drilled manually.’ There’s a strong
imperative to automate such processes, driven by
commercial as well as health and safety issues (for example
RSI). Another current exercise, a line with integrated
vision systems, is using flatpack furniture kits to examine
some of the problems of automated assembly. This is not so
bizarre as it sounds, once you realise that the model reflects
situations which can arise in standard engineering
situations ie too many or too few of certain components
within a family of parts, over or under-size components.
‘Assembly is a massive subject’ continues Heley; ‘ a lot of
people are having parts made overseas, but are bringing
them back to the UK for assembly, and we are in a good
position to help them.’ CECA is looking especially at
customised, high mix/low volume production and is
therefore focusing on intelligence, flexibility and control -
‘getting systems to talk to each other’.
And we are looking for people to work with us; as part
of the funding agreement there are criteria we must meet -
KPIs put in place by the DTI, for example “significantly
assisting UK companies make step changes in assembly
techniques”, and “responsibility for offering training in the
latest techniques.” We are reaching the stage where we have
something to offer.’
CECA’s partners include Metris: ‘Aerospace is one of
their core markets, and their equipment is very useful for
customised assembly applications.’ A good example is the
use of ‘GPS’ systems - which effectively turn the building
into a CMM – on 787 fuselage assembly at Boeing. A
current CECA project which aims to improve that
technology is being assisted by a Boeing assembly specialist
on secondment from the Phantom Works. ‘That’s saving us
time; we have a lot of Boeing people over here providing
guidance, with wide knowledge of what’s in the future,
and the technologies we should be involved in.’
Vector 31: it sounds mysterious but the technology being
developed has enormous practical potential and could
ultimately begin to shape UK manufacturing capacity. As
for the Gulfstream fuselage? Well, every home should have
one - it’d make a great garden shed; not quite wide enough
for a snooker table though……..
www.amrc.co.uk
aerospace
MWP
45
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