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At 23 metres to 33 metres long and up to 2.5 metres wide, the
top wing skins on the Airbus A380 super-jumbo, due to make its maiden flight in
2005, will be the largest components ever produced by the creep-forming process.
The first set of wings was recently completed at the company's site at
Broughton, North Wales.
The tooling to produce these components was designed by South
Yorkshire engineering consultancy Bennett Associates using one of the first
releases of CATIA version 5 developed by Dassault Systhmes. While Airbus itself
had standardised on CATIA version 4, Bennetts opted for version 5 because of its
greater flexibility when handling large quantities of data and its ability to
run customised programmes.
The eight forming tools designed by Bennetts, one for each skin
panel, involve eight heavy-duty steel bases on to which some 280 ribs are
mounted, which produce the finished shape required. This concept allowed a large
proportion of each tool to be manufactured while the final wing designs were
being completed and will also allow any future changes in design and materials
to be accommodated relatively quickly and economically. Each item is about 40
metres long and weighs 50 tonnes.
The wing data supplied by Airbus from which Bennetts had to design
the tooling involved some 500,000 reference points for each surface shape, one
cloud defining the global surface and a second the edges.
In order to enable the CATIA software to handle this quantity of
data, Bennetts used the product's Application Programming Interface facility to
run customised programmes developed in-house to convert the data into workable
files.
Visual Basic software was used to read all the points, sort them
and do some smoothing and interpolation, and a second analysis output file was
then produced to compare the created surface with the original data. Having
checked that the profile and the surface were consistent, the surface was
trimmed back to its finished shape, using the outline point cloud provided again
by Airbus.
Using CATIA in this way, Bennetts were able to generate wing
profiles and tool designs very quickly. Once final designs were complete,
comprising file sizes of some 2.5Gb in memory, the programme was used to output
manufacturing information to the laser profiler producing the ribs, around 280
for each tool and each one unique -- that would determine the finished wing skin
shape.
Eight weeks after the final designs had been received from Airbus,
tooling was in place at Broughton, ready for production testing to start.
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