For example the wing shells for the Airbus A350 XWB series of aircraft cannot undergo more than 3 mm (0.118 in.) deflection over their 30 meter (98.4 ft.) length during manufacture, assembly and transportation.
The problem with producing such large jigs and fixtures from metal is that in order to deliver the very low expansion and deflection properties that are required, the jigs are both very expensive and very heavy – more than 10 tonnes (11 tons) for a 30 x 15 meter (98.4 x 49.2 ft.) long wing jig.
Acrosoma. (Lokeren, Belgium), who specializes in the manufacture of high-performance composite structures for road, wind energy and aerospace applications, has made a significant technical breakthrough by developing tri-dimensional sandwich composite alternatives that deliver even better deflection figures yet at the same time weighs a mere 4 tonnes (4.4 tons).
Already the company has received an order by KUKA Systems for five 30 x 7.2 meter (98 x 23.6 ft.) wing jigs for the Airbus A350 XWB program and has developed an assembly jig for Thyssen Krupp System Engineering for the manufacture of the outboard flap for the A350 XWB.
The jigs are fabricated using tridimensional sandwich panels that feature a Divinycell P structural core. Unlike conventional sandwich structures, the two skins and the core of an Acrosoma panel are stitched together to further optimize its stiffness, peel strength and dimensional stability.
The panels are produced on a fully automated production line that was designed and built by the Acrosoma engineering team. Diab core is pulled through the line, dry fibers are applied to the top and bottom faces and the whole assembly is stitched together. The resulting ‘package’ then enters a resin-injection chamber. Finally it passes through a curing die to complete the process. This unique process allows Acrosoma to produce 2.8 meter (9.2 ft.) wide panels of virtually any length on a continuous basis at a rate of 150 square meters (1,615 sq. ft.) an hour. Such is the flexibility of the process that Acrosoma can use a variety of reinforcements (glass, aramid and carbon) as well as both vinylester and epoxy resins.