BAe Systems has upgraded its Airbus UK anodising facility at its Broughton site in Chester, UK, because it was struggling to keep up with the demand for Airbus aircraft wing skins. The company believes that the new facility is the largest and most modern of its kind in the world. It is capable of fully automatically anodising components 34m-long, 1.5m-wide and 4m-deep, weighing up to 4t and at 35 loads per day.
The contract for the automatic handling facility was awarded to Luxembourg-based CTI Systems S.A., which had previously designed and installed systems for use in the aircraft and aluminium industries. The contract required CTI to collaborate with BAe on the design of the equipment and be able to deliver some of it at short notice.
The equipment delivered by CTI Systems consisted of two fully-automatic 40m-wide cranes, a 40m-wide automatic transfer car, eight 37m-wide aluminium flight bars, a 40m-wide manual crane and three 120m runs of underslung crane rail. All this equipment was manufactured by CTI at its factory at Clervaux in Luxembourg.
One of the conditions of the contract was that the manual crane had to be installed and running within 12 weeks of the order. The reason for this was that the crane was to be used in the installation of 15 anodising tanks and their associated pumps, pipes, ducts, control panels and other ancillary equipment. The manual crane was also fitted with a permanent, full width work-deck with handrails and manual controls. This was so that it could be used as a moving scaffold during the installation of all the services above truss level, such as lighting and sprinklers, and could also be used for maintenance of these items. The manual crane was controlled by its own PLC, and was also integrated with the control system of the automatic cranes to prevent it straying into their path.
The underslung crane runways are CTI’s patented Tarca monorail, which is a special I-beam fabricated to a high tolerance, using a high carbon steel running rail flange, mild steel web and a mild steel top flange. This rail was manufactured, drilled, painted and on site within four weeks of the order, and then bolted into position under the roof trusses, at 18m, by the structural steelwork company erecting the building. After the building had been erected and clad, a team of CTI engineers levelled and aligned the rails to a tolerance of ±2mm.
The manual crane was then delivered and erected on the floor, and lifted into position using three mobile cranes. Twelve weeks after the installation of the manual crane, the first of the automatic cranes was installed, with the last one being installed four weeks later.
The fully automatic cranes were fitted with a laser positioning system designed by CTI Systems, which not only positions them on the long travel axis, but also enables the cranes to slew along their lengths, and position to within ±5mm over the tanks. The two automatic cranes are fitted with specially designed automatic grapples that grip and support the aluminium flight bars along both sides of their full length.
The flight bars supplied by CTI Systems were designed to handle the ‘Arrowhead’ hangers supplied by BAe for suspending the aluminium Airbus wing skins from the integrated busbar during the process. In the actual anodising process, the flight bar is lowered into eight electrical contacts that deliver current of up to 18,000A to the work piece. Each flight bar was manufactured entirely from special extruded aluminium profile, with stainless steel fixings and weighs 2.5t.
The transfer car was designed to receive the aluminium Airbus wing skins from the production facility and automatically hand them over to one of the automatic cranes. The transfer car runs on three floor-mounted rails and is able to slew along its length to allow it to align with the manual load facility and the automatic crane.
