Aluminium profiles support efficient wing manufacture

Described as 'the future of air travel', the Airbus A350 XWB (extra-wide body) has been welcomed by airlines, with 548 aircraft having been ordered before the first had left the factory. Wings for the new aircraft are manufactured at the Airbus facility at Broughton near Chester in the UK. Electroimpact, one of the world's leading designers of tooling and automation for the aerospace sector, was contracted to design and construct the manufacturing system.

Electroimpact has worked on a number of Airbus projects previously and has been responsible for providing the wing manufacturing systems for the A320, A330, A340 and the A400M military transport aircraft. A more recent high-profile project was the Airbus A380, which is the world's largest commercial passenger aircraft to date.

However, it is not only the design of the Airbus 350 XWB that is state-of-the-art; the manufacturing process for the wings has also been revolutionised. Damon Griffiths, the project support manager at Electroimpact, states: "Airbus has had a complete change in philosophy about wing manufacture on the A350 XWB, going from a vertical build, with the leading edge pointing to the roof during assembly, to a horizontal build - the first time this has ever been attempted by Airbus.

"A key advantage of horizontal wing manufacture is the use of a pulse system during the wing build, which is a first within the aerospace business."

AGVs and assembly jigs

With the new process, the horizontal wing, which measures 33m in length, is moved between the different workstations, without the orientation of the wing changing during the course of the build.

Automated guided vehicles (AGVs) transport the wing as opposed to the traditional overhead cranes used for vertical manufacture. With the new process, a wing assembly jig holds the wing in place while the top and lower covers are placed around the skeleton with a series of drilling and fixing operations.

Modern wing manufacture is highly automated in order to speed up the manufacturing process, with many of the rib-to-spar assembly operations being performed by machines that are integrated with manual operations where necessary.

However, the Airbus decision to adopt horizontal manufacture was not without its issues, as Griffiths explains: "Horizontal manufacture involves having the wings high enough off the ground for the machines to pass under; in particular, the lower drilling, bolting and lower tacking machine. Secondly, it creates means-of-access issues for the operators who require under-cover (ie under the wing skin) and under-structure access."

Novel access platforms

With this in mind, project managers for Electroimpact realised that a new design of access platforms would be required to work on the wings and turned to Bosch Rexroth for help.

Griffiths continues: "We had certain key criteria for the new access platforms to help us overcome the issues with horizontal manufacture. Firstly, the access platform heights would be driven by the build network throughout the length of the wing.

"Secondly, ergonomics were a key design aspect of the platforms, which meant we needed to take into account the curvature of the wing to ensure access at the correct height position and, in turn, minimise strain on the human body.

"Thirdly, we needed to integrate the point-of-use principles for manufacture, as it was essential we had as many facilities as possible - such as pneumatics, air and electric points - close to the operation.

"Finally, we wanted maximum flexibility in terms of movement of the lower access platforms, with a solution that was versatile enough to be deployed by two men in the required tack times and robust enough to withstand some harsh treatment."

Bespoke platforms

Bosch Rexroth helped Electroimpact to create a total of four bespoke inboard platforms and 36 bespoke lower access platforms, all made from aluminium profiles and accessories. The platforms would be utilised within the manufacturing cells during production to form a complete platform throughout the length and width of the wing.

The inboard platforms, measuring approximately 14m long and 6m wide, are manoeuvred into place at the widest part of the wing using a large AGV beneath the chassis of the platform. In addition, the 36 lower access platforms use hinged flip flooring as part of their features. When the platforms are being used in production they then link together to create one single platform.

Both the inboard and lower access platforms have features such as drop-down guarding, point-of-use services and lighting in the floor. Bosch Rexroth also provided access steps, handrails for fencing between production cells and flag carts for the storage of components.

Griffiths says: "In all, the Rexroth platforms cost more than 0.75million, offering enormous advantages compared to a heavy, fixed, welded structure. The platforms offer a more cost-effective solution overall, with its modular design and construction providing more flexibility during manufacture and for ongoing modifications onsite, importantly without taking away the platforms from the customers.

"We have delivered a solution to access all areas of the wing with minimal additional equipment and given Airbus the chance to construct the new wing in a safe manner."

Follow the link for more information about Rexroth's aluminium profile framework construction system.