Europe's largest autoclave for A380 wing manufacture
Europe's largest autoclave for A380 wing manufacture
Keywords: Aircraft,Wings,Manufacture
Occasionally, the notion that hi-tech means equipment getting ever smaller is blown out of the water. One such example was quite visible on the roads of Britain recently with the transportation of a 300 ton autoclave from Lincoln to North Wales. Hidden behind the colossal exterior of this machinery lies some highly Innovative engineering by UK firm Aeroform Ltd.
The technology employed by Aeroform was key to winning a £5 million contract from Airbus in the face of rival bids from two larger manufacturers. The 40m long autoclave will be used in the "creep forming" process to manufacture the aluminium wing skin panels for the A380 super-jumbo, at Airbus's factory in Broughton, Flintshire, UK.
Creep forming is used to shape the wingskins and strengthen them. The flat wing skin is formed over the surface of a shaped tool. It is then placed inside an autoclave and subjected to a heat treatment cycle. The process induces a combination of complex stress relaxation which results in the wing's curved shape.
The challenge was to design an autoclave capable of processing a high mass component over 30m in length and of varying shape and thickness. Once it was clear that the traditional method of axial heat flow would not be effective in this creep forming process, Aeroform came up with a circumferential airflow system modeled using fluid dynamics and finite element analysis.
The system, known as the Circumferential Airflow Technology System (CATS), is designed to achieve hot air impingement directly onto the wing skin surface in a series of individually controlled zones.
Each wing skin is to be processed under heat and pressure for a period of up to 18h during which time the temperature fluctuation in the component will be maintained at ±2°C or better. The system incorporates Aeroform's patented gas fired radiant tube technology and achieves optimum heat transfer with the aid of nine separately controlled fans. The heat input and fan power for each zone can be varied individually and each zone has its own water-cooled heat rejection capability. The result is a totally software programmable,individually zoned, temperature controlled environment allowing the heat input to the component to be accurately profiled along the entire length of the wing skin.
Believed to be the largest of its kind to be built in Europe, the autoclave was commissioned in August last year and is used in the manufacturing process from last autumn. The A380 is expected to enter commercial service in 2006.
Months of planning were required to ensure that the autoclave was delivered on time to Airbus. Fabrication was carried out at a site in Uincoin and the autoclave was then shipped in three sections from Immingham around the top of Scotland to Ellesmere Port.
The final road journey, on Sunday 26th May, saw the machine transported on three trailers requiring special low axles. The 500 foot long convoy took a total of 16h to travel just 28 miles to the Airbus site. Siting of the machine was then carried out with extreme precision using Megalift hydraulic equipment over a 1 week period.
Having won the contract on the back of superior expertise in process control and autoclave design, Aeroform's boss Ian Toll describes his company's success as "Important for British manufacturing firms. Aerospace is making a significant investment in this area."
Aeroform's hi-tech machines are designed to process some of the world's most advanced materials, notable customers including Formula One racing car manufacturers, the Ministry of Defence and British Aerospace's former Space and Communications Division during the Arianne rocket project. This is the first time they have designed and built a machine of this magnitude.
For further details contact: Aeroform Ltd. Tel: 01202 683496; Fax: +44 (0)1202 675957; E-mail: sales@aeroform.co.uk;Web site: www.aeroform.co.uk
