The art of wing assembly
Airbus Industries investigates new technologies and techniques for improving quality and reducing cost of its wing box assemblies.
by Stuart Birch, European Editor
Most aerospace engineers would agree that building aircraft is not like building high-volume cars. Markets, materials, monetary investment, and manufacturing processes and requirements are all very different. The automated assembly procedures embraced with enthusiasm by the automotive industry in the 1970s and 1980s were not seen as generally necessary in the world of aircraft production. However, philosophies often change with practical experience. In the auto industry during the last few years, there has been some significant re-thinking regarding the application of automation, resulting in a more subtle understanding of its strengths in particular applications. It is useful for repetitive high-precision needs and for easing physically awkward tasks. Meanwhile, in the mainly labor-intensive aerospace industry, automated manufacture has gained credibility in some areas as production volumes have risen and some market prospects look more positive.
 The AWBA II cell integrates handling, positioning, measuring, robotic drilling, wing skin panel wrapping, and fastening technologies in a single 8.5-m high demonstrator. |
Airbus (BAE Systems owns 20% of Airbus and EADS 80%) has a manufacturing schedule that projects production of more than 38 wing sets a month by 2005—at least 12 greater than its current average. Therefore, the company has unveiled details of the second phase of its new automated wing box assembly (AWBA II) research project, which, if implemented, it says could greatly reduce costs and lead times of the wing assembly process. The AWBA II project is just one example of leading-edge manufacturing technologies being examined by Airbus to help meet delivery schedules as orders grow and also to facilitate manufacture of more sophisticated wing designs. For example, the A380 will have more than twice the wingspan of the A318 and be 25% bigger than that of the A340-500/600 wing, which is the largest Airbus wing produced to date.
AWBA II integrates handling, positioning, measuring, robotic drilling, wing skin panel wrapping, and fastening technologies in a single 8.5-m high demonstrator. Having proved the concept of wing skin panel wrapping, the demonstrator cell is also capable of handling and positioning a 6-m high wing rib "quickly and safely." Further operations in the AWBA II cell demonstrator will entail evaluations for cost, accuracy, and repeatability compared to manual assembly methods, plus scale-up implications and any aerodynamic and systems effects.
 The layout of the AWBA II cell demonstrator. Click to enlarge |
AWBA II is a partnership of seven UK-based companies, each responsible for designing, manufacturing, and evaluating different elements within the cell demonstrator. Airbus' business unit in the UK has responsibility for project management and provision of facilities and materials. The other companies are AEA Technology (robotic fastening process control); AMTRI (automated handling and positioning systems); BAE Systems Advanced Technology Centre (ATC) in Sowerby (vision and sensor automated positioning systems); Leica (measuring systems); Tecnomatix (software and simulation packages); and RTS Advanced Robotics (robotic technologies).
AWBA II is building on the achievements of AWBA I, which led to the approval of the original concept for automated assembly and the development of four individual demonstrators to better understand robot positioning, skin panel-to-rib feet robotic drilling, skin panel positioning and wrapping, and process control. AWBA I began in 1995 with the aim of identifying specific elements of technology for automated assembly of large wings. AWBA II is a two-year project funded in part by the UK's Department of Trade and Industry with four specific aims: to demonstrate flexible manufacturing within a single manufacturing cell; to examine how low-cost technologies can be best applied and used; to acquire specific enabling technologies; and to identify further technology gaps.
Key achievements of the project so far include: a demonstration of a potential step-change in wing assembly processes; a demonstration of the ability to load and support a large rib quickly and safely; validation of the skin-wrapping concept; and ensuring robots are capable of working in unison within the demonstrator. There are a range of issues to consider next, including costs against equivalent labor costs, accuracy and repeatability, development of fasteners, aerodynamic tolerances and systems integration, and scale-up and additional/unique assembly requirements. At present, the cell demonstrator is working with A380-size ribs as test pieces.
