Interface Management in Wing-Box Assembly 2011-01-2640

Gaps between structural components have been a common problem since the start of aviation. This has usually been caused by the manufacturing tolerances of the components in question not being sufficiently tight. An example where such issues arise is in the assembly of a wing skin to rib feet to form an aircraft wing-box, where it is commonly found that, whilst some rib feet are in contact with the wing skin, others are spaced from it. Yet a strong connection between the wing skin and the rib feet is important to maintain the structural strength of the wing-box. To eliminate the existing gaps, the current approach, used in many manufacturing production lines, involves filling in the gaps to the required shape by applying liquid or solid shim to the rib feet. This is a relatively long and expensive process.

To overcome these current inherent difficulties in interface management, a method to eliminate the shimming requirement between component interfaces is presented. It is achieved by developing automated methods and processes that remove a known excess of material from the appropriate interfaces using sophisticated rapid metrology techniques and advanced equipments such as gantry mounted robots, NC machines, or local rapid-machining centres. The paper considers various solutions for a shim-less assembly approach originating from: design for manufacturing, the application of metrology systems, jigs and fixturing design, automation processes, and technology development.