HansonSmith, R. and Merkley, A., "Flex Track One Sided One Up Assembly," SAE Int. J. Aerosp. 7(2):328-331, 2014, doi:10.4271/2014-01-2274.
The Boeing Company is striving to improve quality and reduce defects and injuries through the implementation of lightweight “Right Sized” automated drill and fasten equipment. This has lead to the factory adopting Boeing developed and supplier built flex track drill and countersink machines for drilling fuselage circumferential joins, wing panel to spar and wing splice stringers. The natural evolution of this technology is the addition of fastener installation to enable One Up Assembly. The critical component of One Up Assembly is keeping the joint squeezed tightly together to prevent burrs and debris at the interface. Traditionally this is done by two-sided machines providing concentric clamp up around the hole while it is being drilled. It was proposed that for stiff structure, the joint could be held together by beginning adjacent to a tack fastener, and assemble the joint sequentially using the adjacent hole clamp up from the previous hole to keep the joint clamped up. This process would significantly decrease the costs and complexity that is usually associated with two sided equipment involved in One Up drilling and fastening. This paper will examine the equipment and testing completed to prove out the process of using adjacent hole clamp up to achieve One Up Assembly.