Hand installation of 3/8", 5/16" and 1/4" diameter fatigue head style fasteners is required on some areas of 747 section 11 (center wing). The 3/8" diameter fasteners can require between 45-60 seconds to upset using conventional pneumatic riveting guns. As part of Boeing’s continuing effort to reduce cycle time and improve the factory working environment, a Boeing Quality Circle Team proposed using LVER technology as an alternative to conventional pneumatic percussion riveting hammers The hand operated HH500 system was developed in response to this request. The HH500 single shot upset reduces installation time as well as the noise levels and vibration experienced by the operators. The design of this system and the integration onto the factory floor are presented.
The LVER forming rate is significantly higher than that of conventional pneumatic and hydraulic processes. Verification that this type of fastener formation maintains the integrity of the fastened joint is therefore required prior to introduction of this process into the production environment. Each new application typically requires modification of the riveting die geometry and/or determination of the system parameters to meet the BAC specifications. Preliminary fatigue studies indicated that the HH500 installed fasteners exhibited fatigue lives comparable to conventionally installed fasteners. Statistical design of experiment, D.O.E., studies were then used to further optimize the system parameters. Results from these studies are presented.
To date the HH500 system has been qualified to install approximately 1000 fasteners on the 747 Section 11 and has been in production since March 1992. Work continues on extending the amount of qualified fasteners and on elimination of the coldworking process currently required for all hand installed fasteners on these panels. An update on this work and on experience of using the HH500 in production are discussed.