Tomchick, S., Elrod, J., Eckstein, D., Sample, J. et al., "An Automated Production Fastening System for LGP and Hi-Lok Titanium Bolts for the Boeing 737 Wing Panel Assembly Line," SAE Technical Paper 2015-01-2514, 2015, doi:10.4271/2015-01-2514.
A new automated production system for installation of Lightweight Groove Proportioned (LGP) and Hi-Lock bolts in wing panels has been implemented in the Boeing 737 wing manufacturing facility in Renton, Washington. The system inserts LGP and Hi-Lok bolts into interference holes using a ball screw mechanical squeeze process supported by a back side rod-locked pneumatic clamp cylinder. Collars are fed and loaded onto a swage die retaining pin, and swaging is performed through ball screw mechanical squeeze. Offset and straight collar tools allow the machine to access 99.9% of fasteners in 3/16″, ¼″ and 5/16″ diameters. Collar stripping forces are resolved using a dynamic ram inertial technique that reduces the pull on the work piece. Titanium TN nuts are fed and loaded into a socket with a retaining spring, and installed on Hi-Loks Hi-Lok with a Bosch right angle nut runner. Bolt installation and collar swage heights and loads, as well as nut torque values are captured and logged for future reference.