Womb to Tomb SPC Control of Fasteners from Rivet Manufacture to Installation using Existing Software 2003-01-2958
Controlling rivet tolerances, and the hole tolerances that these rivets are inserted into, are some of the most important requirements in the manufacture of aircraft. Because of the laminar air flow over the outside of the skin in all aircraft, and the stealth requirements of military aircraft, the rivets must sit flush with the Outside Mode Line of the exterior skin. This countersink depth must be tightly controlled in tolerance, both in the hole diameter & countersink, and also in the manufacture of the rivets. In the past, the aircraft OEM's have driven, independently, the rivet manufacturer and the machine manufacturer drilling the holes, to control tighter and tighter tolerances. The conventional way to get better performance is to implement SPC independently into the rivet manufacturing process and also into the machine hole drilling process. Let's consider first the rivet manufacturing process. Chart A shows a typical dispersion in a manufacturing “lot” of rivets by the rivet manufacturer.