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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.

Increased attention is being paid to the quality, consistency and cost of aircraft panel fastening operations. The advent of automated fastening has made it possible to achieve substantially greater productivity and quality, however it has also made more evident than ever that inadvertently mixed or otherwise deficient fasteners exact a cost and quality toll that can no longer be accepted. AHG has developed a fastener on line storage, delivery and inspection system that can substantially alleviate these problems. The AHG Modular Cassette Fastener and Delivery System and its associated Inspection and Reloading System permit the end user to inspect, sort, orient, refill and code the Modular Cassettes in a single operation. The inspection process is performed automatically by a combination of sensors, video cameras and software, all of which are under the control of a PC.

A cassette based fastener feeding system has been developped to support the evolving quality requirements of automated rivet installation machines. The fasteners are properly oriented and contained within a tube enclosed within the cassette. The system provides a substantial increase in installed fastener quality, reduces machine down time, and makes autonomation practical.

The development of improved fastening systems has made a substantial contribution to the consistency and repeatability of the rivet installation process in the Aerospace Industry. In order to take maximum advantage of the fatigue life improvement that this repeatability makes possible, the industry has expended substantial effort in identifying those parameters that govern the hole fill that can be achieved. A rivet has been designed which expands in a more predictable and controllable fashion than rivets currently in use, and which therefore is more “forgiving to the hole”. This new rivet's superior ability to adapt, in combination with automated systems capability to limit the deviation in hole size, has provided the industry with the means of achieving substantially higher fatigue life. The rivet, originally developed by Lockheed, is called the Aerolock and its introduction has made a substantial contribution to the enhancement of manually and automatically installed rivets.