Automated Installation of an Expanded Light-Weight Rivetless Nut Plate Assembly

Installation of removable access panels and sub-assemblies frequently requires installation of anchor nut plates in the support structure. Several nut plate methods are used including conventional riveted nut plates, gang channels, or bonded or glued-on nut plates. None of these current methods lend themselves to automated assembly. Fatigue Technology Inc. (FTI) has designed and adapted its ForceTec® rivetless nut plate into an innovative light weight aluminum ForceTec “Lite” product that is fully assembled with a self locking nut element encapsulated in a sealed dome or shell. This paper will present a new method of installing an expanded rivetless nut plate using a unique segmented mandrel that expands the completely assembled nut plate into a pre-drilled hole. The paper will describe qualification testing of the product and suggested automated assembly sequences and concepts that could be adapted to a number of structural locations using automated structural assembly jigs or fixtures. Installation rates of better than one nut plate every five seconds have been achieved by hand. It is conceivable that this rate could be improved upon through automation.