ONCE assembly fixture (FITR)
The ONCE assembly fixture (FITR) is a purpose built fixture designed to hold the Boeing F/A-18E/F Super Hornet TEF assembly during the automated drilling cycle. Designed around a basic picture frame type jig, the FITR incorporates a rotisserie mechanism to allow fastening operations on both the upper and lower surfaces of the flap without removal of the component from the fixture. Indexpiers on either end of the picture frame are assembled with roller bearings to support the picture frame rotisserie axles as well as provide the features for the rotational indexes. Besides a basic 0 and 180 deg index position, there is also an additional position at 135deg to provide the robot optimum access to the high curvature areas of the upper skin leading edge. A manually operated worm drive gearbox facilitates movement between these rotary index positions. At each of the three rotisserie index angles there is a separate datum target that the MFEE resynchronization camera aligns to before beginning the drilling cycle on that side.
Additionally, the FITR has been designed for the possibility of integrating other aircraft components in the future. In order to expedite the conversion to a different component, the picture frame is removable from the cell. A simple handling and transportation cart has been designed to maneuver the picture frame in and out of the rotisserie pivots. Since future picture frames may be longer than the current TEF frame, one of the piers is mounted on a linear bearing slide plate so that the axial distance between the rotisserie bearings can be increased to accommodate a larger component frame while still maintaining the pivot alignment.