DEVELOPMENT OF A RECONFIGURABLE TOOL FOR FORMING AIRCRAFT BODY PANELS

To significantly cut the time and cost of tooling development, a recon figurable discrete die (that is, matrix of individually actuated pins) is being developed for aircraft fuselage parts made by forming sheet metal or molding of composite materials. Each pin in the die is a simp le hydraulic actuator outfitted with an in-line NC solenoid valve to c ontrol its vertical position. Pin positions can either be set in a clo sed or open-loop fashion. Once the pins are ''set,'' then the entire m atrix is clamped into a rigid tool. A single pin was constructed to re solve several design issues, including the removal of trapped air in t he hydraulic circuit, prevention of hydraulic leakage, motion control, and quantifying the dynamic frictional forces. Because the performanc e of the single pin was deemed acceptable, a 4 x 4 test die of similar design has been constructed to establish the frictional interactions between adjacent pins, the workability of the pin matrix clamping sche me, and the feasibility of closed and open-loop control of pin positio ning.