New Process Forms Compound Curves in Ti
News from GKN Aerospace
GKN Aerospace has developed a new process that creates complex curved structures in titanium. Headquartered in Redditch, United Kingdom, GKN has already successfully used the new process, called delta pressure forming, to manufacture the cone-shaped titanium exhaust system for the Boeing 747-800. According to a July press release, the company also plans to use the new method to create complex shapes required for extremely rugged items, such as engine inlet lips and inner barrels, thrust reverser inner fixed structures, and exhaust nozzles and plugs.
GKN begins the process by producing flat panels of titanium honeycomb sandwich. Before delta pressure forming, the panels were shaped using a drape forming technique. In this process, the flat panel was draped around a die in a vacuum furnace at temperatures above 1000°F. Static weights were attached to the ends of the panel to help it achieve a straight cylindrical or conical shape.
In the new delta pressure forming process, the honeycomb barrel is formed with an improved drape creep forming process that employs a roller system in place of static weights. The cylindrical barrel is then inflated into a die to create the required compound curvature. The operation is conducted in a vacuum furnace at temperatures exceeding 1500°F and the inflation pressure is provided by inert argon gas. Forming analyses and tooling features developed specifically for this process ensure that the honeycomb core and the face sheets are not damaged.
GKN is a global independent supplier of structures, components, assemblies and engineering services to aircraft and aero engine manufacturers.
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