Method of forming a sheet metal article by superplastic or quick plastic forming

摘要

A method is disclosed for forming sheet metal articles, such as automotive body panels, having significant curvatures in front-to-back and side-to-side directions. Opposing, complementary, preforming and final shape forming tools (310,334) are used in a single press. A sheet of superplastically or quick plastically formable sheet metal alloy (302), heated to a forming temperature, is first stretched against the preform tool (310) using pressurized gas to form a preform that has experienced most of the metal stretching required for the final part shape. The preform is removed from the preform tool (310) and formed against the opposing tool (334) with pressurized gas to obtain the final sheet metal part shape.