Method of drawing a blank by preforming a channel in a preform that is subsequently drawn into a die cavity

Abstract

A method of forming a blank into a part shape is provided in which the blank is drawn into one or more channels sequentially to form at least one pocket of material that is available to be drawn into the die cavity. Each pocket is formed by applying liquid pressure or mechanical pressure to form the blank into the channels. The channels may be filled with a liquid to reduce friction. Alternatively, portions of the blank may be drawn into a channel to form a first stage preform that includes a pocket. The pocket of the first stage preform is then drawn into the die cavity in a first partial drawing stage. The steps of drawing material into the channel and then into the die cavity may be repeated one or more times until the part is fully drawn into the desired shape.

Dependencies are inferred from the claim text.