Apparatus and method for retention of thin foils during forming

摘要

A pair of forming elements incorporate features which restrain a thin foil workpiece without requiring high or excessive clamping pressures. A retaining step is provided in the second forming element having the forming cavity. It has been found that thin foil workpieces bent over and engaged by contact with the retaining step are secured against slippage with reduced clamping pressures. Moreover, the thin foil workpieces exhibit material draw during forming without the excessive lateral pressure between clamping surfaces that causes wrinkles. Substantially wrinkle-free flanges remain in the formed article.