Internal articulated mandrel for the stretch forming of elongated hollow metal sections

摘要

Disclosed is apparatus and a method for the stretch forming of an elongated hollow metal section, such as an aluminum extrusion. The apparatus and method of this invention uses a collapsible and expandable articulated mandrel positioned inside portions of the elongated hollow metal section to constrain and support the internal wall surfaces of the elongated hollow metal section against the reshaping forces imposed on the interior of the hollow metal section during the stretch forming operation. The mandrel disclosed herein prevents the formation of wrinkles and crimps being formed in the walls of the elongated hollow metal section during the stretch forming and reshaping thereof.