Patent ID: 6199419
Filing Date: 2001-03-13
Classification: B21D

Abstract:
A method of forming a dome from a substantially round blank wherein a surface area requirement of said dome is greater than a surface area of said blank, said method comprising the steps of:shear forming said blank, said shear forming step comprising the steps of;coaxially securing an inside surface of the blank to a rotatable flat-nosed conical mandrel;rotating said blank on said flat-nosed conical mandrel;heating a predetermined portion of said blank; andapplying a force to an outer surface of said blank such that said blank is shear formed in a shape of said flat-nosed conical mandrel to form a deformed blank;additional shear forming said deformed blank in predetermined locations such that a thickness of said blank in said predetermined locations is reduced to form a stretched blank;removing said stretched blank from said mandrel;inside spinning said stretched blank to form a dome shaped blank, said inside spinning step comprising the steps of;coaxially securing an outside surface of said stretched blank within a rotatable concave dome mandrel;rotating said stretched blank on said concave dome mandrel;heating a predetermined portion of said stretched blank; andapplying a force to an inner surface of said stretched blank such that said stretched blank is deformed to form said dome shaped blank;removing said dome shaped blank from said concave dome mandrel;final dome spinning said dome shaped blank into said dome, said final dome spinning step comprising the steps of;coaxially securing an inside surface of said dome shaped blank to a rotatable convex dome mandrel;rotating said dome shaped blank on said convex dome mandrel;heating a predetermined portion of said dome shaped blank; andapplying a force to said outside surface of said dome shaped blank such that said dome shaped blank is deformed in a shape of said convex dome mandrel to form said dome; andflange spinning said dome, said flange spinning step comprising the steps of:rotating said dome shaped blank on said convex dome mandrel;heating a flange portion of said dome shaped blank; andapplying a force to a surface of said range portion such that said flange portion is deformed such that a thickness of said flange is increased and such that a length of said flange is decreased.