Inventors:
Emmanuil Shrayer - Lexington MA
Richard J. Morganti - Billerica MA
International Classification:
B21H 100
Abstract:
Disclosed is a method of forming a dome from a substantially round blank having a surface area smaller than the surface area of the dome. The basic embodiment of the method includes the steps of shear forming the blank to form a deformed blank, spin stretching the deformed blank in selected areas along its circumference to form a stretched blank, inside spinning the stretched blank into a rough dome, and finish spinning the rough dome into the finished dome. In the preferred embodiment, the shear forming step involves coaxially securing an inside surface of the blank to a rotatable flat-nosed conical mandrel, rotating the blank on the flat-nosed conical mandrel, heating a predetermined portion of the blank, and applying a force to an outer surface of the blank such that the blank is deformed in a shape of the flat-nosed conical mandrel to shear form the deformed blank. In this embodiment, the additional spin-stretching step involves spin-stretching the deformed blank in predetermined locations to form a stretched blank having a surface area that is substantially greater than the surface area of the dome. The preferred inside spinning step involves securing the stretched blank within a rotatable concave dome mandrel, rotating the blank on the concave dome mandrel, heating a predetermined portion of the stretched blank, and applying a force to the inner surface of the stretched blank to form a dome shaped blank.