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US 3,943,741 AGranted
Embossing method
AssigneeThe United States of America as represented by the Secretary of the Army
InventorWillis W. Sunderland
Life of this patent
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Abstract
A cup-shaped blank is extruded through a die onto a cylindrical non-collable mandrel having an external surface pattern counter to a desired internal embossment. Subsequently, the embossed portion of the blank is hydrostatically expanded away from the mandrel to permit removal of the embossed part from the mandrel. The application of hydrostatic pressure to the exterior of the blank during the extruding operation is disclosed.
Claims8
A method of forming a hollow metal part having a desired internal embossment, comprises the steps of:
- extruding a hollow blank through a die onto a non-collapsible cylindrical mandrel having an external surface pattern counter to the desired embossment in said part, to emboss a portion of the blank;
- and
- hydrostatically expanding the embossed portion of said blank outward away from said mandrel, to release the blank from the mandrel for removal therefrom.
Dependencies are inferred from the claim text.