Patent ID: 6886383
Filing Date: 2005-05-03
Classification: B21D

Abstract:
1. A method of forming a sheet metal article from a blank of sheet metal that has been heated for stretch forming, said method being performed using a set of opposing tools, said tools comprising a punch having a punch surface defining a predetermined finish configuration for said article and a cavity tool having a cavity surface defining a preform configuration for said article, said method comprising: placing a said blank between said opposing tools, said blank having a first side surface facing said cavity tool and a second side surface facing said punch; pressing said punch against the second side surface of said sheet to push the first side surface of said sheet against said cavity tool surface to stretch and shape said blank in a sheet metal preform configuration that does not conform fully to either said cavity surface or said punch surface; and applying gas pressure to said first side surface of said blank to press said second side surface against said punch surface, but not against said cavity surface, to shape said blank from said sheet metal preform configuration to said finish configuration.