Gm Global Technolgoy Operations, Inc.

Leonard L Pollum

Paul Edward Krajewski

James Gregory Schroth

Richard Harry Hammar

Gary A Kruger

Edward W Bennett

Susan Elizabeth Hartfield-Wunsch

Work hardened sheets of formable metal are annealed by thermal conduction and heated to a forming temperature. In a preferred embodiment, the sheet is placed on a flat surface of a heated lower platen to partially heat and soften the sheet and an opposing heated upper platen is brought close enough to the sheet to contribute heat but not to constrain the sheet as it expands. The platens are then both brought close to the sheet to heat it to its forming temperature largely by thermal conduction.

Conduction preheating for hot-formed sheet metal panels

The distortion-free removal of a heat softened sheet metal part from a heated forming surface is enabled by the elevation of lift pads in the forming surface. Strategically located and sized pads are recessed in the forming surface of the hot forming tool and the pads are part of the forming surface. At the completion of the stretch forming, or other hot forming, of a sheet metal blank on the forming surface, the pads are lifted in unison, without rotating them, on lift posts by a suitable lift mechanism to carefully and uniformly strip the flexible part from the hot forming surface.

Extraction system for hot formed parts

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Lapeer, MI, United States of America

Leonard L Pollum