Patent ID: 9302312
Filing Date: 2016-04-05
CPC Classification: B21D

Claim Text:
1. A method of forming a sheet metal workpiece, mechanically formed using opposing, press-actuated, forming dies with opposing die forming surfaces that are closed against surfaces of the sheet metal workpiece to form it by the shape of the die forming surfaces, and the forming dies are then opened from the surfaces of the workpiece to enable removal of the formed workpiece from the forming dies and the press; the method comprising: preheating the sheet metal workpiece to a temperature in the range of about 100° C. to about 500° C.; applying a coating of a liquid lubricant material to only the forming surfaces of the forming dies, the forming dies being unheated above an ambient temperature, except as they may be heated by repeated forming of sheet metal workpieces, the liquid lubricant material being composed to lubricate the interface of the die forming surfaces and the surfaces of the sheet metal workpiece during forming of the workpiece and to later vaporize from the surfaces of the formed workpiece at a temperature below about 200° C.; inserting the preheated sheet metal workpiece between the liquid lubricant material-coated forming surfaces of the forming dies; closing the liquid lubricant material-coated forming surfaces of the forming dies against the surfaces of the preheated sheet metal workpiece to form the workpiece into the shapes of the die forming surfaces, some of the liquid lubricant material being transferred from the die forming surfaces to the heated sheet metal workpiece; opening the forming dies for removal of the formed workpiece from the dies and press while directing a stream of a carrier gas over the surfaces of the heated workpiece to remove the transferred liquid lubricant material from the heated workpiece as vapor; and removing the formed workpiece from the press.