Patent ID: 7834292
Filing Date: 2010-11-16
Classification: B23K,Y10T

Abstract:
1. A method for making an electric resistance weld between a workpiece and a laminated metal sheet having an outer metal sheet and an inner metal sheet bonded together by a polymer material, in which the workpiece has been previously welded to the laminated metal sheet so that inner metal sheet is already positioned against and attached to the workpiece and therefore not accessible to tooling comprising: applying a punch against the outer metal sheet and driving the punch through the laminated metal sheet and against the workpiece so that a hole is created by the progressive forced insertion of the punch through the outer metal sheet, the polymer material and the inner sheet of the laminated metal sheet, said forced insertion of the punch causing displacement of material from the outer metal sheet to form a first annular metallic burr that bridges across the polymer material layer between the outer metal sheet and the inner metal sheet thus providing a path for electrical current flow between the outer metal sheet and the inner metal sheet that would otherwise be insulated from each other by the polymer material layer; and positioning a weld electrode against the outer metal sheet at the punched hole and applying weld current that is conducted directly to the outer metal sheet and then through the first annular metallic burr to inner metal sheet to create an electric resistance weld between the laminated metal and the workpiece.