Abstract: A method of testing metal samples is provided to simulate stretch flanging of trimmed surfaces. A sample having planar sides and a sidewall extending between the planar sides is placed in a fixture so that the planar sides are confined. The sidewall of the sample is bent about a curved surface while restricting buckling out of a planar area. One testing machine is disclosed in which a test specimen is clamped in a die with a nesting slot while a punch bends a sample against a forming surface that has a radius. In another testing machine, a mandrel and clamping element engage the planar sides of the sample while first and second bending members engage first and second end portions to bend one of the sidewalls of the sample about the mandrel.

Abstract: A method of forming a blank into a part shape is provided in which the blank is drawn into one or more channels sequentially to form at least one pocket of material that is available to be drawn into the die cavity. Each pocket is formed by applying liquid pressure or mechanical pressure to form the blank into the channels. The channels may be filled with a liquid to reduce friction. Alternatively, portions of the blank may be drawn into a channel to form a first stage preform that includes a pocket. The pocket of the first stage preform is then drawn into the die cavity in a first partial drawing stage. The steps of drawing material into the channel and then into the die cavity may be repeated one or more times until the part is fully drawn into the desired shape.

Abstract: A method and apparatus for forming flanges on a panel. The flanges may be weld flanges or hem flanges. The flanges stretch to reduce spring back and may be trimmed. The trimming operation is performed after the flange area is formed on the panel.

Abstract: A hydro-forming tool for use in a method of forming a blank into a liquid filled chamber. The chamber is formed by a container ring and a moveable wall that together define a variable volume chamber for containing the liquid. The wall is moveable relative to the container ring to provide a chamber in which the volume of liquid required to back up the blank is minimized. The liquid reduces friction at the chamber entry rim. Liquid may be ported through a counter punch to hydro-form the blank into the detail forming areas.

Abstract: An electrode assembly for electro-hydraulic forming tool in which the insulation sleeve is assembled over an electrode rod. The insulation sleeve has a deflection surface that is beveled or oriented at an angle relative to the axis of the electrode rod. The electrode assembly may include a replaceable conical receptacle that facilitates placement of an electrode tip an insulation sleeve tip. An electrode tip profile that is shaped to minimize erosion caused by discharge of the electro-hydraulic forming machine.

Abstract: A system for electro-hydraulically forming a sheet metal part in an electro-hydraulic forming (EHF) machine. The part in a first shape is placed in the EHF machine between a one-sided forming die and a chamber that is filled with a liquid. An electrode is discharged in the chamber to form the part toward the forming die. The electrode is advanced within the chamber toward the part and a subsequent discharge is provided in the chamber to form the part. A gap discharge EHF machine and a wire discharge EHF machine may be used in the system.

Abstract: An electro-hydraulic forming tool for forming a sheet metal blank in a one-sided die has first and second rigid rings that engage opposite sides of a sheet metal blank. The rigid rings are contained within slots on a die portion and a hydraulic force applicator portion of the forming tool. The seals are either resiliently biased by an elastomeric member or inherently resiliently biased into contact with the blank.

Abstract: A body panel assembly comprising an outer panel formed to a predetermined contour and a reinforcement assembly comprising a network or plurality of links that intersect to form a plurality of nodes. The network may be formed by a plurality of strips that are joined together at the nodes. The reinforcement assembly, or reinforcement panel, is attached with one surface flush to the outer body panel. One side of the reinforcement assembly is attached to the outer panel by brazing or bonding with an adhesive.

Abstract: A method of forming a part that has areas of high strain and predicted areas of low strain from a blank and method of designing a die for forming such a part. Predicted areas of low strain are identified that are adjacent to predicted areas of high strain. A pre-forming die is designed to form the blank to provide a donor pocket in an intermediate part in a predicted low strain area that is adjacent to the predicted high strain area. The donor pocket of the intermediate part is drawn into the predicted high strain area while forming the intermediate part into the part.

Abstract: A hydromechanical forming tool is disclosed that may include electro-hydraulic forming chambers in which a stored charge circuit may be discharged through electrodes to improve the level of detail that may be formed in a blank. The hydromechanical forming tool may include a liquid chamber at the entrance to the draw chamber to reduce friction, as the blank is drawn into the draw chamber. The draw chamber may have a movable bottom wall that is moved in tandem with the punch to reduce the amount of liquid in the draw chamber and reduce the need to pump liquid into and out of the draw chamber during a hydromechanical forming tool cycle.

Abstract: A method of using an electromagnetic forming machine to hem a panel assembly includes providing an inner panel and an outer panel. The outer panel has a plurality of flanges and a plurality of relief areas. An electric forming machine is provided having a coil for discharging electric energy to generate a magnetic field. The inner panel is positioned such that portions of the outer edge of the inner panel are aligned with the flanges of the outer panel to form a loose assembly of panels. The loose assembly of panels is positioned proximate the electromagnetic forming machine such that the coil surrounds the flanges and is disposed substantially coplanar with a plane formed by the relief areas. The electromagnetic forming machine is activated to generate a magnetic field causing the flanges to bend over.

Abstract: An electro-hydraulic forming tool having one or more electrodes for forming parts with sharp corners. The electrodes may be moved and sequentially discharged several times to form various areas of the tube. Alternatively, a plurality of electrodes may be provided that are provided within an insulating tube that defines a charge area opening. The insulating tube is moved to locate the charge area opening adjacent one of the electrodes to form spaced locations on a preform. In other embodiments, a filament wire is provided in a cartridge or supported by an insulative support.

Abstract: An electro-hydraulic forming tool for forming a sheet metal blank in a one-sided die has first and second rigid rings that engage opposite sides of a sheet metal blank. The rigid rings are contained within slots on a die portion and a hydraulic force applicator portion of the forming tool. The seals are either resiliently biased by an elastomeric member or inherently resiliently biased into contact with the blank.

Abstract: A tubular preform is contracted in an electro-hydraulic forming operation. The tubular preform is wrapped with one or more coils of wire and placed in a chamber of an electro-hydraulic forming tool. The electro-hydraulic forming tool is discharged to form a compressed area on a portion of the tube. The tube is then placed in a hydroforming tool that expands the tubular preform to form a part.

Abstract: A tubular preform is contracted in an electro-hydraulic forming operation. The tubular preform is wrapped with one or more coils of wire and placed in a chamber of an electro-hydraulic forming tool. The electro-hydraulic forming tool is discharged to form a compressed area on a portion of the tube. The tube is then placed in a hydroforming tool that expands the tubular preform to form a part.

Abstract: A tooling method for calibrating a partially formed metal part in an electro-hydraulic forming tool. The method includes loading a partially formed metal part onto a forming surface of a die. The part is then clamped onto the forming surface and the part is pulsed with a high rate energy pulse to overcome a spring-back effect in the part. The EHF calibration tool includes a punch to which a part is held by clamps while a capacitive discharge circuit is discharged through electrodes provided in the tool. Upon discharge of the capacitive discharge circuit through the electrodes, a high rate energy pulse is applied through a liquid to calibrate the part.

Abstract: A method of electrohydraulically trimming a blank involving positioning a blank on a trimming member having a cutting edge such that a portion to be trimmed extends over the cutting edge and is in fluid communication with a chamber. Immobilize the blank with respect to the trimming member. Position a pair of electrodes in the chamber proximate the portion of the blank to be trimmed such that the electrodes and the trimming member are on opposite sides of the blank. Electrically connect the electrodes to a capacitor. Charge the capacitor. Fill the chamber with fluid to submerge the electrodes and to contact the portion of the blank to be trimmed. Discharge the capacitor across the electrodes to generate a pressure pulse that pushes the portion of the blank to be trimmed against the cutting edge thus trimming it off the blank.

Abstract: An electrohydraulic forming (EHF) tool and a method of forming a sheet metal blank in an EHF operation. The tool may include a pair of electrodes and may be filled with a liquid. A high voltage discharge may be produced between the electrodes in a manner that induces a shockwave within the fluid. The shockwave may produce sufficient force within the liquid to form the blank against a die.

Abstract: A method of flange trimming a sheet metal panel to form a part including flanges for subsequent hemming or weld operation is disclosed. The method utilizes an electro-hydraulic forming (EHF) tool to form a channel within which a flange is cut out in a trimming operation. A combined flange/trim die may be provided in which both a channel forming operation and a flange trimming operation may be performed. A manufacturing system for fabricating a part by forming a channel in a peripheral portion and cutting the channel area to form a flange. The method also relates to a die for an EHF tool that defines a channel-shaped recess and has a trim edge for cutting a flange into the channel.

Abstract: A tooling method for calibrating a partially formed metal part in an electro-hydraulic forming tool. The method includes loading a partially formed metal part onto a forming surface of a die. The part is then clamped onto the forming surface and the part is pulsed with a high rate energy pulse to overcome a spring-back effect in the part. The EHF calibration tool includes a punch to which a part is held by clamps while a capacitive discharge circuit is discharged through electrodes provided in the tool. Upon discharge of the capacitive discharge circuit through the electrodes, a high rate energy pulse is applied through a liquid to calibrate the part.