Hydraulic pressure forming using a self aligning and activating die system

A hydroforming method in a system comprising a a die set having a mounted lower die half, and an adjacent movable upper die half, the die halves in closed position having an interior surface that defines a shape of a die cavity for receiving a workpiece, the upper die half having a first set of reinforcement plates attached along an exterior surface of the upper die half, the lower die half having a second set of reinforcement plates attached along an exterior surface of the lower die half;

• a means to seal ends of a workpiece;
• a means to increase internal fluid pressure of the workpiece to a predetermined level;
• a plurality of activation hydraulic cylinders mounted to the die halves comprising a first clamping chamber, a first extension chamber, a first cylinder rod having a first cylinder rod end, and a first piston, the first clamping chamber mounted to the lower die half, and the first cylinder rod end mounted to the upper die half;
• a plurality of clamping hydraulic cylinders mounted to the die halves comprising, a second clamping chamber, a second extension chamber, a second cylinder rod having a second cylinder rod end, and a second piston, the second clamping chamber mounted to the lower die half, and the second cylinder rod end releasably mounted to the upper die half with a slide couplers/clevis unit;
• a means to pump hydraulic fluid into and out of the clamping and extension chambers of the plurality of activation and clamping hydraulic cylinders;
• and
• a computer control system, the method comprising the steps of:
• raising the upper die half;
• placing a length of tube, representing the workpiece, between the mounted lower die half and the raised upper die half;
• pumping fluid out of the extension chambers and into the clamping chambers of the activation hydraulic cylinders causing the upper die half to move to meet the lower die half;
• engaging the clamping hydraulic cylinders when the upper die half reaches a pause position;
• assisting the activation hydraulic cylinders by engaging the second cylinder rod ends and the slide couplers/clevis units;
• thrusting end plugs onto ends of the workpiece using drive cylinders;
• providing, by fluid pressure, an outward force against the walls of the workpiece to expand and conform to the shape defined by the die cavity surface;
• stopping fluid flow into the workpiece when the forming load reaches a predetermined maximum;
• relieving the internal pressure;
• removing the end plugs from the ends of the workpiece by reversing the drive cylinders;
• evacuating the fluid from the clamping chambers of the plurality of activation hydraulic cylinders and clamping hydraulic cylinders while simultaneously pumping fluid into the extension chambers of the activation hydraulic cylinders and clamping hydraulic cylinders, causing the upper die half to separate from the lower die half to a pause position;
• disengaging the rod end slide couplers/clevis units;
• and
• causing the upper die half to further separate from the lower die half to a position that allows removal of the formed workpiece.