Bulge forming machine

A forming device comprising:

• a fluid source providing a pressurized fluid;
• a strongback having a die cavity;
• a tubular workpiece having a hollow interior;
• a plurality of die components mated to form a forming die having an internal cavity, the die being at least partially disposed in the die cavity of the strongback, the internal cavity being configured to correspond to a predetermined tube profile, the forming die surrounding at least a portion of the tubular workpiece;
• and
• a mandrel assembly disposed at least partially within the hollow interior of the tubular workpiece in an area proximate the die, the mandrel assembly being in sealing engagement with the hollow interior of the tubular workpiece, the mandrel assembly having at least one feed aperture in fluid connection with the fluid source, the at least one feed aperture directing the pressurized fluid against the hollow interior of the tubular workpiece to cause the tubular workpiece to expand into the internal cavity, the mandrel assembly including a necked-down portion through which the at least one feed aperture extends, the necked-down portion permitting the pressurized fluid to accumulate between the mandrel assembly and the tubular workpiece.

A forming device comprising:

• a fluid source providing a pressurized fluid;
• a strongback having a die cavity;
• a tubular workpiece having a hollow interior;
• a plurality of die components mated to form a forming die having an internal cavity, the die being at least partially disposed in the die cavity of the strongback, the internal cavity being configured to correspond to a predetermined tube profile, the forming die surrounding at least a portion of the tubular workpiece;
• a mandrel assembly disposed at least partially within the hollow interior of the tubular workpiece in an area proximate the die, the mandrel assembly being in sealing engagement with the hollow interior of the tubular workpiece, the mandrel assembly having at least one feed aperture in fluid connection with the fluid source, the at least one feed aperture directing the pressurized fluid against the hollow interior of the tubular workpiece to cause the tubular workpiece to expand into the internal cavity;
• and
• a set of ways aligned to the die cavity of the strongback, the ways permitting the die to be slid axially into and out of the strongback.

A method for forming a tubular workpiece having a hollow interior, the method comprising the steps of:

• providing a lower die component having a die aperture;
• placing the tubular workpiece into the die aperture of the lower die component;
• providing an upper die component having a die aperture, the upper die component configured to mate with the lower die component such that the die apertures of the upper and lower die components form an internal cavity that is configured to correspond to a predetermined tube profile, the internal cavity having a forming portion;
• placing the upper die component onto the tubular workpiece and the lower die component;
• providing a mandrel assembly having a pair of spaced apart seals and at least one feed aperture;
• inserting the mandrel assembly into the tubular workpiece such that the mandrel assembly is proximate the internal cavity and the spaced apart seals sealingly engage the surface of the hollow interior;
• providing a strongback having a die cavity;
• inserting the upper and lower die components into the die cavity of the strongback such that the forming portion of the die cavity is entirely housed within the die cavity;
• supplying the mandrel assembly with a pressurized fluid, the pressurized fluid exiting the mandrel assembly from the at least one feed aperture and exerting a force against at least a portion of the hollow interior of the tubular workpiece to expand into the internal cavity.

A method for forming a tubular workpiece having a hollow interior, the method comprising the steps of:

• providing a lower die component having a die aperture;
• placing the tubular workpiece into the die aperture of the lower die component;
• providing an upper die component having a die aperture, the upper die component configured to mate with the lower die component such that the die apertures of the upper and lower die components form an internal cavity that is configured to correspond to a predetermined tube profile;
• placing the upper die component onto the tubular workpiece and the lower die component;
• providing a mandrel assembly having a pair of spaced apart seals and at least one feed aperture;
• inserting the mandrel assembly into the tubular workpiece such that the mandrel assembly is proximate the internal cavity and the spaced apart seals sealingly engage the surface of the hollow interior;
• providing a strongback having a die cavity;
• inserting the upper and lower die components into the die cavity of the strongback;
• supplying the mandrel assembly with a pressurized fluid, the pressurized fluid exiting the mandrel assembly from the at least one feed aperture and exerting a force against at least a portion of the hollow interior of the tubular workpiece to expand into the internal cavity;
• releasing the pressurized fluid and draining the mandrel assembly;
• removing the upper and lower die components from the die cavity of the strongback;
• removing the mandrel assembly from the tubular workpiece;
• and
• separating the upper and lower die components with a linear drive mechanism.