Importance

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Abstract

A method and apparatus for hydro-forming desired features into the walls of thin-walled objects such as small tubes. A mold is provided having an internal surface that is sized and shaped to support the wall of the tubing or other workpiece and defines cavities that correspond to the desired features. A fluid filled hollow needle having no O-rings or seals thereon is provided that has at least one opening therein for supplying hydraulic fluid under pressure to the inside surface of the tubing. The needle has an outer diameter that is smaller than the inner diameter of the tubing to form a small clearance therebetween when the needle is in the tubing. The clearance is sized to prevent any substantial leakage of fluid from the needle and provide a pressure drop in the clearance sufficient to maintain the pressure of the fluid, at the portions of the wall to be deformed, high enough to deform the wall, while also facilitating insertion and removal of the needle into and from the tubing. The needle is inserted into the tubing and a pulse of hydraulic pressure is applied to the fluid inside the needle for transmission through the opening(s) in the needle to the inner surface of the tubing to deform the wall of the tubing into the cavities in the mold to form the features on the tubing.

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First Claim