Method and apparatus for sequential axial feed hydroforming

摘要

A tube member is placed in a die having a plurality of nodules formed in the cavity thereof. A chamber is formed between a mandrel and end piece within the tube. The mandrel is positioned adjacent a first of the nodules and the chamber is pressurized during a hydroforming cycle to form a node on the tube by simultaneously expanding a portion of the tube outward and feeding the tube linearly into the die cavity. A mechanism for feeding the tube linearly is external to the die cavity and has a member in abutment with one end of the tube. During a positioning cycle, the pressure in the chamber is reduced and the mandrel is moved longitudinally within the tube to a position adjacent the next sequential nodule to permit a repeat of the hydroforming cycle. In one embodiment of the hydroforming process, a mandrel is positioned into the tube from each tube end and a feed mechanism is disposed adjacent each tube end. This permits the sequential simultaneous hydroforming of pairs of nodes on the tube.