Method and Tool for Expanding Tubular Members by Electro-Hydraulic Forming

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.

1 - 17 . (canceled) 
     
     
         18 . A tool for forming a tubular part comprising:
 a tubular member;   an electro hydraulic forming (EHF) die into which the tubular member is inserted;   an electrode assembly having an electrode wire having a positive lead and a negative lead, the electrode wire is disposed within a cartridge that is filled with a first volume of fluid, the assembly is inserted within the tubular member, a second volume of fluid is provided within the tubular member and the dual electrode assembly is submerged in the second volume of fluid;   an energy storage device; and   a controller that discharges the energy storage device to provide an electrical discharge to the positive lead and the negative lead of the electrode wire in the electrode assembly that provides a shock wave that passes through the fluid to conform the tubular member with the electro hydraulic forming die.   
     
     
         19 . The tool of  claim 18  wherein the electrode wire is helically coiled and extends in two segments that extend substantially the full length of the cartridge, the two segments are connected one to each of the leads. 
     
     
         20 . The tool of  claim 19  further comprising an insulator that is disposed between the two segments of the wire except at a distal end of the wire where the two segments are reversely turned relative to each other. 
     
     
         21 . The tool of  claim 18  wherein the cartridge is a plastic tube that is destroyed when the electrical discharge is provided. 
     
     
         22 . (canceled)