Open AccessAnnual Report Electrochemical Machining of Access Holes
Author(s) -
J. F. Cooper,
M.C.W. Evans,
Richard E. Whipple
Publication year - 2006
Language(s) - English
Resource type - Reports
DOI - 10.2172/881665
Subject(s) - cathode , materials science , machining , electrolyte , drum , leakage (economics) , electrochemical machining , mechanical engineering , curvature , metallurgy , composite material , electrode , engineering , electrical engineering , chemistry , geometry , mathematics , economics , macroeconomics
We report the advances made in electrochemical machining of access holes through sheet metal during FY2005. The cutting tool underwent a major engineering re-design to accommodate an oblong cut with parallel sides (1.5'' spacing) on a surface of arbitrary curvature. The solid cathode was replaced by an array of separately movable steel pins, allowing the tool to conform to the surface shape of the work piece prior to beginning cutting. Preliminary cuts through a hardened steel drum (0.04 inch thickness) were successfully completed at a low current (50A) but the current efficiency of the cutting process was poor (<30%). Efficiency was improved to 75% and the cutting time reduced to 8 minutes in heated electrolyte at 100 A and 4.5 V. This work led to improvements in process simplicity and ease of operation: (1) continuous movement of the cathode towards the work piece was eliminated in favor of a fixed cathode; (2) the surfaces of the cutting pins do not require insulation; (3) a spider support for the tool provides for rapid positioning of the cutting tool; (4) negative electrolyte pressure minimized leakage into the drum following breakthrough. We found no reactivity of various HE's with alternative candidate ECM electrolytes