Improvement on leveling ability in counter-rotating electrochemical machining by using a variable voltage

Abstract

Roundness error plays an important role of rotating parts in engineering fields and it has a significant influence on the machining quality and accuracy during electrochemical machining (ECM) process. The precision ECM could be processed only if the initial roundness error is decreased or eliminated and the inter-electrode gap (IEG) becomes steady after reaching an equilibrium state. However, a constant voltage is generally used in ECM process. And a long time and a large allowance are required to level the profile error of workblank if the initial profile error is large. In this study, the focus herein is on the acceleration of the leveling process of the rotary workpiece. A counter-rotating electrochemical machining (CRECM) process method with a variable voltage is proposed to improve the leveling ability. For a rotary workpiece with elliptical contours, the machining voltage can be dynamically adjusted based on the IEG through the approximate regulation of sine waves according to modeling-based analysis. The method aims to improve the leveling ability by expanding the difference in the magnitude of electric current between the high and low points on the profile of the anode workpiece under different voltages. The results of experiments confirmed that the proposed method significantly reduced the leveling time from 36 to 7 min (by 81%), and the depth of dissolution of the highest point on the profile from 1.68 to 0.45 mm while reducing the roundness error from 0.5 to 0.05 mm. The leveling ratio increased from 0.26 to 0.99.