The Influence of Electrolytic Products on Electrolyte Flow Rate in Electrochemical Machining

Abstract

Electrolytic products yielded during ECM such as metallic ions, their oxides and hydroxides on the anode and hydrogen bubbles on the cathode form concentration boundary layers as they are carried away by the electrolyte flow. The products increase drag force along the flow passage to reduce the flow rate. When the machining current and the tool feed are simultaneously stopped during ECM by the same electric signal, the concentration boundary layers disappear within a few miliseconds, resulting in gradual increase of the flow rate until a new equilblium. In those circumstances some experiments and hydraulic analysis are performed in this paper. The main results are as follows.
(1) The influence of the electrolytic products on electrolyte flow rate increases with the machining time.
(2) The linear relationship is recognized between Δλ and IC/Q, where Δλ is apparent increase of skin friction coefficient, I machining current in amperes, C evolution rate of hydrogen gas (= 0.116 cm³/coul.), and Q flow rate in cm³/s.