The tool design and experiments on pulse electrochemical machining of micro channel arrays on metallic bipolar plate using multifunctional cathode.

A new constrained flow mode was developed to improve the machining stability in pulse electrochemical machining (PECM) of micro channel arrays on metallic bipolar plate. In electrochemical machining (ECM), the electrolyte flow field in the machining region is a key factor influencing processing stability and surface quality. In this study, a multifunctional cathode (MFC) was designed in the process, which was prepared with casting molding method. MFC acted as electrode, as well as sealing device and isolating individual machining regions. The channels of electrode were filled with elastic blocks, which were tightly pressed against the surface of workpiece during process to separate the large machining region into multiple independent machining regions. Therefore, the machining area would have sufficient electrolyte, and the flow field of each channel was independent from each other. 3-D flow field simulation was developed in this study to analyze the flow field of the channel arrays. It indicated that multiple independent machining regions could effectively improve the velocity uniformity of each channel. The experiments revealed that the uniformity of flow field had a positive role to prevent from spark discharge and short circuit, as well as the machining efficiency and machining stability. The channel arrays with 466-μm depth were machined on SS304 metallic BP within 2 min. [ABSTRACT FROM AUTHOR]