Boundary-tailored flow and electric fields in electrochemical milling: Experimental and numerical simulation

Abstract

Sinking electrochemical milling refers to a process where the electrode is positioned below the workpiece's surface. The primary advantage of this technique lies in its capacity to eliminate surface irregularities of the blank workpiece, enhance processing depth with a single electrode, and effectively control the reflection and flow of the electrolyte by allowing the tool electrode to sink, thereby improving machining accuracy. To address the issue of electrolyte products accumulating in the processing gap during sinking electrochemical milling, this paper introduces a novel processing method called semi-sinking electrochemical milling. This method combines the advantages of both flying and sinking electrochemical milling. In semi-sinking electrochemical milling, rectangular electrode leading edge performs flying electrochemical milling, while the trailing edge engages in sinking electrochemical milling by cutting into the workpiece. To enhance the effective processing area of the electrode's trailing edge in semi-sinking electrochemical milling, a electrode with an inclined leading edge was designed and validated. Through physical field distribution analysis, the impact of leading edge inclination angle is studied. Results indicate that increasing the leading edge inclination angle mitigates the liquid deficiency phenomenon. A higher inclination angle results in a more uniform flow field, which boosts the leading edge current density. Experimental findings demonstrate that the material removal rate is 169.90 % higher than that of standard sinking electrochemical milling electrode when the electrode is inclined angle to 60°.Additionally, there is a 121.45 % increase in the material removal rate and a 102.97 % increase in processing depth, along with a steeper section profile, compared to the standard cutting electrode with a 60° inclination angle. From a surface morphology perspective, using a electrode with an inclined leading edge reduces stray corrosion on the processed surface and achieves superior surface finish quality.