Reducing stray corrosion during co-rotating electrochemical machining of an inner-wall grid by regulating the electrolyte flow using a cathode with multi-orifice outlet structure

Stray corrosion is a common problem in electrochemical machining (ECM) and represents one of the primary factors currently limiting its widespread application in the manufacturing of thin-walled annular components in the aerospace sector. Among the contributing factors, the electrolyte outlet structure within the cathode tool is a key component affecting machining uniformity and stray corrosion, which in turn impacts machining precision. However, although a number of different outlet structure designs are available, their specific influence on machining uniformity and stray corrosion remains poorly understood. In this study, dense-slit, sparse-slit, and multi-orifice cathode outlet structures were comparatively investigated through three-dimensional flow-field and electric-field simulations and machining experiments. The results showed that the multi-orifice structure produced a more uniform electrolyte velocity and current-density distribution while reducing electrolyte coverage and stray current near the machining-zone boundary. Under the investigated conditions, the multi-orifice cathode achieved a wall-thickness error of less than 0.1 mm and a grid-sidewall inclination of 1.91°. The top-wall corrosion was reduced by 45.6% compared with that obtained using the dense-slit structure. These results indicate that the multi-orifice outlet provides an effective approach for improving the machining uniformity and edge-profile accuracy of ICRECM.