Investigation on modified jet electrochemical machining of micro-channel

Micro-channels have been widely used in variety of devices including bipolar plate, micro-chemical reactor, and micro-heat pipe. Electrochemical machining (ECM) is a promising approach to manufacture such structure on metallic surface. This paper proposed a modified jet-ECM for generating micro-channels. A flexible insulated mask with micro-through-holes was covered on the head surface of a metallic nozzle. During machining, the mask on the modified nozzle was contacted with the workpiece, and the jetting electrolyte in the nozzle was divided into different machining regions by the micro-through-holes in the mask; then, the micro-channels could be generated by moving the workpiece with an effective voltage applied between the nozzle and workpiece. Compared with traditional jet-ECM, the machining region in this method could be confined by the micro-through-hole, which was efficient for generating channel in micro-scale. In addition, multiple micro-channels could be generated by using a mask with a single row of micro-through-holes rather than assembling multiple nozzles. The experimental results showed that the pulse duty cycle has a significant influence on the dimension of micro-channel, while the pulse frequency has slight influence in contrast. In addition, the material removal rate (MRR), effective material removal rate (MRRe), and current efficiency (CE) were investigated with different machining parameters. The results indicated that although MRR was increased with the increasing pulse duty cycle, both MRRe and CE were reduced, leading to a deviation between the theory and experiment. The moving speed of workpiece also has a significant influence on CE. Increasing moving speed was useful for enhancing the CE, from 0.48 to 0.66 with the moving speed increasing from 20 to 80 μm/s. Finally, several kinds of micro-channels such as multiple micro-channels, micro-reactor, and cross micro-channels were well manufactured with this method, demonstrating a flexible and efficient process.