| dc.description.abstract | During the electrochemical machining(ECM) of the micro-hole array by using array electrodes, the poor processing accuracy or inability of the process resulted from the problems of the poor supply of electrolyte which are resulted from the inability to rotate multiple electrodes at the same time and the inability to design a flow channel in the electrodes. To overcome these difficulties, ultrasonic vibration and magnetic field were adapted to assist through-mask electrochemical machining of the micro-hole array in this study. The one-piece array electrode assisted by ultrasonic vibration and a magnetic field was used to produce a micro-hole array on SUS 304 in the ECM process. Discussions follow on the influences of the various processing characteristics, such as average diagonal length, diagonal length range, inlet taper angle, and outlet taper angle, which resulted from the various processing parameters, including ultrasonic power level, working voltage, pulse off time, and electrode feed rate.
The experimental results have shown that the ultrasonic vibration-assisted electrodes quickly changed the pressure of the electrolyte, producing a pumping effect and a cavitation effect, and the interaction between the magnetic field and the electric field generated a Lorentz force. These auxiliary methods promoted the renewal of the electrolyte into the machining gap, which quickly excludes the reaction heat and the non-conductive dark brown metal oxide in the processing area, thereby improving the processing ability and material removal rate and reducing the average diagonal length of the micro-hole array. When ultrasonic and magnetic field assistances were applied simultaneously, better average diagonal and surface qualities were obtained compared with the ultrasonic assistance or magnetic field assistance independently. The experimental parameter combination, including ultrasonic power level 8 (amplitude: 1.30 μm), working voltage 16 V, pulse off time 70 μs, and tool electrode feed rate 7 μm/s, resulted in a minimum average diagonal length of 546 μm and the smallest diagonal length range of 25 μm while improving the inlet and outlet taper angles of the micro-holes. | en_US |