Abstract—In the process of Electrochemical Machining (ECM), the electrolyte renewal is likely to be poor as the machining gap is too narrow, so that the machining accuracy and surface quality are influenced, especially in the electrochemical trepanning of special structures, such as the rectangular groove with inner cylinder. As the flow field in the machining gap is difficult to be uniform, the machining quality is low and the cylindrical taper angle is large. Based on the abovementioned difficulties in ECM process, this study used ECM with mask and ECM with tool sinking, as well as the methods with and without ultrasonic vibration assisted sidewall-insulated electrodes, to conduct a comparative experiment on the electrochemical trepanning of rectangular groove with inner cylindrical structure for SUS304 stainless steel cylindrical workpieces. This study also discussed the effects of different ECM trepanning processing methods on the quality characteristics, such as cylindrical taper angle and surface morphology. The research results showed that in comparison to the ECM with mask, ECM with tool sinking had a smaller cylindrical taper angle and better surface morphology. When the ultrasonic vibration assistance was used for ECM with tool sinking, the uniformity of the flow field was improved. The electrolyte pressure changed rapidly in the processing area with the ultrasonic vibration assistance, resulting in pumping effect and cavitation effect, both of which disturbed the electrolyte, and promoted the renewal of the electrolyte in the machining gap. As a result, the resistance within the machining area is reduced, a smaller cylindrical taper angle was obtained, and the flow marks at the bottom of the rectangular groove were significantly reduced. Moreover, the surface morphology and surface roughness of the rectangular groove with inner cylinder after processing were better.

Keywords—electrochemical trepanning, rectangular groove with inner cylinder, ultrasonic vibration assistance, sidewallinsulated electrode

Cite: Chun-Hao Yang, Tzu-Yuan Chu, A-Cheng Wang, Yan-Cherng Lin, and Hai-Ping Tsui, "Ultrasonic Assisted Electrochemical Trepanning of Rectangular Groove with Inner Cylindrical Structure," International Journal of Mechanical Engineering and Robotics Research, Vol. 13, No. 6, pp. 558-565, 2024.

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