| 摘要: | 本論文為超音波輔助電化學加工微孔陣列之研究，採用超音波輔助振動一體式陣列電極，對301不鏽鋼試片進行陣列鑽孔加工，並探討各種加工參數如：超音波振幅、工作電壓、脈衝休止時間及電極進給速率對各種加工特性的影響如：平均對角線長、對角線長變異量、微孔入口及出口之錐角。
實驗結果顯示，超音波輔助振動電極對電解液產生週期性的壓力差，這個週期性的壓力差形成泵吸作用及空蝕作用，泵吸作用使大範圍的電解液被吸入、排出加工間隙，而空蝕作用所產生的微氣泡破裂後產生微射流高速擾動小範圍的電解液。上述兩種作用能有效的更新加工間隙內的電解液，補充電化學反應中消耗的離子，並將間隙中的固體反應產物、氣體及反應熱排出，進而提升加工速度，並降低微孔陣列之平均對角線長。當使用超音波輔助電化學加工微孔陣列時，超音波振幅由0.94μm(超音波振幅1段)提升至2.87μm(超音波振幅9段)時可提升加工速度500%以上。在超音波振幅9段(2.87μm)、工作電壓11V、脈衝休止時間50μs、電極進給速率5μm/s實驗最佳參數組合下進行加工，能夠得到最小的平均對角線長1200μm及較小的對角線長變異量44μm，並能改善微孔入口及出口之錐角。
;This thesis is an investigation of ultrasonic-assisted electrochemical machining of the micro-hole array. In this study, one-piece array electrode assisted by ultrasonic vibration is used to produce micro-hole array on 301 stainless steel plate. The effects of processing parameters such as ultrasonic amplitude, working voltage, pulse off time and electrode feed rate on quality characteristics. The quality characteristics including average diagonal length, diagonal length variation, inlet taper angle and outlet taper angle were discussed.
The experimental results indicate that the ultrasonic vibration electrode generates a periodic pressure difference to the electrolyte. This periodic pressure difference forms the pumping effect and the cavitation effect. The pumping effect causes a wide range of electrolytes to be sucked into and pushed out off the machining gap. Besides, the periodic pressure difference leads to a cavitation effect, which produces microbubbles. Once the microbubble collapse, it produces a microjet which disturbs a small range of electrolytes instantaneously. Both effects can effectively refresh the electrolyte in the machining gap, supply the ions consumed in the electrochemical reaction, and exhaust the solid reaction products, gases, and reaction heat in the gap. The phenomenon enhances the processing speed and reduces the average diagonal length of micro-hole array. By using ultrasonic-assisted electrochemical machining micro-hole array, when the ultrasonic amplitude is increased from 0.94 μm (power of ultrasonic vibration lv.1) to 2.87 μm (power of ultrasonic vibration lv.1), the processing speed can be improved by more than 500%. Processing under the experimental optimal parameter, such as the power of ultrasonic vibration level 9 (2.87μm), working voltage 11V, pulse off time 50μs and electrode feed rate 5μm/s, can obtain the minimum average diagonal length of 1200μm and smaller diagonal length variation of 44μm. It also improve the inlet and outlet taper angle of micro holes. |
