| 摘要: | 本論文為超音波輔助微電化學加工製備微梨形工具技術之研究，採用超音波輔助振動，製備碳化鎢微梨形工具。當採用線切割放電加工、燒結法等方式製備之微梨形工具時，會表面容易缺陷、高成本、需較長加工時間等問題，難以加工出尺寸精度及表面形貌較佳之微梨形工具，為了克服前述困難點，本論文設計出一三板片電極，並使用一向上噴流式電解液供給治具及超音波振動輔助，進行電化學加工製備微梨形工具，並探討工作電壓、上電極供電時間、脈衝休止時間及超音波功率格數等不同加工參數對微梨形工具整體形貌、最大徑、最小徑、橢圓長軸長1、橢圓長軸長2、消耗長、整體直徑差及橢圓度等各種加工特性之影響，並分析微梨形工具加工後之表面成分變化。
實驗結果顯示，採用超音波振動會產生泵吸作用，可加速加工間隙內之電解液更新，並快速移除加工間隙中的反應熱與各種電化學生成物，且相較於無超音波振動輔助，可得到較佳之微梨形工具形貌與較小微梨形工具尺寸。當採用本研究較佳之參數組合，即工作電壓9V、上電極板片供電時間20s、脈衝休止時間40μs及超音波功率格數15時，可得到較佳微梨形工具尺寸為最大徑181m、最小徑54m、橢圓長軸長1 168m、橢圓長軸長2 543m、消耗長1288m、橢圓度1.99與整體直徑差126m，並能有效改善微梨形工具整體形貌。
;This study prepared micro pear-shaped tools using ultrasonic-assisted micro electrochemical techniques. It used ultrasonic assisted vibration to prepare tungsten carbide micro pear-shaped tools. When wire-cutting electrical discharge machining, sintering process and other methods are adopted to prepare micro pear-shaped tools, but there are problems of likely forming of surface defects and high cost and requiring long processing time. Hence, it is difficult to process micro pear-shaped tools with better dimension precision and surface appearance. In order to overcome the above difficulties, this study designed a three-plate electrode, and employed jet flow electrolyte to supply fixture and assistance of ultrasonic-assisted vibration to prepare micro pear-shaped tools using electrochemical techniques. This study also discussed the influence of different machining parameters, such as working voltage, upper electrode power supply time, pulse off time and ultrasonic vibration stage, on various processing characteristics, such as maximum diameter, minimum diameter, ellipse major axis length 1, ellipse major axis length 2, consumption length, overall diameter difference and ellipticity. It further analyzed change of surface components of micro pear-shaped tools after machining.
Experimental results show that ultrasonic vibration has a pumping function, and it can accelerate electrolyte renewal in machining gap and rapidly remove reaction heat and various electrochemical products in machining gap. Comparing with the situation without assistance of ultrasonic vibration, better appearance of micro pear-shaped tools and smaller dimensions of micro pear-shaped tools can be obtained. Under parameter combination of working voltage of 9V, upper electrode power supply time of 20s, pulse off time of 40s, and ultrasonic vibration stage is 15, better dimensions of micro pear-shaped tools can be obtained (maximum diameter of 181m, minimum diameter of 54m, ellipse major axis length 1 of 168m, ellipse major axis length 2 of 543m, consumption length of 1288m, ellipticity of 1.99 and overall diameter difference of 126m), the overall appearance of micro pear-shaped can be improved effectively. |
