應用放電複合製程之微凹型球面的拋光研究

A study on micro-spherical cavity polishing in micro-EDM hybrid process

羅亦琥(Yi-hu Lo)

指導教授 ： 顏炳華

國立中央大學/工學院/機械工程學系/碩士(2008年)

摘要

在精微加工的領域中，微放電加工法可運用於各種高精密微型模具的製造，但因放電加工時的高溫熔融現象，造成放電加工所製造出的模具表面，具有放電坑與微裂痕等缺陷，嚴重影響微型模具的表面品質。有鑒於此，本研究擬以電泳沉積法和電解拋光，分別作為放電加工後之複合製程，並以模具鋼SKD61為工件材料，對碳化鎢微球狀電極放電加工後製作出直徑約100μm、深度約25μm的微凹型球面模具，進行模穴表面精微拋光，期能改善模穴表面品質，以達到高品質微凹型球面模具的需求。
實驗結果顯示，在進行電泳拋光時，以電壓5V、SiC磨粒濃度10%、電泳液為pH 9，經1分鐘的沉積後，將可使SiC磨粒有效沉積於碳化鎢球狀電極表面，再以轉速3000rpm，對放電過後的微球面模穴表面進行10min拋光後，可將模穴表面粗糙度值由Rmax 3.183μm（Ra 0.198μm），改善至Rmax 0.448μm（Ra 0.037μm）。在以電解電壓1.5V，加工時間30sec，對放電過後的微球面模穴表面進行電解拋光後，可將模穴表面粗糙度值改善為Rmax 0.819μm（Ra 0.026μm）。

關鍵字

微放電加工 ； 電泳沉積 ； 電解拋光 ； 微凹型球面模具

並列摘要

In this study, using micro-electro-discharge-machining (micro-EDM) combined with electrophoretic deposition (EPD) and electropolishing (EP) to machine a micro-spherical cavity in SKD61. During the machining process, a micro-spherical tool is built by wire electro-discharge grinding, spherical forming directly by using micro-EDM for machining the micro-spherical cavity that is polished by EPD and EP.
In the first stage of the study, EPD process, the polishing characteristics of electro discharge machined cavity surface in electrophoretic deposition are investigated. The experimental result shows that the initial roughness of electro-discharge machined cavity surface could be improved from 3.183μm Rmax(0.198 μm Ra ) to 0.448μm Rmax (0.037 μm Ra ).
In the second stage of the study, EP process, the parameters of electrolytic voltage and electrolytic time are addressed. The result shows the initial roughness of surface could be improved from 3.183μm Rmax(0.198 μm Ra ) to 0.819μm Rmax (0.026 μm Ra ).

並列關鍵字

Micro-spherical cavity. ； Micro-EDM ； Electrophoretic deposition ； Electropolishing

參考文獻

1. H. Huang, H. Zhang, L. Zhou and H. Y Zheng “Ultrasonic vibration assisted electro-discharge machining of microholes in Nitinol ” J. Micromech. Microeng.,Vol 13 ,pp. 693–700, 2003.

2. S. S. Choi, Jung, D. W. Kim, M. A. Yakshin, J. Y. Park and Y. Kuk, “Frabrication and microelectron gun arrays using laser micromachining” Microelectronic Engineering 41/42, pp.167-170, 1998.

3. D. M. Allen, A. Lecheheb, “Micro electro-doscharge machining of ink jet nozzles, optimum selection of material and machining parameters”, Journal of Materials Processing Technology, Vol 58, pp53-66, 1996.

4. X. Q. Sun ,T. Masuzawa , M. Fjino, “Micro ultrasonic machining and its applications in MEMS”, Sensors and actuators, A57 ,pp159-164 ,1997.

5. W. Ehrfeld and H. Lehr, “Deep X-Ray Lithography for the production of three-dimensional microstructures from metals”, Polymers and Ceramics, Vol. 45 No.3, pp349-365, 1995.