非傳統加工－電化學機械拋光研究

A Fundamental Research on ElectroChemical Mechanical Polishing (ECMP)

何效聰(HO HSIAO TSUNG)

指導教授 ： 李碩仁

元智大學/工程學院/機械工程學系/碩士(2000年)

摘要

有鑑於國內模具業界在最後的模具拋光部份，大量依賴手工來拋光，導致模具成本提高、效果不彰。故本論文的主要目的在於利用電化學加工(ECM)原理及機械研磨作用做個有效的結合與運用以改善拋光效率。克服眼前模具業界手工拋光效率不佳的缺點。
首先針對平面及曲率半徑較大的模具設計電化學機械拋光(ECMP)專用磨頭，並自行建構相關實驗器材及設備，完成基礎研究的整套系統。針對模具業常用之鋼材，選用SKD11、SKD61、Ｓ45Ｃ、SUS304來進行一系列電化學的基礎分析及拋光實驗，實驗可分為：靜態實驗及動態實驗。
透過靜態實驗了解到鈍化膜在適當的低電流密度下才會生成，且肉眼可見。硬度實驗中了解到當鈍化膜生成時，工件表面硬度有所下降，印證了鈍化膜有助於拋光效率的提升。而膜厚實驗則可以粗略的了解鈍化膜的厚度範圍，印證了膜厚很薄不易測量的事實。
藉著動態的對比實驗，證明電化學機械拋光效率優於機械拋光及機械加水拋光。且電化學機械拋光僅需1/3時間，即可達相同之粗糙度效果。最後利用田口式實驗設計{L9(34)}、變異數分析及S/N比了解因子間的貢獻度為何，並尋求最佳的實驗參數，進一步提升電化學機械拋光的效能。表面粗度可由Ra 0.3μm下降至Ra 0.1μm。

關鍵字

非傳統加工 ； 電化學 ； 拋光 ； 電化學機械拋光

並列摘要

Most of domestic die/mold manufacturers use manual polishing during the final part of die production. It lowers their productivity and also increase production cost .To overcome the above mentioned difficulties, the main objective of this thesis is to perform a fundamental research on ElectroChemical Mechanical Polishing (ECMP) which is a combination of the principle of ElectroChemical Machining (ECM) process and mechanical Polishing (MP). To understand the inner mechanism of ECMP process and the prominent effects of process parameters on the quality and efficiency of die polishing.
Fundamental electrochemestry analysis and polishing experiments were conducted on SKD11, SKD61, S45C and SUS304, the most used die steel materials. From the static experiments (fundamental electrochemistry analysis). We study the conditions under which the membrane of passivation may occur. From the dynamic experiments (polishing experiment), we studies the efficiency of the ECMP process on polishing. It has been demonstrated the efficiency was improved by as much as 2/3. Taguchi method was employed to conducts experimental design to evaluate the effect of process parameters on the efficiency of the process, roughness of the workpiece, attrition of the polishing head. The results show good potential of the ECMP on die/mold polishing.

並列關鍵字

ECMP ； ElectroChemical ； Polishing

參考文獻

[5] Tam, S. C. et al., "Electrochemical polishing of Biomedical Titanium Orifice Rings", J. Maters. Proc. Tech., Vol. 35, pp. 83~91, 1992.

[6] M. A. Bejar and F. Gutierrez, "On the detremination of current efficiency in electrochemical machining with a variable gap", J. of Maters. Proc. Tech., Vol. 37, pp. 691~699, 1993.

[9] B. Wei, K. P. Rajurkar, and S. Talpallikar, "Identification of interelectrode Gap Sizes in Pulse Electrochemical Machining", J Elec. Soc., Vol. 144, No.11, Nov, pp. 3913~1919, 1997.

[14] K. P Rajurkar, D. Zhu, B. Wei, "Minimization of Machining Allowance in Electrochemical Machining", Annals of the CIRP, Vol.47, jan, pp. 165~168, 1998.

[15] A. K. M. De Silva, J.A. McGeough, "Process monitoring of electrochemical micromachining", J. of Maters. Proc. Tech. 76. pp.165~169, 1998.