Enhancement of electrochemical discharge machining accuracy and surface integrity using side-insulated tool electrode with diamond coating
Enhancement of electrochemical discharge machining accuracy and surface integrity using side-insulated tool electrode with diamond coating
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DOI：
10.1088/1361-6439/aa6e94
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发表时间：
2017-06-01
影响因子：
2.3
通讯作者：
Zhao, Wansheng
中科院分区：
文献类型：
--
作者：
Tang, Weidong;Kang, Xiaoming;Zhao, Wansheng
电化学放电加工（Electrochemical Discharge Machining，ECDM）是一种新兴的非传统加工技术，利用工具电极周围的电化学放电现象，对玻璃、陶瓷等非导电材料进行加工。在电火花钻削过程中，暴露于电解液中的工具端部和工具侧壁均会形成气膜并出现放电。不希望的侧壁放电扩大了孔入口直径并破坏孔表面完整性。为了防止侧壁放电，在微细孔电火花加工中使用了具有4 μ m厚金刚石涂层的侧壁绝缘工具电极。由于工具侧壁上的绝缘层，气膜的形成和放电主要发生在工具端部。实验表明，与传统工具电极相比，侧绝缘工具电极加工的孔直径更小，孔入口处无明显热影响区，加工表面完整性更好。此外，随着加工深度从50 μ m增加到500 μ m，孔径几乎保持不变。侧绝缘电极具有通过减小微孔的锥角来提高形状精度的优点。当加工深度为600 μ m时，侧绝缘电极获得的孔锥角（3.3 °）比传统工具电极（6.4 °）小得多。
Electrochemical discharge machining (ECDM) is an emerging non-traditional processing technology used to machine electrical non-conductive material like glass and ceramics, by using the electrochemical discharge phenomena around the tool electrode. In the general ECDM drilling process, the gas film forms and electrical discharge appears at both the tool end and the tool sidewall that were exposed to the electrolyte. The undesirable sidewall discharge enlarges the hole entrance diameter and destroys the hole surface integrity. In order to prevent the sidewall discharge, a side-insulated tool electrode with a 4 mu m-thick diamond coating layer was used in ECDM micro-hole drilling. The gas film formation and electrical discharge mostly happened on the tool end due to the insulation layer on the tool sidewall. Experiments showed that, compared with the traditional tool electrode, the side-insulated tool electrode achieves a smaller hole diameter and better surface integrity without an obvious heat affected zone at the hole entrance. Furthermore, the hole diameter nearly remains the same as the machining depth increases from 50 mu m to 500 mu m. The side-insulated electrode has an advantage in enhancing shape accuracy by reducing the taper angle of the micro hole. When the machining depth is 600 mu m, the side-insulated electrode achieves a much smaller hole taper angle (3.3 degrees) than the traditional tool electrode does (6.4 degrees).