Chemically strengthened glass has recently gained attention for use in mobile device display covers due to its enhanced mechanical properties. However, cutting chemically strengthened glass poses challenges because of its high surface compressive stress, derived from the ion exchange between Na+ and K+ during the strengthening process. To address this, we propose an efficient method for cutting chemically strengthened glass by integrating electrochemical discharge (ECD) and grinding processes. The ECD process helps alleviate surface compressive stress through reverse ion exchange, while the grinding process helps mitigate compressive stress on the bottom surface without flipping the glass. Chemical composition analysis of the cross-section of glass cut along the line treated by the ECD process revealed that this method can induce reverse ion exchange on both the upper and bottom surfaces of chemically strengthened glass. Furthermore, nano-indentation hardness tests conducted on the cross-section demonstrated that the subsurface hardness could be reduced by the ECD process, indicating a relaxation of the surface compressive layers. It has also been proven that chemically strengthened glass can be successfully cut using this method, suggesting it offers a viable solution for efficient glass cutting.

Electrochemical micromachining (ECM) processes use anodic dissolution of metals to remove workpiece materials. ECM processes including electrochemical milling and drilling, wire electrochemical machining and electrochemical etching offer a better alternative in manufacturing complex features and nano-pattern surface. Electrochemical discharge machining (ECDM) uses high temperature of electrochemical spark, which is suitable process for micro machining of hard brittle and non-conductive materials such as glass and ceramic. In this paper, the state of the art in electrochemical micro machining technologies was reviewed. Also, some hybrid machining methods are introduced.