---

Electrochemical discharge machining (ECDM) is a novel non-conventional micro-machining method that can be applied to machining hard, brittle and non-conductive materials such as glass and ceramic. Due to the hardness and brittleness of mentioned materials, the application of conventional machining is associated with serious technical problems. In this article, the machining process was performed in two steps, and hole depth is considered as the main machining output. The obtained results of the new method are compared to single pass micro-drilling (a common micro-drilling process). The achieved results indicated that depth improvements of 36% and 70% were obtained for voltages of 33 and 38V. Also, by increasing the diameter difference, a deeper hole can be achieved.