---

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.

---

Today, the application of materials such as glass has been widely developed in the manufacture of micronutrients, electronics and medical equipment because of its high hardness, chemical resistance and high abrasion. But due to high hardness and low toughness, mechanical machining cannot be applied. The Electrochemical discharge method is a new machining method that is capable of machining hard and non-conductive electrical materials such as glass. In the process of electrochemical discharge drilling, the dimensional accuracy of the hole and especially its inlet area is important. But almost, the inlet of the hole has a high slope, which leads to excessive hole overcut and tapering of the hole side wall. In this study, to remove the high slope entrance area, a thin intermediate part was used which will be separated from the main workpiece after the drilling process. The results showed that mentioned method reduced the entrance overcut of the hole by 50 to 76% depending on the diameter of the tool. Also, the hardness measuring of points on the hole inlet showed that using the intermediate part led to the smaller heat-affected zone (HAZ) around the hole entrance. 

---

Today, the application of materials such as glass has been widely developed in the
manufacture of micronutrients, electronics and medical equipment because of its high
hardness, chemical resistance and high abrasion. But due to high hardness and low
toughness, mechanical machining can not be applied. The Electrochemical discharge
method is a new machining method that is capable of machining hard and non-conductive
electrical materials such as glass. In the process of electrochemical discharge drilling, the
dimensional accuracy of the hole and especially its inlet area is important. but almost, the
inlet of the hole has a high slope, which leads to excessive hole overcut and tapering of the
hole side wall. In this study, to remove the high slope entrance area, a thin intermediate part
was used which will be separated from the main workpiece after the drilling process. The
results showed that mentioned method reduced the entrance overcut of the hole by 50 to
76% depending on the diameter of the tool. Also, the hardness measuring of points on the
hole inlet showed that using the intermediate part led to the smaller heat-affected zone
(HAZ) around the hole entrance.