Electrochemical discharge machining (ECDM) is a nontraditional machining process applied to nonconductive and brittle materials such as glass and ceramic. In recent years, investigations have focused on improving machining efficiency, especially the material removal rate (MRR). In this regard, different techniques, including chemical and physical phenomena, have been employed on different components of the ECDM system. Current research applies a new and straightforward method to improve the MRR without the consequent complexity of other techniques (improved machining efficiency). In this way, the machining process applies in two sequential passes (double-pass machining) to shape the final geometry. In the typical ECDM process, the whole geometry is machined by one pass process. Results showed that by employing the double-pass technique, the maximum depth reached 660 µm, which was 35% higher than the single-pass (SP) process (the total machining time of SP was the same as double-pass). In addition, a significant average improvement percentage of 45% was achieved. The optimum diameter difference of the tools in the double-pass process was 300 µm, which led to the highest depth values. Depending on the tool changing time, the double-pass process is economically efficient in machining depths of more than 250 µm.

Keywords