Study of the current signal and material removal during ultrasonic-assisted electrochemical discharge machining

Electrochemical discharge machining (ECDM) is a cost-effective machining process used to shape non-conductive materials such as glass and ceramics. The process can overcome poor machinability of hard and brittle materials. Different types of physical phenomena can be added to the ECDM components to improve the machining efficiency. As the main target of this paper, ultrasonic vibration was integrated to the cathode of the ECDM process (UAECDM), which resulted in vibration concentration only to the machining zone. In order to design the experimental configuration, modal analysis was used. Machining speed was the main output of this investigation. Gas film and electric discharge were two main physical phenomena during ECDM. The thickness of gas film, location, and pattern of discharges were determined, experimentally. Also, current signal was a useful tool that could record significant details of involved mechanisms and phenomena during machining. Images of gas film showed that the application of ultrasonic vibration decreased the thickness of gas film by 65%. In addition, the vibration amplitude of 10 μm created the most uniform current signal, which had a considerable effect on the material removal rate (MRR). Results showed that all levels of vibration amplitude increased the machining speed during discharge and hydrodynamic regimes of the machining process.