Machining Characteristics of Diamond Grit-Coated Tools in Grinding-Aided ECDM

This study investigated the machining characteristics of two shapes of diamond grit–coated tools used in grinding-aided electrochemical discharge machining for optical glass drilling. The effects of roundness, machining accuracy, surface roughness, and tool wear under various machining depths and electrode rotating speeds were explored, and the bubble generation mechanism and its effects on the discharge current waveform and electrochemical discharge reaction were observed. This study revealed that the bubbles generated in the gaps between diamond particles combine with each other to form a stable bubble film. Owing to differences in bubble generation mechanisms, the discharging waveform of the diamond grit–coated tool was more stable than that of tools without diamond grit–coated. It is known from the experimental results that the diamond grit–coated ball end mill in this method minimized shape roundness errors, machining time and the fracture of the exit edge.