Quantitative analysis of bubble size and electrodes gap at different dielectric conditions in powder mixed EDM process

Powder mixed EDM is getting popularity due to its improved machining efficiency. The properties of powder particles play an important role in influencing the process. Therefore, the present work is focused on the phenomenon of electrical discharge machining (EDM) process for different dielectric conditions. Experiments on EDM have been performed using plain deionized (DI) water, nonconductive Al2O3 powder mixed DI water, and conductive Al powder mixed DI water as the dielectric. The experimental result shows that the conductive powder mixed EDM process is more stable and is able to generate better surface topography compared to other processes. To explicate the observation, sparking behavior, bubble formation, and interelectrode gap (IEG) for the different dielectric conditions have been investigated using high-speed camera. The average interelectrode gap was measured as 0.05 mm, 0.1015 mm, and 0.1392 mm in conventional EDM, nonconductive alumina powder mixed EDM, and conductive aluminum powder mixed EDM process, respectively. Similarly, mean sizes of bubble diameter in conventional EDM, alumina powder mixed EDM, and aluminum powder mixed EDM are observed as 0.1583 mm, 0.17789 mm, and 0.20621 mm, respectively.