Machining Characteristics of a Hybrid Process of EDM in Gas Combined with Ultrasonic Vibration and AJM

This study investigated the machining characteristics of a developed hybrid process of electrical discharge machining (EDM) in gas combined with abrasive jet machining (AJM) and ultrasonic vibration (USV). The developed hybrid EDM process was adopted to examine the machining characteristics such as material removal rate (MRR), electrode wear rate (EWR), and surface roughness (SR) for SKD 61 steel through the experimental works. In this study, the compressed dielectric media such as air, oxygen, and argon were employed in the experiments to investigate the effects on material removal efficiency, surface integrity, and thickness of recast layer. The experimental results show that the hybrid EDM process obtained higher MRR. In addition, the oxygen medium could facilitate the reaction within the machining area to increase the exploding and melting effects. Thus, the MRR gained by oxygen has the highest response. The argon was an inert gas that could prevent the oxidation during the process, and the lowest EWR as well as the finest SR could be received using argon as a dielectric media in the hybrid EDM process. The ultrasonic vibration incorporated in the hybrid EDM process could effectively reduce the thickness of recast layer. In general, the different dielectric media supplied into the machining area could create various mechanisms. From the experimental results, the USV and AJM incorporated into the hybrid EDM process could obviously promote the machining efficiency and surface quality.