DEVELOPMENT AND INVESTIGATION OF ULTRASONIC ASSISTED ELECTROCHEMICAL DISCHARGE MACHINING PROCESS

Abstract

Electrochemical discharge machining is a hybrid non-conventional machining process, which is used to machine electrical conductive or non-conductive materials. It is a preferred process to fabricate microproducts like micro holes, micro channels, and microgrooves on a variety of materials. However, the outcomes of ECDM have many restrictions in application due to limitations on efficiency, accuracy and machining quality. Many technical augmentations have been added to the ECDM process to improve its efficiency. But employment of each augmentation in the most efficient way is not reported. Most frequent limitation is that spark discharge frequency drastically reduces as the machining depth increases in ECDM. One of the primary reasons for this is the difficulty of sustaining an adequate electrolyte flow in the narrow gap between the tool electrode and work-piece material, which results in the significant reduction of machining depth. In this research work, ultrasonic tool vibration was used to enhance the machining depth of ECDM process by assuring an adequate electrolyte flow. Therefore the present work is based on the triplex hybridization of ECDM. Ultrasonic assisted electrochemical discharge machining setup was developed and the effect of process parameters on the performance characteristics were investigated. Pilot experiments were done to set the level of the parameters. Then after central composite design (CCD) approach was used for planning while response surface methodology (RSM) approach was used to analyse the results. By using ultrasonic vibration, ECDM efficiency increases. Depth of drilled hole increases while hole over cut and thermal damage reduces. This is due to the adequate electrolyte flow in the case of deep hole drilling, and thus improvement in the spark discharge frequency.