Study on E ectiveness of Magnetic Field Assisted Flushing in Improvement of Process Parameters in Electrical Discharge Machining

Abstract

Electrical-discharge machining (EDM) is an electrothermal process for machining geometrically complex and/or hard material components such as heat treated tool steels, composites and super alloys. It is widely used in die and mold making, aeronautics and nuclear industries. The accumulation of debris at the spark gap region can a ect the e eciency and overall out- come of the machining process. The material removal rate, tool wear and surface roughness are all dependent on conditions at this region. Occurrence of short-circuits and arcing between the workpiece and tool electrode is a challenge faced during EDM operations. These conditions are detrimental as they greatly compromise the machining e ciency and quality of the process. The eroded debris can cause a short circuit at the spark gap. When this occurs, there is no material removal and there is risk of the tool welding on to the workpiece. Arcing may also occur when a portion of the cavity contains too many eroded debris and the electric current is discharged through them. This leads to poor surface nish and reduced material removal rate and tool life. Therefore, there is need for an e cient mechanism for optimum clearing of the spark gap of all eroded debris. This research investigated the e ectiveness of the use of magnetic energy in removal of debris from the spark gap and the in uence of application of varied levels of magnetic intensity on the various performance parameters of the EDM process. Empirical modelling and surface response methods were used for the analysis of these parameters. It was found that the introduction of magnetic force in the spark-gap region improved the pro-cess parameters by increasing the rates of material removal and reducing the surface roughness and tool wear rate.