Magnetic Field Assistance in the EDM Process

Abstract

This chapter discusses one of the methods employed in traditional electric discharge machining (EDM) for the enhancement of machining efficiency, that is, magnetic field assistance (MFA) in the EDM process. It is defined as a hybridization of the EDM process, which brings productivity enhancement by triggering debris removal during the machining. Essentially there are two aspects of the magnetic field-assisted EDM (MFAEDM) process that are included in this chapter. The first aspect is related to debris evacuation for the machining of magnetic materials (ferromagnetic materials) whereby the magnetic field force assists in the efficient removal of debris from the narrow inter-electrode gap (IEG). It facilitates improved machining performance by eliminating abnormal discharges during the machining operation. Another aspect is the machining of non-magnetic materials (such as copper, aluminum, tungsten carbide, titanium and its alloys, and so on.), the debris of which is not influenced by magnetic field forces. However, the plasma dynamics, which involves electron density, mean free path of electrons, plasma confinement and melt pool are influenced by the applied magnetic field that results in the enhancement in machining performance for the machining of non-magnetic materials. This chapter includes the fundamental role of MFA in the EDM process for both magnetic and non-magnetic materials. A brief introduction of commonly applied debris flushing techniques in EDM are discussed. The influence of magnetic field addition in EDM is analyzed in terms of material removal from electrodes, surface characteristics and the aspect ratios of the features. Moreover, the application of MFA in different variants of EDM is also highlighted. A fishbone diagram of the process, limitations, future scope/research opportunities, and so forth, are included in the chapter.