Electrical discharge turning by assistance of external magnetic field, part I: Study of MRR and dimensional accuracy

Abstract

Hybrid machining process is increasing its importance toward processing of advanced materials with complex geometries. Electrical discharge machining is a type of non-conventional machining process that is extensively used for creating micro and macro features in hard material. The process has capability to be used for flat samples and round bars that former application is more common. In the present study an experimental work has been made to produce sharp edge grooves in round bard made of AISI D2 by electrical discharge turning process. To do so, an external magnetic flux density has been applied around machining gap to enhance the performance measures. Series of experiments have been carried out in order to find effect of magnetic flux density (0, 0.2 and 0.4T), discharge current (5, 10, 15A), pulse on time (600, 800 and 1000μs), and work rotational speed (50, 150 and 250RPM) on material removal rate (MRR) and overcut (OC). Finally optimization has been carried out in different machining modes to find how the optimum value of magnetic field is varied in roughing and finishing. Results indicated that irrespective to the machining regime, application of high intensity magnetic field (i.e. 0.4T) is dominant in increasing the machining rate as well as enhancing the dimensional accuracy. Therefore, the method can be useful for performing the electrical discharge turning process.

Keywords

• Electrical discharge machining
• Magnetic field
• MRR
• Dimensional accuracy
• Surface integrity