Rotating short arc EDM milling method under composite energy field

Abstract

• A new EDM milling method with rotating short arcs under composite energy field was proposed. • A mathematical model to describe the trajectory of particles in the composite field was established. • Rotating short arc was generated by the Lorentz force, the electrical force and the high-speed rotation of electrode. • The MRR of rotating short arc machining is increased by 46 % compared with traditional EDM. • An increase in the strength of the magnetic field increases the MRR and decreases the TEWR. Electrical discharge machining (EDM) is a rapidly developing technique amongst nontraditional techniques. However, low processing efficiency significantly hinders its application in industry. This study proposes a new high-speed EDM milling method using rotating short arcs under a composite energy field. By the combined effect of the Lorentz force, electric field force, and high-speed rotation of the tool electrode, rotating short arcs are generated between the tool electrode and the workpiece, which in turn provide constant erosion of materials. The proposed method can increase the discharge energy density by converging the electric arcs through the composite energy field, and increase the energy obtained by the workpiece. By this means, it improves the material removal rate. During processing, a portion of debris is attracted by the magnetic field and adheres to the end surface of the electrode, which can protect the electrode and reduce the electrode wear rate. Compared with traditional EDM, the material removal rate of the rotating short arc milling was increased by 46 %, while the tool electrode wear rate decreased by 62 %. Furthermore, an increase in the strength of the magnetic field increases the material removal rate of the rotating short arc milling and decreases the tool electrode wear rate and surface roughness. Therefore, high-efficiency and high-quality EDM milling can be achieved by using the proposed method.