Mechanism Design of Magnetic-Assistance in Surface Finishing of End-Turning

Abstract

A new mechanism design using a magnetic force with high efficiency to assist discharging dregs out of the electrode gap during the electrochemical finishing on the surface finish process that follows end-turning is investigated in the current study. Through simple equipment attachment, magnetic-assistance during electrochemical finishing can follow the cutting process on the same machine. This process can be used for various end-turning operations. Among the factors affecting electrochemical finishing, the magnetic-assistance is primarily discussed. The experimental parameters are chemical composition and concentration of the electrolyte, flow rate of the electrolyte, initial gap width, current rating, on/off period of pulsed current, feed rate of workpiece, rotational speed of workpiece and electrode, magnetic strength, and distance between the two magnets. A higher current rating with magnetic-assistance reduces the finishing time and avoids the difficulty of dreg discharge. Providing a large magnetic field intensity or using a small distance between the two magnets produces a larger magnetic force and discharge ability and better finishing. A large rotational speed of the workpiece and electrode produces better finishing. Pulsed direct current can slightly promote the effect of electrochemical finishing, but the current rating needs to be increased. The magnetic-assistance during the electrochemical finishing process makes a great contribution in a short time by making the surface of the workpiece smooth and bright.

Controlled Phase Interactions Between Pulsed Electric Fields, Ultrasonic Motion, and Magnetic Fields in an Anodic Dissolution Cell

“…Additionally, cavitation from ultrasonic velocity can inhibit the formation of a passivation layer, which also increases the MRR [4]. Magnetic field assistance is typically generated using permanent magnets [11][12][13]. In these permanent magnet implementations, the field variations are created using a rotary motion of either the magnets [11], the workpiece [12], or both [13].…”

“…Magnetic field assistance is typically generated using permanent magnets [11][12][13]. In these permanent magnet implementations, the field variations are created using a rotary motion of either the magnets [11], the workpiece [12], or both [13]. When electromagnets are employed, they typically function using either direct current [14] or a low frequency alternating current [15].…”

“…The literature has also shown the benefits of dual-assisted anodic-dissolution processes that combine two different assistances [11][12][13][17][18][19][20]. Pa [17,18] studied the effect of combining pulsed electric fields with ultrasonic vibrations, each at a different frequency, to improve surface roughness (Ra).…”

“…Ultrasonic vibrations have been combined with oscillating magnetic fields to improve ECF/P, though the waveform frequencies of the two assistances were vastly different [20]. Pa [11,12] also combined an oscillating magnetic field with pulsed electric fields to improve surface quality. However, the phasing between the two waveforms was not considered in those studies.…”

“…In order to control the coupled effects between multiple assistances, the influence of the phase difference, relative frequency, and relative orientation between the assistances must be carefully investigated. While the studies in the literature have considered the direction of the input waveforms [12,13,17,18,20], the effects of the relative frequency and phase difference have been ignored. This is largely because the frequencies of the assistances used in those studies differed significantly.…”