Abstract
The failure of Ti-6Al-4V components caused by poor surface integrity is a challenging problem in micro-EDM field. This paper presents a novel micro-EDM method adopting two-dimensional ultrasonic circular vibration (UCV) electrode instead of traditional rotating electrode, aiming to enhance the Ti-6Al-4V surface integrity from the perspective of increasing relative velocity between electrode and workpiece. The driving device for UCV electrode is developed and its working principle is analyzed. Based on simulation as well as experimental works, the integrity of surface machined by UCV electrode and rotating electrode are comparatively investigated. Results show that the sliding phenomenon of heat source generated in single pulse discharge is enhanced, thus the temperature gradient on machined surface is decreased. Meanwhile, the discharge energy in successive discharges becomes more consistent, which is beneficial to reduce the size fluctuation of discharge craters. In addition, the UCV electrode is helpful to suppress the abnormal discharges under the condition of ultra-high pulse frequency, thus the occurrence of long arc can be effectively prevented. As a result, the surface integrity are significantly improved in terms of surface roughness, residual stress and debris adhesion when UCV electrode is used, the phenomena of concentrated discharges and local surface ablation have also been effectively avoided. This study is expected to provide a new thought to improve the micro-EDM performance by lowering the surface defects.
Published Version
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