Machining of hard materials by the EDM combined Ultrasonic Vibration Method

摘要

In the electrical discharge machining (EDM) of cemented carbide material, the material removal rate (MRR), tool wear ratio (TWR) and surface roughness is inferior to other electrical conductive materials. To solve this problem, we introduce a new method referred to as combined ultrasonic vibration. Complex vibration of the tool electrode system was used for the EDM to result in a higher MRR, lower TWR and improved surface roughness values for machining. To obtain a finely machined surface, the experiments were performed under the finishing conditions. The effects of ultrasonic longitudinal, bending and complex vibration on machining efficiencies were investigated. A negative polarity of the tool electrode was used in the tests. The discharge waveform generations were analyzed and associated with the machining properties. Additionally, the surface roughness as well as the diameter and depth of the discharge crater were observed. The results show that the ultrasonic vibration assisted in an increase of the MRR. The MRR of the complex vibration was about four times higher than the EDM with no rotation (EDM-NR) and was two times higher than the EDM with rotation (EDM-R). The normal discharge generation numbers increased when the ultrasonic vibration was applied. The effects of the bending vibration caused the diameter of the craters to become large and shallow.