| dc.description.abstract | This study employed high-power ultrasonic vibration-assisted wire electrical discharge machining for creating grooves on SiC wafers. The influence of processing parameters open voltage, ultrasonic power level, wire tension level, and SiC wafer thickness on the machining time, material removal rate, and kerf width was investigated. Furthermore, the depth of the heat-affected zones was measured after the processing, and the effects of ultrasonic vibration-assisted processing and processing without ultrasonic vibration assistance on the SiC wafer material were determined.
The experimental results revealed that when the thickness of the SiC wafer workpiece was 0.42 mm, a better result was obtained when ultrasonic vibration assistance was not applied than when it was. This was because in the processing without ultrasonic assistance, the lateral vibration of the wire electrode was small, meaning that the discharge phenomenon exhibited a parallel direction to the wire electrode; thus, the frequency of lateral discharge was not increased, and the wire electrode was operated for less time in the processing area. When using the most appropriate combination of processing parameters, the processing kerf width was 8% lower, the machining time was 22% shorter, and the material removal rate was 12% higher for nonassisted processing than for ultrasonic vibration-assisted processing.
When a SiC wafer workpiece with a thickness of 10.0 mm was used in the processing experiments, the opposite result was obtained processing with ultrasonic vibration assistance was better than that without. This was because the ultrasonic waves helped vibrate the wire electrode, and this added vibration accelerated the removal of debris, leading to less-concentrated discharge. When processing thicker SiC wafer workpieces by using ultrasonic vibration assistance with an appropriate combination of processing parameters led to 10% lower processing kerf width, 13% shorter machining time, and an 8% higher material removal rate when compared with processing without the assistance. The heat-affected depth was shallower, and a minimum heat-affected depth of 2 μm could be obtained. | en_US |