Ultrasonic vibration -assisted electrical discharge machining on Fe-based metallic glass by adding conductive powder

• Main Authors: Pei-Hao Lee, 李培豪
• Other Authors: 崔海平
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/w94248

碩士 === 國立中央大學 === 機械工程學系 === 107 === This study is the use of ultrasonic-assisted electrical discharge machining(EDM) process on Fe-based metallic glass. The negative graphite powder or conductive aluminum powder were added into the working fluids to develop innovative EDM process for obtaining precision processing technology, improving the surface roughness and enhancing the stability of processing. The processing parameters include peak current, duration time, ultrasonic power, conductive powder type and processing fluid type. After completing the experiments, the quality characteristics such as surface roughness, processing time and electrode wear quantity were also analyzed. XRD was used to analyze the crystallization phase identification. SEM was used to observe the surface microstructure and the metamorphic layer of the processing zone. The result of EDM experiment in oil shows that the combination of parameters include peak current 0.8A, duration time 100µs, ultrasonic power level 2, and graphene powder concentration 1.0×10-2wt%, the processing time is markedly shortened by 42%. Besides, when the peak current is 0.8A, the duration time is 100µs, the ultrasonic power is level 2 and addition of aluminum powder concentration 1.0×10-2wt%, the surface roughness markedly decreased by 58%. The result of EDM experiment in water shows that the combination of parameters include peak current 0.8A, the duration time 100µs, the ultrasonic power level 4 and the aluminum powder concentration 1.0×10-2wt%, the surface roughness decreases by 80%. The ultrasonic vibration-assisted method can improve the EDM process stability, increase material removal rate and improve surface roughness effectively. Through XRD phase identification analysis, the surface of the workpiece generated the crystalline phase layer (C and Cr23C6 phase) after EDM processing without conducting powder adding. The surface of the workpiece maintained amorphous material after EDM processing with conducting powder adding.