Papers by Author: Xiao Kang Liu

Abstract: A system of ultrasonic combined with grinding has been designed, and one novel connective method of straight screw combined with taper surface has been applied in spindle, so compact size and high revolving accuracy can be achieved. Modal analysis of ultrasonic vibration system has been implemented by FEM (Finite Element Method), and its optimal dimension has been calculated to find out optimal vibration estate. Full-bridge converter has been applied in driving circuit of ultrasonic vibrator, and auto-frequency tracking has been designed in order that ultrasonic vibration works on resonant or quasi-resonant frequency. Finally, machining experiments have been fulfilled about ultrasonic combined with grinding, and its machining effect has been distinctly improved comparing ordinary grinding machining.

Abstract: A nanosecond pulse power supply for micro-ECM (Electrochemical Machining) has been developed, and the minimum pulse on-time is 50 ns. After the influence of ultra-short pulse on micro-ECM was analyzed, complementary chopper circuit was presented to avoid waveform distortion, which can achieve higher pulse frequency. A fast protect circuit was designed, and its response time is less than 5μs, which can avoid damaging workpiece and electrical components by switching off machining voltage and step motor as soon as a short circuit was detected. A series of ECM experiments using the power supply have been carried out, and results of test have proved that high frequency, short pulse width power supply helps to achieve better quality surface, higher machining accuracy.

Abstract: In order to improve machining accuracy and surface quality effectively in ECM (electrochemical machining), a novel pulse inversion power supply has been presented, which has following merits such as high-frequency short pulse, high-power, and compact size. The scheme of full bridge inversion has been selected in this power supply model, and feedback circuit realizes voltage adjusted automatically, and guarantees to stability of voltage. Protect circuit has designed to avoid the problem of workpiece-burn. Finally, a series of electrochemical mechanical polishing tests using the power supply have been carried out, and the results have proved that it helps to achieve well surface quality processed, and improve machining accuracy, and also verify feasibility of its scheme.