Papers by Author: Z.Q. Yu

Abstract: The influences of ultrasonic field to polishing performance of Polishing Based on Coupling Vibration of Liquid (PCVL) are analyzed here. The simulation results shows that sound field in the original polishing device is rather uneven due to the existence of standing wave. To obtain better polishing performance, the experimental equipment was modified. Uniformity of the sound field was improved by preventing standing wave, thus a better surface quality could be achieved. Furthermore, a higher machining efficiency could be also obtained because sound intensity was strengthened at the same time. From the results serials of experiments, the improvements made by modified equipment are clearly shown.

Abstract: Experiment research of polishing based on liquid two-dimension vibration is carried out by a vibrating device which is driven by ultrasonic source and can produce coupling vibrations of liquid. Sound pressures of some key points in water are tested by hydrophone and translated into sound intensity to evaluate the effect of input voltage of transducer. It is analyzed which vibration state of fluid field and the way that workpiece is clamped is the best for the polishing. Polishing results of quartz glass are evaluated by the use of region-track measure method, and some polishing rules are presented.

Abstract: In grinding viscous materials, such as stainless steel, aluminum and many polymeric materials, the application of a dither on the workpieces proves to be an effective way to enhance the quality of surface finish. A linear stepper motor is utilized for this purpose. By means of the PWM control to the adjacent phase coils, the linear stepper can drive the sliding table to make reciprocating motion and also to produce a desired dither signal, while the grinding is undertaken to the attached workpiece. In this paper, a linear stepper motor is introduced to drive the sliding table and a modulated control strategy is used to control the linear stepper continuously, which also generates an additional dither on the sliding table and the attached workpiece. The dither amplitude can be adjusted by means of the modulated frequency. Experiments are designed to measure the practical dither signals and to verify the effectiveness of improving surface finish quality using a dither. It is demonstrated by both theoretical and experimental results that by means of proposed table drive, a rather wide band of dither signal can be acquired and can meet the most demand of viscous material grinding.

Abstract: A novel polishing technique based on the two-dimension vibration of fluid is put forward to obtain ultra-smooth surface without damage. In operation, the polishing pad is replaced by fluid where fine abrasive particles are mixed, and the impact and grinding effect can be produced by means of the vibration of fluid and the relative motion of workpiece. It can achieve the ultra-precise polishing for all kinds of planes and curved surfaces. A finite element method is employed to analyze the dynamic behaviors, including vibration mode and harmonic response under the action of the exciter, and the fluid field based on two-dimension vibration is simulated.