Influence Of Ultrasonic Vibration On The Discharge Mechanism And Surface Quality Of Electric Spark Deposition

As a kind of surface machining technology and remanufacturing technology,Electric-Spark Deposition technology can deposit a layer of special material on the surface of the substrate to repair the surface defects of mechanical parts.The discharge mechanism and mass transition mechanism of the technology are complex.The contact state between the electrode and the substrate directly affects the quality and production efficiency of the deposition layer.In this paper,the influence of ultrasonic vibration on the mechanism and surface quality of Electric-Spark Deposition discharge is studied,which provides experimental guidance and theoretical basis for the technology of Electric-Spark Deposition,is conducive to the automatic application of the technology,and is of great significance for improving the surface quality of Electric-Spark DepositionIn this paper,the experiments of Electric-Spark Deposition discharge mechanism under different electrode motion forms are carried out,and the experiments of Electric-Spark Deposition under different ultrasonic amplitudes and different contact forces are carried out.Based on the voltage and current waveform of pulse discharge,the surface morphology and deposition efficiency of deposited overlay and electrode,the discharge mechanism and material transfer mechanism in the process of Electric-Spark Deposition are analyzed.The specific conclusions are as follows:The movement of the electrode directly affects the contact state between the electrode and the substrate,such as the contact gap,contact area and contact resistance,thus affecting the discharge type,discharge current and deposition efficiency.The movement mode between the rotating electrode and the substrate is tangential rotation,and the gap at the contact point changes little,and there is only one mixed discharge type.The movement mode between the electrode and the substrate is up and down ultrasonic vibration.The gap at the contact point changes in a wide range and fast speed,resulting in a variety of mixed discharge types.Under the same discharge parameters,the short-circuit discharge current and gap discharge current of rotating electrode are larger than those of ult rasonic vibration electrode,and the spark and splash are larger,and the depositi on efficiency is lower than that of ultrasonic vibration electrode.The change of ultrasonic amplitude changes the gap between ultrasonic elec trode and substrate.With the increase of amplitude,the number of short-circuit discharge decreases,the number of mixed discharge increases,the spark generat ed becomes larger,and the arc pit of deposition point increases;when the ampl itude of ultrasonic wave is small and large,the transfer coefficient of EDM dep osition is small;the short-circuit discharge time decreases with the increase of ultrasonic amplitude,and the gap discharge time increases with the increase of ultrasonic amplitude.The change of contact force changes the contact state between electrode and substrate.With the increase of contact force,the number of short-circuit disch arge increases,the total short-circuit time increases,the number of mixed discharge and gap discharge decreases,the total gap discharge time decreases,and the sparks and deposition points become smaller.When the contact force is 1n,the mass transferred from the electrode to the substrate is the largest,and the de position efficiency reaches the maximum.