Research on Maintaining Voltage of Spark Discharge in EDM

Currently there is no unified understanding about formation of maintaining voltage of spark discharge in electrical discharge machining (EDM), frequency and amplitude of high-frequency components of maintaining voltage and the relationship between high-frequency components of maintaining voltage and parameters of pulse power. Spark discharge self-sustaining conditions, volt-ampere characteristics of discharge gap under transistor resistor pulse power, transistor inductor pulse power and resistor-capacitor (RC) pulse power are analyzed respectively. Spark discharge gap equivalent circuit models of transistor resistor pulse power, transistor inductor pulse power and RC pulse power are established respectively. It also analyzes characteristics between spark discharge gap voltage and output voltage of pulse power under three modes of pulse power, which theoretically proves that there exists maintaining voltage of spark discharge in the process of transistor resistor pulse power and transistor inductor pulse power, while does not exist in the process of the RC pulse power. It also reveals the influence of variation loop structure of pulse power on maintaining voltage of spark discharge.