Study On The Mechanism And Finite Elements Simulation On Single Pulse Discharge On Gas Dielectric

The research of this dissertation mainly focus on the numerical solutions to the temperature for single pulse discharge based on gas dielectric. The EDM based on gas is a green processing technology, so it is valued by researchers at home and abroad on the field of EDM, and it is one of the research focus on EDM.Study the mechanism of EDM in gas. The results indicate that the discharging process during EDM in gas initially comes from Townsend breakdown process and then changes to streaming breakdown process. The discharging channel during EDM in gas expands more quickly than it does during conventional EDM. The removal of the machining debris during EDM in gas is concurrent results of the thermal expansion, the fluid of compressed gas, magnetic fluid dynamic force, while the thermal stress removal plays a dominant role in machining the hard-brittle material.Do numerous single pulse discharge experiments in gas. The following conclusions can be drawn from numerous single pulse discharge experiments. The single pulse discharge crater of the workpiece on the condition of the positive polarity is bigger than that on the condition of the negative polarity. The single pulse discharge crater of the workpiece is bigger than that of the tool electrode when the tool electrode is cathode and the workpiece is anode. The crater produced by single pulse discharge in the compressed air is bigger than that produced in the air and its form changes according to the fluid of the compressed air. The volume of the single pulse discharge crater increases as the pulse energy strengthens.The physical model of the single pulse discharge in gas was built according to the thermo-physical procedure. The formula of distributed surface flux was deduced by calculating the conversion and distribution of the discharging energy. The mathematical model of the single pulse discharge in gas was built by analyzing the boundary conditions for thermal calculating.Mathematical model of the single pulse discharge in gas can be calculated through FEM (finite element method) software ABAQUS. The thermal load model changing over time and coordinates is achieved by using subroutine DFLUX. The results of the FEM analysis have verified the feasibility of the mathematical model of EDM in gas.