Research On Establishment And Simulation Of Teperature Field Model Based On Single Pulse Dry EDM

Electrical discharge machining(EDM) is an indispensable processing method for hard materials. However, because of including many factors, the micro mechanism of the technology has not yet made a breakthrough, which leads to certain limitations of the application of the technology. Computer simulation technology is one of the effective methods to understand the microscopic process of EDM, and the research of EDM simulation is mainly focused on the temperature field simulation. Because the research results of simulation depend on the accuracy of the theoretical model,it is necessary and important to improve the temperature field model and Simulation Research of EDM.In addition, the dry-EDM is considered to be the basis of the traditional EDM.Therefore the research on single pulse discharge and temperature field in gas can not only strengthen the material corrosion mechanism of the dry-EDM, but also expected to have a further understanding of the traditional EDM. The temperature field model in the gas can not completely copy the model of the oil, but it is short of temperature field model in gas now. It is necessary to carry out the single pulse test, which provides the basis for the establishment of the temperature field model in gas. So, based on the experimental results of single pulse in gas and the basic theory of EDM, the temperature field simulation model is established, then doing the temperature field simulation of single pulse dry-EDM.Firstly, Single pulse experiments were carried out under different electric parameters,electrodes and dielectric conditions. The effects of different parameters on the discharge results are obtained by comparing the discharge waveform and the crater morphology,providing the basis of the simulation model of single pulse dry-EDM temperature field.The experiment of different peak current and pulse width provides the basis for the establishment of the discharge channel in gas. The comparison test of different polarity and electrode materials provides the basis for determining the energy distribution coefficient. The comparison experiment of different medium is aimed to analyze the influence of the medium on the morphology and the voltage of the single pulse discharge crater.Secondly, A physical model of EDM is established, and the boundary conditions of the model are determined. Compared with the type of heat source distribution, theGauss heat source model is selected. Then the formula of heat flux density in gas is derived. According to the experimental results under different conditions in air medium,the radius of the plasma channel in the heat flux formula is obtained. According to the experimental results of single pulse and other scholars’ research results, the distribution coefficient of energy in the heat flux formula is determined.Finally, based on the simulation of single pulse electric discharge machining temperature field model, analyze the temperature field distribution and the size of the crater. Analyze the relationship between the temperature field change, the change of the plasma channel and the change of the pit size. For different parameters of the gas in the electrical discharge machining simulation, analyze and explain simulation results.Finally complete the verification experiment.