Research On EDM Technology With Graphite Electrode

Because of the advantages such as lower wear ratio, rapid machining speed, high heat-resistant and machining precision, graphite electrode is a kind of perfect electrode material in the EDM process of die and mould. In order to improve its use in the industry, it is valuable and important to research machining technology of graphite electrode for EDM.In this thesis, parameters optimized selection model of graphite electrode for EDM is established based on the research of EDM characteristics of graphite electrode and adaptability of machining technology to different EDM machine tools.Effects of electrode polarity, pulse duration, pulse interval, open-circuit voltage, peak current, grain size of graphite electrode and workpiece material on EDM characteristics of graphite electrode were studied through a lot of experiments and analysis. EDM characteristics of graphite electrode were measured on four EDM machine tools in order to analyze adaptability of machining technology to EDM machine tools. EDM machining technology model with graphite electrode established by BP neural network were carried out.The results indicate that effects of pulse duration and peak current on EDM characteristics, including the electrode wear, material removal rate and surface roughness, are significant. There are an optimum pulse-off time and open-circuit voltage in this experiment. Grain size of graphite, workpiece material and it was also found in this thesis that EDM machine tools affect the results of EDM characteristics. It was proved that that EDM machining technology model with graphite electrode established by BP neural network can effectively predict machining effect, and really reflect machining technology rule of machine tools. The mean predicted errors were 3.62%, 2%, 15.7% for material removal rate, surface roughness and electrode wear, respectively,...