单脉冲放电蚀除特征及规律研究

单脉冲放电的蚀除特征是放电加工的基本单位,开展单脉冲放电蚀除特征研究对于认识连续放电加工的过程以及放电加工时的电参数选择有着十分重要的意义。首先对单脉冲放电材料蚀除机制进行了介绍;然后基于材料的电—热模型,借助ANSYS软件对能量在材料内部的热传导过程进行了仿真,获得了材料熔融区域的半径随脉宽变化的规律;最后在自主研发的微细电火花加工机床上开展了不同脉宽、不同极性下的单脉冲放电实验研究。实验结果表明:无论极性如何,随脉宽增加,电蚀坑的直径、深度和蚀除体积都增大,但径深比减少;在相同脉宽下,工件接正极时的电蚀坑的直径、深度和蚀除体积比接负极时更大,但径深比更小;极性蚀除比(工件接负极时的放电坑的体积/工件接正极时的放电凹坑的体积)随着脉宽增加呈现减少的趋势。

Research on the Erosion Feature and Rule of Single Electrical Discharge Pulse

The erosion feature of single electrical discharge pulse is the base unit of electrical discharge machining .Research on the erosion feature of single electrical discharge pulse is of great significance on understanding the process of electrical discharge machi -ning and choosing the electrical parameter .Firstly, the material erosion-mechanism of single electrical pulse was introduceed .Second-ly, a simulation about the thermal-conductivity process of energy within the material was carried out based on the electricity -thermo model by using ANSYS , an regular that molten zone radius of the material varies with the pulse width was obtained .Finally, a series of experiments including different pulse width and polarity were carried out in the micro-EDM machine tool which had been developed by Institute of machinery manufacturing technology .The experimental results indicate that no mater what the polarity is , the diameter , depth and erosion-volume of electrical pit will increase while the diameter-depth ratio will decrease with the pulse width increasing;the diameter , depth and erosion-volume of electrical pit are greater when workpiece is used as cathode , while the diameter-depth ratio is smaller in the same pulse width;polarity erosion-ratio of electrical pit will decrease with the pulse width increasing .