中文摘要：

工具电极损耗对工件的精度有较大影响.从电火花加工实质为热能加工着手,对常温和液氮冷却下工具电极单脉冲放电温度场进行对比、分析,通过传热理论得出常温下和液氮冷却时工具电极表面温度场及其变化曲线.结果表明:脉宽内,液氮冷却可降低放电点最高温度和温升;脉间内,液氮冷却可将放电点温度在极短时间内冷却至初始温度,从而减少因热量累积导致的工具电极损耗.因此,液氮冷却可有效降低工具电极损耗.

英文摘要：

Tool wear obviously affect the accuracy of the workpiece in EDM .Thermal etching is the nature of EDM machining .Simulation comparisons between common and cryogenic cooling EDM were conducted ,from which the temperature fields and temperature curves were obtained . Then ,the simulation were studied and analyzed by using heat transfer theory . The analysis showed that ,after the discharge pulse ,liquid nitrogen could lower the maximum temperature and temperature range around the discharge point ,and after the pulse interval ,the temperature of the discharge point could be cooled to the initial temperature in an extreme short time ,and avoided heat buildup caused by other discharge ,which reduces tool wear caused by heat buildup .Thus , cryogenic cooling has obvious effect to reduce the tool wear in EDM .