The high-speed and medium-speed wire electrical discharge machines which are originally developed in China are playing an important role in mold making. However, the wire electrode wear is a universal problem in the machining process because the wire electrode is used repeatedly. Considering the relative motion between the wire electrode and the workpiece, the heat transfer model of wire electrode under moving heat source was established, and the three-dimensional temperature field of wire electrode was simulated in single pulse discharge by FEM. The results indicated that the size of the melted zone along the wire electrode length direction increased remarkably while the depth size of the melted zone reduced apparently when the wire running speed increased. It can be concluded that the high relative speed between the wire electrode and the workpiece is beneficial to reduce the wire electrode wear in radial direction. Furthermore, when the wire running speed up to a certain value, the discharge column will slide over the wire electrode surface before the wire material reaches its melting point, thus the melting and ablation of the wire electrode material don' t happen, which can almost realize no wire electrode wear.%往复走丝和“中走丝”电火花线切割机床是中国独创的电加工设备,在模具制造等行业发挥着重要作用.由于其电极丝是重复使用的,因此电极丝损耗是普遍存在的问题.在电极丝与工件之间相对运动的情况下,建立了移动热源条件下的电极丝传热模型,通过有限元分析对单脉冲放电条件下电极丝表面温度场进行了三维仿真,发现当走丝速度增加时电极丝熔融区沿电极丝长度方向的尺寸明显加长,但熔融区深度方向尺寸明显减小,从而得出电极丝与工件之间的高速相对运动有利于减少电极丝半径方向损耗的结论.当走丝速度增加到一定值时,可使放电通道在电极丝材料达到熔点之前滑过电极丝表面,因此不会发生电极材料的熔融和蚀除,几乎可实现电极丝的零损耗.
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