微电火花加工中探针与工件中铁元素作用机理研究

Interaction between probe and iron atoms of workpiece in micro electro discharge machining

以加工工件中铁原子为基组构成基本模型,通过理论计算和模拟研究了铁元素在分别外加面电极和体电极情况下,整个系统的电子传输过程与电子态密度的分布。结果显示在外加体电极时,相比于加面电极时的情况,其电子穿过体系的概率更大,有利于整个系统的电子传输,对电火花加工更有利。另外还得出了两个传输系统的能级和能隙,能量对比显示,在外加体电极时,分子失去电子的能力比加面电极强,且更加容易发生跃迁,整个体系的加工性更好。考虑实际加工过程,对电极和工件间距离变化时系统的电子传输和态密度的变化进行了研究,结果显示,钨面电极在距离为0.48nm时,电火花加工处于截止状态,而钨体电极则是在距离为0.58nm时,电火花加工截止。

The basic model based on iron atoms of the workpiece is built, Oy meoretlcai caicutaLLuu miu simulation technology, electronic transmission and density of state of the two different systems that are plane and three-dimension probe are researched. The result shows that the electronic transmission probability with three-dimension electrode is greater than plane electrode and is beneficial to micro machining. The highest occupied molecular orbital and the lowest unoccupied orbital as well as energy gap are also calculated, which shows that the ability of the electronic transmission in the system with three-dimension electrode is higher and better machining than that with the plane probe. Furthermore, the change of the electronic transmission and the density of state with different distances between the iron atoms and the probe is obtained. The result shows that the electro discharge machining with plane electrode stops since the electrons can not transport when the distance is greater than 0.48 nm, and when the distance is 0. 58 nm, the same situation appears in the electro discharge machining with three-dimension electrode.