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为了快速有效地提高气中电火花线切割加工Cr12MoV模具钢的表面质量,通过有限元法计算并分析了单脉冲气中火花放电条件下工件的温度场分布规律,获得了移动热源作用下工件表面电蚀坑形貌为半双椭球形,这与理想条件下电蚀坑形貌为半球形不同,进而探讨了移动热源作用下不同脉冲宽度对工件表面电蚀坑几何形貌的影响,并与试验结果进行了对比分析。结果表明,修正后电蚀坑深度与工件表面最大粗糙度变化趋势基本相同且数值非常接近,并得出修正前后电蚀坑的长度、宽度及深度随着脉冲宽度的增加不断增大的规律,然而电蚀坑尺寸增加使得电蚀坑体积不断增大,从而提高了气中电火花线切割加工效率,但降低了工件的表面质量。
In order to improve the surface quality of Cr12MoV die steel rapidly and effectively in gas, the distribution law of the temperature field of the workpiece under the condition of spark discharge in single pulse gas was calculated and analyzed by finite element method. The surface of the workpiece under moving heat source was obtained. The morphology of the cavitation pits is semi-double ellipsoid, which is different from the hemispherical shape of the cavitation pits under the ideal conditions. Then the influence of different pulse widths on the electrical erosion pits on the workpiece surface is discussed. The results of a comparative analysis. The results show that the trend of electric pits depth and the maximum roughness of workpiece surface are basically the same and the values are very close to each other, and the law of the length, width and depth of the electric pits before and after the correction increases with the increase of the pulse width. However, the size of the erosion pits increases the volume of the erosion pits, which improves the machining efficiency of the WEDM in the gas, but reduces the surface quality of the workpiece.