微细电火花加工倒凹坑效应的研究

Study on the Effect of End-Tip Concavity by Micro-EDM

对微细电火花圆柱电极损耗出现倒凹坑效应的影响因素进行研究。通常微细电火花电极损耗稳定后,加工端面为半球形,然而在特定的加工条件下,电极端面呈倒凹形状,微孔底端为山状突起,这种异常损耗会破坏电极形状精度而影响加工零件的尺寸精度。通过改变放电能量与放电间隙流体状态等微细电火花加工工艺参数,对比不同实验条件下电极端面形状损耗的变化情况,经检测,出现倒凹坑效应的微孔底端突起为电极材料沉积。实验研究结果表明:电极熔融沉积是电极损耗倒凹坑效应出现的主要原因。

The influence factors of end-pit concavity effect after the wear of micro-EDM cylindrical electrode are studied. Usually end processing is hemispherical offer electrode wear stable. However, under the specific processing conditions, the electrode face and the bottom of the micro hole are respectively end-tip and projection of the mountain. The abnormal wear will destroy the accuracy of electrode and further affect the accuracy of the parts. By changing micro-EDM process parameters such as the discharge energy and discharge gap fluid state and so on, compare with the wear of the electrode end surface under different experimental conditions, the bottom of the micro hole with End-tip concavity effect is detected as an electrode material deposition. The experimental results show that the electrode melting deposition is the main reason for the end-pit concavity effect offer the wear of the electrode.