Relationship between electrode diameter and wear ratio in scanning electrical discharge machining

Abstract

In this study, we propose a new micropin forming method in which the forming plate can be stationary while the rotating electrode moves towards the forming plate. As the processing area in this method is large, a higher removal rate is possible compared with the WEDG micropin forming method. Forming by this method is done easily by a micropin with a diameter less than 50 μm under low electrical discharge conditions. In this study, the aim was to obtain the desired electrode diameter by means of scanning electrical discharge machining. The electrode diameter narrowed rapidly with increasing machining time, and it was difficult to control the micropin diameter by controlling only the machining time. Therefore, the micropin forming was performed by controlling the indicator scanning length during machining. The results depend highly on the ratio of consumption of the forming plate and electrode. The relationship between the electrode diameter and scanning length—obtained from the experimental values and theoretical ratio from the consumption theory—was investigated. Micropins with a maximum diameter of 150 μm were obtained. The experimental values were found to be in good agreement with the theoretical values. Because the wear ratio was changed by the miniaturization of the electrode, there was a difference bet ween the theoretical and experimental values.