ギャップ長変動による気中ワイヤ放電加工の極間現象の解明
2004 年 38 巻 89 号 p. 18-26
詳細
2004 年 38 巻 89 号 p. 18-26
This paper describes the influence of oscillation of the gap length on gap phenomena in dry-WEDM. Dry-WEDM was found to have some problems such as a higher susceptibility to wire breakage due to the localization of discharge spots and a lower material removal rate than conventional WEDM, because of the frequent occurrence of short circuiting due to a narrower discharge gap length Since the material removal rate depends on the normal discharge frequency, the gap length was altered periodically using a piezoelectric actuator to obtain the relation between the gap length and normal discharge frequency. It was found that 1) The fluctuation of total discharge frequency corresponding to the change in gap length is larger in the dry method than in the conventional method because of the narrower gap length in dry-WEDM. 2) Hysteresis was observed in the change in total discharge frequency, and the total discharge frequency was higher during the period of gap widening compared with the period of gap narrowing. 3) Since the short circuiting rate is high in dry-WEDM, the normal discharge frequency is one third that in conventional WEDM. 4) The ratio of the normal discharge frequency in dry-WEDM to that in conventional WEDM is higher than the ratio of the material removal rates. Hence, it is considered that the total volume of debris evacuated from the gap per one pulse discharge in the dry method is smaller than that in the conventional method.
