Understanding Dry-WEDM Phenomena Through Periodic Oscillation of Discharge Gap

This paper describes the influence of oscillation of gap length on gap phenomena in dry-WEDM. Dry-WEDM was found to have the problem that lower material removal rate than conventional WEDM because of frequent occurrence of short circuiting resulting from the 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) Fluctuation of total discharge frequency corresponding to the change in gap length is larger in dry-WEDM than that in conventional WEDM because of the narrower gap length in dry-WEDM. 2) Since the short circuiting rate is high in dry-WEDM, the normal discharge frequency is one third of conventional WEDM.