JPS5741131A - Discharge machining process - Google Patents

Abstract

PURPOSE:To get it finished to be a finished plane which is smooth, glossy, and exceedingly small in its roughness in such a way that a proper machining gap is formed between an electrode and a work, and discharge machining is done by means of applying a unit pulse group which has long pulse width and short quiescent time. CONSTITUTION:A gap between an electrode 4 and a work 5 is formed into a proper machining gap 11 which permits discharge, and does not entirely remove the roughness of the work 5, and the electrode 4 is stopped. Discharge machining is done by means of generating a unit pulse group which has the pulse width ON in the long machining unit and short interval OFF through a transistor circuit. In other words, the electrode 4 is set to positive, the work 5 set to negative in their polarities, pulse waveform voltage is applied to the gap 11, discharge column 8 is generated at the tips of the roughness 1, so that the tip parts are evaporated for a short time, and their dissolved parts 9 are formed. With the lapse of time, the discharge column 8 grows bigger, current density is decreased, and the dissolved parts are increased. Here, when current is turned off, the surface of the work 5 is turned out to be a smoothly finished roughness 3, discharge scrapes 10 are adhered thereon to be protective film, and when electric discharge is applied thereon, the roughness 3 can be finished.