Abstract
Self-sharpening phenomena of thin tungsten electrodes in single, high current discharge have been studied by a stroboscopic imaging technique using a fast pulse laser. The diameter of sharpened electrodes depends on discharge duration even though the total discharge energy is kept constant. Effects of four types of machining atmosphere are examined: discharge in working-oil, discharge with working-oil film, discharge in argon gas and discharge in air. The optimal discharge conditions for self-sharpening vary with machining atmosphere. The self-sharpening in argon and air are found to be induced by discharge with higher current.
