Study on the movement of wire electrode during fine wire electrical discharge machining process

Wire movements and vibrations are one of the most important phenomena of wire electrical discharge machining (EDM) process. Unstable wire electrode behavior and large wire vibration amplitude during the process cause wire breakage, low shape accuracy and large machined surface roughness. In this study, direct observation using high-speed camera investigated the movements of tungsten wire electrode during fine wire EDM process. The results showed that the vibration amplitude and frequency depended mainly on the wire tension, and the amplitude direction. The amplitude in the direction parallel to the machining direction was a little larger than that in the perpendicular one. In addition, the backward deflection of wire could be confirmed even in fine wire EDM. Also, the wire vibration mode was analyzed, and it could be varied with the machining position of the thin workpiece, which possibly led to smaller wire amplitude. Furthermore the amplitude envelope of wire electrode during the process was clarified.