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