INVESTIGATION OF WIRE MOVEMENT IN FINE WIRE EDM BY HIGH-SPEED OBSERVATION

In the wire EDM using a thin wire electrode, the reduction of wire vibration is important to achieve a high-precision machining, since the large amplitude of wire vibration leads to large kerf width, low shape accuracy, rough machined surface, low cutting speed and high risk of wire breakage. In this study, the movements of thin wire electrode during the process were directly observed by using a high-speed video camera in order to clarify the wire movement in fine wire EDM. The effects of machining conditions on the wire movement in the direction perpendicular to the machining direction were experimentally investigated. The results showed that the wire vibration amplitude in fine fire EDM increased with the wire running speed and flow rate of jet flushing but decreased with the wire tension. Also, the wire vibration during the process includes various frequency vibrations with 1st order string vibration. Furthermore, the wire vibration frequency increased not only with the wire tension but also the discharge pulse frequency.