Electrical Discharge Machining Characteristics and Curved-hole Machining of Titanium Alloy Using Suspended Ball Electrode

Abstract

EDM characteristics for titanium alloy workpiece using a copper-tungsten ball electrode with 7.0 mm in diameter were experimentally investigated. While drilling titanium alloy using a suspended ball electrode, the workpiece needs to be vibrated using a vibrator for stable machining performance. Under almost EDM conditions, the removal rate using the suspended ball electrode with workpiece vibration was significantly higher than that using a rod electrode of identical diameter. Furthermore, the electrode wear rate using the suspended ball electrode was lower than that using the rod electrode. Titanium carbide was formed on the machined workpiece surface using the rod electrode. However, the surface using the suspended ball electrode did not form such phase. Additionally, the possibility to machine a curved hole in the titanium alloy using the suspended ball electrode was investigated. The results indicated that curved holes with various angles such as 15°, 30°, and 45° could be machined successfully by tilting the workpiece.