Effect of ultrasonic-assisted EDM on the surface integrity of cemented tungsten carbide (WC-Co)

This paper studies the effects of tool electrode ultrasonic vibration on some surface integrity properties of cemented tungsten carbide (WC-10%Co) in the electrical discharge machining (EDM) process. Surface integrity concerns surface alterations associated with a manufacturing process, including surface topography, surface metallurgy, and changes of the mechanical and physical properties of the material as well as residual stresses. Scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) capabilities, optical microscopy, micro-hardness testing and white light interferometric microscopywere employed to study the surface integrity. This paper studies the topography of the machined surface, the size and amount of cracks on the surface layer, hardness variation in the depth and the composition of the defective layer, when machining with and without ultrasonic vibration of the copper electrode under different machining conditions. SEM, micro-hardness testing results together with surface topography investigation showed ultrasonic-assisted EDM applicability in improving surface integrity.