Influence of dielectric flushing conditions during WEDM of TiNiCu shape memory alloys

In this study, the effect of dielectric flushing pressure and direction on the machining responses of wire electrodischarge machining (WEDM) was investigated. Vacuum-melted titanium–nickel–copper (TiNiCu) shape memory alloy Ti₅₀Ni₂₅Cu₂₅, homogenized at 500°C, was used as the workpiece material. The flushing pressure was varied from 0·5 to 1·5 kg/cm² along with pulse-on time (T _on), pulse-off time (T _off), servo voltage and wire feed rate for Taguchi’s L₂₇ experiments. Cutting rate (CR) and kerf width were selected as major WEDM responses, and at optimal CR, the effect of the flushing direction on surface characteristics was studied. It was found that the surface morphology depended mainly on process parameter values and was greatly affected by the flushing pressure. Also, the amount of molten and resolidified debris on samples, machined with the upward-direction flow, was much higher compared with that for the downward-direction flow.