A Contribution on the Modelling of Wire Electrical Discharge Machining of a γ-TiAl Alloy

Wire electrical discharge machining (WEDM) is a manufacturing process suitable for high-precision cutting of complex and irregular shapes through difficult-to-machine electrically conductive components. In recent years, wire EDM has become a key non-traditional machining process, widely used in the aerospace and automotive industry. Although this technology has been broadly investigated, literature is still limited on the use of wire EDM for intermetallic alloys, and the applications on gamma titanium aluminides are rather unexplored. Such materials are attracting considerable interest due to the outstanding combination of properties, and they have proved to be eligible for thermo-mechanically stressed parts of aeroengines. Nevertheless, the poor machinability of gamma titanium aluminides has been reported in conventional (i.e. turning, milling, and drilling) and non-conventional machining, such as ECM. Further, machinability results strictly depend on the chemical composition of the specific alloy. This paper investigates the interactions between common process parameters of WEDM and final quality of the generated surface, through analysis of variance (ANOVA) and regression models based on experimental results. In particular, the paper is focused on the effects of pulse on time, pulse off time, servo-reference voltage, and wire tension on the surface finish during the WEDM of a Ti-48Al-2Cr-2Nb (at. %) γ-TiAl alloy. Results are discussed and compared with reference to the models available in literature.