Mathematical modelling and comparative study of the machining characteristics in ultrasonic-assisted electrical discharge machining of cemented tungsten carbide (WC—10%Co)

Abstract

The phenomena occurring between the electrodes in electrical discharge machining (EDM) are still not fully understood. Poor quantitative knowledge of the sources of variability affecting this process hinders the identification of its natural tolerance limits. This paper presents a systematic methodology for developing statistical models to show the relationship between important machining performance data (material removal rate (MRR), tool wear ratio (TWR), and surface roughness R_a) and the input machining parameters (pulse current and pulse-on time) in the EDM and ultrasonic-assisted EDM (US/EDM) of tungsten carbide. The models obtained were used to analyse the effects of input parameters on machining performance. A comparative study was conducted to determine the influence of ultrasonic vibration of the tool on machining performance. The results show that the MRR is significantly increased in ultrasonic-assisted EDM of cemented tungsten carbide (WC—10%Co), especially in finishing modes, and can be up to four times greater than that of conventional EDM. The TWR and R_a values are also increased slightly in US/EDM. The mathematical models presented can be used for optimization of the machining parameters.