Cutting force modeling in the electrical discharge assisted milling of Ti-6Al-4V in a multi-hybrid energy field based on finite volume method

Previous studies have confirmed that electrical discharge machining assisted milling (EDAM) is an effective method for machining titanium alloys precisely and efficiently. However, there is little research on the precise control of machined surface quality in EDAM through theoretical models. Hence, in this research, a cutting force model of EDAM under a multi-hybrid energy field, including the discharge thermal temperature field (DTTF) and the cutting thermal temperature field (CTTF), was developed. Further, the DTTF was numerically analyzed using the finite volume method (FVM). In particular, through the theoretical derivation of the classical cutting temperature model, classical cutting force model, and Johnson-Cook (J-C) constitutive model, the temperature of the principal shear plane and the shear flow stress under different discharge energies were obtained in this analysis. In particular, the analysis showed that when the capacitance was 100,000 pF, the heat distribution on the workpiece was relatively uniform, and the temperature of the workpiece was the highest among those from the analyses under different capacitances, respectively. Subsequently, the validity of the cutting force model under many aspects was verified by conducting EDAM of Ti-6Al-4 V. Specifically, the experiment was carried out based on the optimal discharge capacitance (100,000 pF) found from the cutting force model and demonstrated that the EDAM, compared to conventional milling (CM), could significantly improve the machined surface quality and reduce tool wear. Hence, the cutting force model provided important theoretical support for parameter selection in EDAM.