“…For analyzing the effects of electrical discharge machining process parameters on performance factors, as well as developing empirical models, the RSM has been the most widely used technique in recent years [ 30 ]. It includes a set of mathematical and experimental techniques that require sufficient experimental data to analyze the problem and develop mathematical models that consider the dependencies of several input variables and the resulting factors [ 27 , 31 , 32 ]. This feature is important because the EDM process usually analyses the influence of several input factors (usually three, four or more), which can include: open circuit voltage, pulse-on-time, pulse-off-time, discharge current, duty cycle, working-fluid flushing pressure, electrode, electrode polarity, electrode material, and initial interelectrode gap [ 20 ].…”