Modelling of machinability parameters of carbon–carbon composite—a response surface approach

This paper reports the experimental investigations on the electric discharge machining of carbon–carbon composite plate using copper electrodes of negative polarity. The relevance of this study is that it establishes empirical relations, as a function of machining variables, relevant to analyse the machinablity of carbon–carbon composite. The machinability parameters (response functions) considered are relative circularity of hole represented by the ratio of standard deviations, overcut, electrode wear rate (EWR) and material removal rate (MRR) while machining variables are pulse current, pulse on time and gap voltage. Experiments are conducted on the basis of Response surface methodology (RSM) technique. Empirical models correlating process variables and their interactions with the said response functions have been established. The models developed reveal that pulse current is the most significant machining parameter on the response functions followed by gap voltage and pulse on time. These models can be used for selecting the values of process variables to get the desired values of the response parameters.