Wire electric discharge machining (WEDM) is a widely accepted non-traditional material removal process for manufacturing of components with intricate shapes. Wire electric discharge machining is assessed on basic of metal removal rate (MRR) and surface roughness (Ra). WEDM is extensively used in machining of conductive materials where precision is of major factor. The process output is affected by large number of input variables. Experimentation has been done using Taguchi's L9 orthogonal array. Each experiment was conducted under different combinations of pulse on time, pulse off time and peak current. The optimum machining parameter combination was obtained by using the analysis of signal to noise (S/N) ratio, analysis of means and analysis of variance (ANOVA). Further, the level of importance of the machining parameters on copper alloys was determined by using ANOVA. The study shows that the Taguchi's method is suitable to solve the stated problem with minimum number of trails. © 2019 Elsevier Ltd. All rights reserved.