Multi objective optimization of parameters in EDM of Mirrax steel

Accompanying the technological development and the advancement in the industry, the demand for materials with superior properties such as high strength, hardness and toughness is increasing. This made it difficult or impossible to cut these materials by conventional methods. Electric discharge machining (EDM) is one of the most important unconventional machining methods that have the ability to cut electrically conductive materials regardless of their mechanical properties. In this study, the machinability of Mirrax plastic mold steel was investigated experimentally employing the electrical discharge machining technique, and its machinability was optimized using gray relational analysis. Experiments were carried out using the Taguchi L-27 orthogonal setup, with the electrode type, discharge current, pulse on time, and pulse off time as inputs. The surface roughness was measured, the material removal rate and the electrode wear rate values were calculated. A multi-purpose optimization study was carried out for the outputs. The analysis of variance results defined that the discharge current was the most influential parameter among the machining parameters, whereas the pulse off time was ineffective in the processing of Mirrax plastic mold steel via EDM. The Taguchi based gray relational analysis determined that the GRG value had been improved by 32.24%.