LINEAR INCREMENTAL ELECTRODE OVERCUT INVESTIGATIONS IN EDM USING TAGUCHI TECHNIQUES

Dies and moulds are very important tools to prepare components on the large production scale. The present trend is to use light, slim and compact products, thereby maintaining the dimensional accuracy is prime concern. Electrical discharge machining (EDM) has high capability to generate accurate cavities in dies and moulds with close tolerances. Sparking takes place along the edges of electrode in EDM, resulting in dimensional deviations as linear overcut. Lower linear overcut is preferred along surface profiles, for higher dimensional accuracies. In machining as the profile design changes, linear overcut also vary in particular direction. Therefore in this paper, investigations of linear incremental electrode overcut (OCL) are carried out with other machining parameters such as peak discharge current, pulse on time and spark gap voltage. Taguchi orthogonal array (L16) and analysis of variance (ANOVA) is implemented. It is observed that, current intensity and variation in electrode length (EL) are the major factor affecting linear overcut. The coefficient of correlation (R2 value) is obtained as 94.73%, which indicates good prediction capability for linear overcut response.