Effect of process parameters on volume and geometrical features of electric discharge machined channels on a cast aa6061-b4C Composite

Abstract

The effect of various input EDM parameters on the volume and dimensional features of channels produced on AA6061-4%B4C composites was studied. The composite material specimens were prepared by liquid melt stirring process. The sinker EDM was used to machine the channels on these composites. Taguchi L-9 (Design of Experiments) was used to plan the EDM experimentation. The ‘I’ (discharge current), ‘T-on’ (pulse-on time), and ‘T-off’ (pulse-off time) were considered as input conditions. Each of these input parameters was varied at three levels. The volume of the channel obtained after EDM was estimated by developing the CAD-based geometric model. In addition to volume, various geometrical features such as taper, overcut, and the difference in depth at the entrance and exit of each channel were considered as output responses. The regression analysis and the ANOVA were performed for all responses. A set of optimum EDM input parameter levels were identified for a maximum of volume and minimum of taper, overcut, and the difference in depth values. Results showed that the volume was found to be maximum at higher ‘I’ and lower ‘T-on’ conditions. It was observed that there is a considerable difference in the taper and overcut values in the entrance and exit portions for the same channel. Both the ‘I’ and the ‘T-on’ were found to be the influencing parameters with decreasing order of their percentage contribution affecting all the output responses. The reasons were discussed in detail for all the conclusions arrived in the present work.