EXPERIMENTAL ANALYSIS AND OPTIMIZATION OF DRILLING OF GLASS FIBER REINFORCED PLASTICS COMPOSITES USING MADM METHODOLOGY: UTILITY CONCEPT

Composite materials like glass fiber reinforced plastics (GFRP) are immensely utilized in aircraft, automobiles, and several other industries. So, drilling is one of the important manufacturing processes for assembly, and hence care should be taken in order to get damage-free holes. In our research work, we have attempted to find out the impact of a few variables like spindle speed (Ss), feed rate (F,), and drill diameter (Dd) on the output attributes namely thrust force (Tf), torque (Tq), delamination factor (Df), and circularity of holes (Ch) at both entrances and exit. To reduce the number of experiments we used Taguchi L9 68orthogonal array and conducted experiments as per the design of experiment (DoE) approach and obtained thrust force and torque using a dynamometer and then found out Df and circularity at both entry and exit. To find out optimum parametric setting so as to get minimum Df and maximum circularity at both entry and exit we used utility concept and then found out the analysis of variance (ANOVA) and main plots for signal-to-noise (S/N) ratios for overall utility value. The optimum results obtained were being confirmed by doing a confirmation test using the optimum parameters. So, for minimum delamination and higher circularity of holes higher spindle speed and low feed rates and Dd must be used. It was also found out that the damage of holes is more at the exit than at the entry. The same experiment can also be performed on carbon fiber reinforced plastics (CFRP) using other cutting parameters namely point angle, material thickness, etc.