Delamination assessment in drilling basalt/carbon fiber reinforced epoxy composite material

tThe present work aims at assessing the delamination damage occurring in a hybrid compos-ite material during the drilling process. The hybrid composite selected for work comprisesof basalt and carbon fibers as reinforcements and epoxy as the matrix. Process parametersquantified by speed, feed, and drill size are the selected input independent variables. Theresponse variable, delamination factor (Fd), for each experimental combination, is deter-mined using the simple Chen's one-dimensional equation. Taguchi's L27 orthogonal array(OA)-based experimental design with the 'smaller-the-better' approach forms the base forexperimental runs and optimization in the present work. ANOVA is applied in the presentwork to investigate the significance of the linear, squared, and interaction effect of speed,feed, and drill diameter on the delamination damage. Besides, the regression predictionmodel is developed and validated through a set of confirmation experiments. The optimumprocess parameters in the drilling of hybrid composite concerning delamination are drilldiameter (D) of 6 mm, speed (N) of 1250 rpm and feed rate (f) of 50 mm/min. The regres-sion model developed shows a high degree of fitness with both R-sq and R-sq (adj) valuesabove 80%. The results of confirmation experiments show that the predicted model is highlyadequate and there exists only an average prediction error of approximately 2%.