An Investigation on Drilling of Epoxy Composites by Taguchi Method

Effects of process parameters such as rotational speed, feed rate, and drill diameters on the drilling behavior of basalt-epoxy-based composites including 2.5 wt.% Al2O3 particles manufactured by mixing and compression method were investigated by Taguchi's technique. The experimental results showed that the burr height (BH) increased considerably almost linearly with an increase in the drill diameter, while it remained stable with speed and decreased the feed rate slightly. There was an excellent correlation between the control factors and responses, BH of basalt fiber-reinforced plastics (BFRPs) through the Taguchi approach. The model had an adjusted R-2 value of 96.3%. Generally, the inclusion of Al2O3 particles in BFRP increased its cutting force properties. Optimized drilling conditions for the input variables to produce the lowest response of the BH for composites were rotational speed of 560 rpm and feed rate of 0.28 mm/rev and a drill diameter of 4.5 mm. Furthermore, the analysis of variance (ANOVA) indicated that the drill diameter was the most significant control factor affecting the BH. Its percentage contributions (Pc) of rotational speed, feed rate, and drill diameter on the BH were about 0.38%, 1.15%, and 98%, respectively. Furthermore, macrographs of drilled composite surfaces exhibited that fiber fracture and pullout increased with increasing drill diameter, leading to the BH and depth of the deformation zone.