Experimental and numerical analysis of thrust force and torque during drilling of bi-directional graphene reinforced GF/epoxy polymer nano composite

In recent times, multi-nanoparticle reinforced polymer composites are extensively used due to its improved properties. Drilling is a highly challenging machining operation to ensure hole quality in FRP composites because of their heterogeneity, anisotropy and brittleness. Delamination is regarded as the most serious drilling defect among all the machining defects and is directly related to the thrust force. Thus, accurate estimation of the thrust force and torque are required during drilling operations of GFRPNCs. In this context, the thrust force and torque values were recorded experimentally and compared with predicted values obtained from a analytical model based on drilling mechanics and drill geometry. Two different layups, (0/90)S (neat) and (0/90 ± 45)2S (reinforced with graphene) and three drill types such as uncoated and coated (TiAlN, TiN) solid carbide drill were used in this investigation. For (0/90)S layup, the thrust force obtained by the uncoated solid carbide drills was found 38 to 53% when compared with TiAlNcoated drill and between 57% and 92% higher when compared with TiNcoated drill for different feed rates considered for this experiment. Similarly, for (0/90 ± 45)2S layup, it was between 51–63% higher than that of TiAlNcoated drill and 55–84% higher than that of TiNcoated drill. It is found that the thrust force values decreases by almost 9.41%, 13.2% and 8.21% in case of modified graphene reinforced laminate when drilling with uncoated, TiAlNcoated, TiNcoated carbide drills respectively. Additionally, The findings revealed that the thrust force and torque model considered for drilling are consistent with the experimental measurements with an average error of ∼6.18% and ∼5.30% for(0/90)S (neat) layup and (0/90 ± 45)2S layup respectively.