The machining behavior of polymers is substantially different from metal and their alloys due to non-homogeneity and anisotropy. This article describes a hybrid optimization method during machining (milling) of epoxy nanocomposites reinforced by graphene oxide/carbon fiber (G/CF). The milling experimentation was staged according to the L-9 orthogonal array of the Taguchi theory. The control of process constraints, namely, cutting speed (V-c), feed (F), depth of cut (D), and G weight % (G) have been appraised to acquired the desired machining response such as material removal rate (MRR), cutting force (F-e), and surface roughness (R-0). Grey-coupled principal component analysis (grey-PCA) effectively tackled the response priority weight during aggregation of conflicting responses. The optimal condition secured by the grey-PCA module are found as V-c = 25.12 m/min, F = 240 mm/min, D = 0.5 mm, and G = 1 %. The supplement of graphene enhances the machining characteristics of the nanocomposites, which in turn, minimizes the damages that occur during the milling process. Scanning electron microscopy (SEM) analysis was conducted for microstructure investigation of the machined component. The findings of confirmatory experiments show good agreement with the actual ones. The preferred solution values of grey-PCA are observed as 1.027, which confirms the proposed technique's higher practicability.
