Optimization of thrust, torque, entry, and exist delamination factor during drilling of CFRP composites

Among variety of fiber-reinforced polymer (FRP) composites, the carbon fiber-reinforced plastics (CFRP) are found to be highly promising materials for widespread applications in aeronautical and aerospace industries. The delamination is a major problem associated with drilling of fiber-reinforced composite materials, which tends to reduce structural integrity of the said material. The problems in drilling, particularly the heterogeneity and anisotropy of composite materials increase delamination. Therefore, drilling of CFRP composites requires adequate attention toward achieving superior hole quality, surface finish, as well as dimensional accuracy by achieving delamination-free machining. However, drilling process is influenced by several machining parameters like drill speed, drill bit diameter, as well as drill material, feed, etc. Direct and interactive effect of aforesaid process variables influences machining performance in terms of quality of the drilled hole. Therefore, an optimal parameter setting is indeed required. To address these issues, present study aims at evaluating an appropriate drilling parameter setting toward optimization of thrust, torque, entry, and exist delamination factor during drilling of CFRP (epoxy) composites. An integrated multiresponse optimization philosophy combining principal component analysis (PCA), fuzzy inference system (FIS), and Taguchi method has been proposed here. The aforesaid optimization module has been found efficient enough to overcome inherent limitations as well as unrealistic assumptions of existing optimization approaches as documented in literature so far.