The effect of machining parameters on drilling induced delamination of carbon fiber reinforced polymer composite

Delamination is one of the most common defects occur during drilling of carbon fiber reinforced polymer composites. It is an inter-ply failure phenomenon and it has to be minimized to have better quality of drilled holes for structural applications. The current study is conducted to investigate the effect of machining parameters (spindle speed, drill diameter, feed rate and point angle) on delamination while drilling of 60-40 weight % and 55-45 weight % of bi-directional carbon fiber reinforced polymer (BD CFRP) composites with titanium nitride (TiN) coated solid carbide drills. Taguchi L₂₇ orthogonal array is used for determining the experimental results of delamination and the Taguchi methodology is also employed for determining the predicted results of delamination of both BD CFRP composite laminates. The investigation reveals that there is a good concurrence between the experimental and the predicted results of delamination. The main effect plot shows that the drill diameter has a significant effect on delamination as compared to the effect of spindle speed and feed rate. The point angle has an insignificant influence on delamination in drilling of BD CFRP composites. It is evident from the investigation that 45 weight % of resin content of BD CFRP composite gives lesser delamination as compared to the composite containing 40% of resin. Hence, 45-55 weight % of BD CFRP composite laminate can be a better choice for structural applications in industries.