Delamination and tool wear in drilling of carbon fabric reinforced epoxy composite laminate

In the present work, drilling experiments were performed on carbon fiber reinforced epoxy composites, fabricated by compression molding. The effect of various process parameters on delamination and tool wear during drilling were investigated. The laminate, after fabrication, was tested to find the elastic modulus, fiber volume fraction and tensile strength. A full factorial experiment with process parameters at three levels each were performed initially to find the optimum cutting condition which was used in the second experiment to compare the performance of four different drill bits with varying geometry. Analysis of delamination and tool wear revealed that the tool with point angle 90°, helix angle 35° was the best tool for drilling carbon fiber reinforced epoxy composites as it resulted in the least delamination and showed no significant tool wear. Tool with point angle 140°, helix angle 30° also performed well while TiAlN coated tool performed poorly due to the erosion of the coating at the cutting edges resulting in increased cutting forces and higher delamination. Delamination and tool wear was observed to be the highest in tool with a point angle of 118°and helix angle 30°.