Effects of Twist Drill Point Angle on Thrust Force and Delamination Factor in Hybrid Fiber Composites Drilling

Drill point angle of twist drill has a significant effect on thrust force and delamination factor on drilled holes in fiber reinforced polymer (FRP) composites. In this study, three drill point angle of twist drill; 85 degrees, 118 degrees and 135 degrees were used to drill holes in hybrid fiber reinforced polymeric composite (HFRP). HFRP composites were fabricated using vacuum infusion molding (VIM) technique. The test samples were cured at 90 degrees C for two hours. In drilling process various drill point angle and feed rate were employed to investigate the effect of both parameters on thrust force and delamination factor when drilling the HFRP composite. The results showed that small drill point angle and low feed rate can reduce the thrust force leading to the reduction of damage factor at the hole's entrance and exit.