Investigating effect of tool geometry on drilling performance of carbon fiber-reinforced polypropylene thermoplastic composite

The current research explores the impact of tool geometry on the drilling performance of carbon fiber-reinforced polypropylene thermoplastic composite. Three distinct tools, namely conventional twist drill (CTD), split point drill (SPD), and brad spur drill (BSD), were used to investigate their geometrical effect on the critical parameters such as drilling temperature (DT), thrust force (TF), exit delamination factor (EDF), and surface roughness (SR). Increasing spindle speed caused the drilling temperature to increase, while increasing the feed rate caused it to decrease. Thrust force increased and decreased in response to increased feed rate and spindle speed, respectively. The exit delamination factor decreased by changing the feed rate from 60 mm/min to 120 mm/min and again started to increase up to 180 mm/min. Surface roughness increased as the feed rate increased from 60 to 120 mm/min and then decreased when the feed rate increased from 120 to 180 mm/min. Drilling with Brad spur tool with a feed rate of 60 mm/min and a spindle speed of 900 rpm provided the optimized result. Compared to the conventional twist drill, the brad spur drill produced 37.72%, 49.53%, 16.67%, and 34.25% less drilling temperature, thrust force, exit delamination factor, and surface roughness, respectively.