Enhanced drilling performance in hybrid bio polymer composites with various coated drill bits

Abstract

This study examines the drilling performance of multi-layered biofiber-reinforced epoxy composites, specifically focusing on hybrid plain woven fabric structures. The analysis considers spindle speed, feed rate, and three tungsten carbide-coated tools to evaluate the quality of drilled holes. Experiments, structured using Taguchi’s L₉ orthogonal array, involve drilling into composites reinforced with hybrid inter and intra-woven jute, white flax, and brown flax fibers comingled with 2 wt% short coir fibers. Performance is linked to coating hardness and the interaction between the tool and composite interface, with parameters like delamination, surface roughness, and circularity error being measured and correlated to drilling conditions. Findings reveal that TiN-coated tools reduce delamination by 16.47% at the front and 13.95% at the back of the hole, and surface roughness by 42.85%. However, TiCrN-coated tools achieve a 28.10% reduction in circularity error. Statistical significance and the contribution of each parameter are assessed using ANOVA, with regression models showing the best fit and optimal predictive accuracy. The 9th hole was identified as the setting with optimal parameters, significantly improving hole quality due to the coatings used.