Optimization of drilling parameters for Spanish cherry fiber reinforced hybrid composites using Taguchi analysis

Natural fiber-reinforced composites have gained significant attention in engineering applications due to their sustainability, lightweight nature, and mechanical properties. However, machining these materials, particularly drilling, presents challenges such as delamination, fiber pull-out, and surface roughness, which impact component integrity. Limited research exists on optimizing drilling parameters for Spanish cherry fiber-reinforced hybrid composites to minimize machining defects. This study aims to optimize drilling parameters—drill bit diameter, spindle speed, and feed rate—using the Taguchi L27 approach to enhance machining performance. The composite was fabricated using Spanish cherry fiber, vetiver fiber, and coir pith in a polyester resin matrix through compression molding. Experimental trials analyzed the effects of process parameters on thrust force (TF) and surface roughness (SR), supported by ANOVA and regression analysis. Results indicate that spindle speed has a significant influence on TF and SR, followed by drill bit diameter and feed rate. The optimal setting (8 mm drill bit, 1480 rpm spindle speed, 160 mm/min feed rate) achieved minimal TF (3.82 kgf) and SR (8.76 µm). Water absorption increased with exposure time, with a maximum rate of 7.58% at 192 hours. These findings provide insights for improving composite machining and enhancing structural integrity. Future research should explore the effects of tool wear and alternative machining strategies.