Enhancing hole quality in natural fiber composites: A hybrid PSI-TOPSIS approach for drilling optimization

Natural fiber-reinforced composites (NFRCs) are increasingly used in industries like automotive and aerospace due to their eco-friendliness and lightweight properties. However, drilling NFRCs poses challenges such as delamination, poor circularity, and cylindricity, which compromise structural integrity. This study addresses these issues by optimizing drilling parameters (spindle speed, feed rate, and drill material) using a hybrid multi-criteria decision-making (MCDM) approach. The preference selection index (PSI) and technique for order preference by similarity to ideal solution (TOPSIS) methods were employed to balance conflicting objectives (minimizing delamination while improving circularity and cylindricity), with ANOVA validating the significance of parameters. Results identified the optimal combination as HSS SUPER drill, 560 rpm spindle speed, and 40 mm/min feed rate, achieving minimal delamination and superior geometric accuracy. The study demonstrates that feed rate is the most statistically significant factor ( p < 0.05), while PSI and TOPSIS rankings showed strong agreement, reinforcing the robustness of the methodology. This work provides a practical framework for multi-objective optimization in composite machining, enhancing both quality and efficiency.