Optimization of Drilling Parameters in Natural Fibers Composite Plates Based on Grey Relational Analysis

This study focuses on optimizing drilling parameters to minimize delamination, circularity error, and cylindricity in natural fiber composites through a comprehensive full factorial Design of Experiments (DoE) combined with Grey Relational Analysis (GRA). The novelty of this work lies in its systematic integration of these methods to evaluate the effects of spindle speed, feed rate, and drill type (HSS, HSS-Co, and Solid Carbide) on hole quality, providing a robust framework for multi-response optimization. Results reveal that feed rate is the most significant factor, with optimal conditions – lower feed rates (0.04 mm/rev) and moderate speeds (1592 rpm) – delivering reduced delamination and improved hole quality. Among the tested drills, Solid Carbide demonstrated superior performance with the lowest delamination and cylindricity errors. This study highlights the potential of systematic parameter optimization to advance eco-friendly composite manufacturing and enhance drilling precision.