Comprehensive Review of Strategies to Mitigate Delamination and Uncut Fibers in CFRP Drilling

This study aimed to investigate defect mitigation strategies in advanced manufacturing, with a specific emphasis on drilling operations involving composite fiber-reinforced materials. During drilling, critical defects such as peel-up, push-out, delamination, and uncut fibers frequently can occur, adversely impacting product quality and assembly precision. Among these, uncut fibers are identified as the primary focus of this review, given their prevalence around the circumference of the hole’s bottom ply and their detrimental effects on structural integrity. While delamination and related defects are discussed as interconnected phenomena, this review prioritizes the mechanisms, causes, and suppression techniques specifically targeting uncut fiber formation. This review presents a detailed analysis of approaches including tool geometry optimization, bottom-ply support, and advanced monitoring techniques. By synthesizing recent advancements and comparative evaluations, this review aims to provide a consolidated understanding of how uncut fiber defects can be effectively minimized to improve drilling quality and manufacturing efficiency in composite material applications.