A critical review on mechanical micro-drilling of glass and carbon fibre reinforced polymer (GFRP and CFRP) composites

Recent trends in miniaturisation and high-strength fibrous composites encourage the use of mechanical micro-drilling technology of fibre-reinforced polymer composites (FRPs). Although severe expertise has been gained through the past few decades on the machinability of FRPs, this information cannot be directly adapted to the micro-drilling mainly due to the size effect. Therefore, the main aim of the present study is to comprehensively review challenges, recent experience, and future aspects of mechanical micro-drilling of glass and carbon fibre reinforced polymer (GFRP, CFRP) composites. The chip removal mechanisms of micro-drilling of FRPs are reviewed and compared to conventional-sized technologies. Furthermore, the micro-drilling-induced geometrical defects (delamination, burrs, fibre pull-outs etc.) and the cutting energetics are also discussed. Moreover, the future aspects and research directions are highlighted in this growing research area.