Drilling fibre reinforced polymer composites (CFRP and GFRP): An analysis of the cutting force of the tilted helical milling process

Abstract

Hole making is one of the most common machining operations in fibrous composites. Holes can be produced using conventional machining technologies. However, in these cases, the size of delamination and burr appearance are often significant mostly due to the relatively large axial cutting forces. The main purpose of this research paper is to optimise and compare tilted helical milling processes in the case of carbon and glass fibre reinforced polymer (CFRP and GFRP) composites. In the scope of this research paper, numerous tilted helical milling experiments were carried out on CFRP and GFRP composites using an uncoated carbide end mill. The influences of the tilting angle and the pitch of the helical tool path on the axial cutting force were analysed and discussed based on experimental results and analytical models. In addition, machining-induced burr and microstructure were analysed using optical-digital and scanning electron microscopy, respectively. Experimental results show that both cutting force and burr are significantly influenced by pitch and tilting angle. Furthermore, the maximisation of the tilting angle is recommended in any of the cases examined in the scope of our study.