Effect of cutter geometry on machining induced damage in orthogonal cutting of UD polymer composites: FE study

This article presents a finite-element analysis (FEA) based study to understand the influence of cutting parameters (rake angle, relief angle and cutter edge radius) on the machining-induced damage of unidirectional (UD) composites. Carbon/epoxy (CFRP) and glass/epoxy (GFRP) composites are considered. Onset of damage in composites is modelled using a combination of maximum stress and Puck's fracture criteria, while a novel damage propagation algorithm is proposed to account for the post-damage material softening behaviour. A spring-back phenomenon (partial elastic recovery of workpiece material after tool passed a cutting surface) often observed in composites machining, is considered in the FE model to allow a better prediction of the thrust force and induced damage. A validated FE model predicts that with increasing relief angle, the extent of sub-surface damage is reduced. Rake angle or tool edge radius are not found to have a great influence on the induced damage. A large dependence is observed between the fibre angle and the induced damage, as the severity of damage increase when fibre orientations varies from 30 degrees to 90 degrees.