Numerical study addressing the CER effect on microscopic chip removal mechanisms of CFRPs via the orthogonal cutting

Abstract

Understanding the microscopic mechanisms of fiber fracture and removal plays a vital role in optimizing the cutting process and tool wear progression of carbon fiber reinforced polymers (CFRPs). Cutting edge radius (CER) is a critical parameter determining the surface formation of CFRPs as chip removal takes place by the action of cutting edge. In this study, micro-mechanical finite element (FE) models based on the maximum stress criteria were developed to reveal the influences of CER on fiber removal mechanisms governing the orthogonal cutting of UD-CFRPs. The results show that the CER significantly impacts both the transition of fiber removal modes and subsurface damage formation in CFRP cutting. At the 0° fiber orientation, increasing the CER tends to intensify the compression-induced fracture for fiber layers interacting with the tool. While for 45° and 90° fiber orientations, the key fiber separation mode changes from shear-induced fracture to bending-induced fracture as the CER rises. For the 135° fiber orientation, chip removal faces the greatest difficulty, with significant compressing and squeezing effects occurring, leading to poor fiber breakage and severe subsurface damage. Moreover, a smaller CER benefits the reduction of subsurface damage but increases the risk of edge chipping due to higher stresses concentrating at the cutting edge.