Nonlinearity and periodicity in machining carbon fiber reinforced polymer

Abstract

In the machining of carbon fiber reinforced polymer (CFRP) materials, the relationship between the cutting forces and uncut chip thickness can be linear or nonlinear, depending on the fiber orientation ranges. In addition, the variation of cutting forces in two consecutive cuts is periodic at a certain fiber orientation of 120 deg and the uncut chip thicknesses of 30μm60μm. It is suggested that the material removal rate changes even for the same uncut chip thickness in consecutive cuts, such as milling and drilling. Through orthogonal experiments for unidirectional CFRP at various fiber orientations and uncut chip thicknesses, this study aims to analyze the observed nonlinearity and periodicity of cutting forces which occur at certain fiber orientation and uncut chip thickness. It is found that both the nonlinearity and periodicity are primarily dependent on the machined surface damage left by the previous cut. This damage state varies with the uncut chip thickness and is influenced by the interaction between the material deformations at the tool rake face and flank face. Thus, the reported findings in the chip formation and cutting force generation reported by this study can guide the tooling and process planning to enhance the machining performance for CFRP.