Mediating compositional machining difference of UD-CFRP in orthogonal cutting by epoxy coating

The intrinsically different mechanical properties between fiber and matrix result into heterogeneous deformation behavior of unidirectional carbon fiber reinforced polymer (UD-CFRP) composites under mechanical loading. And how to minimize even eliminate the compositional machining difference is central for enhancing the machinability of UD-CFRP composites. In the present work, we propose a novel cutting strategy of applying an epoxy coating onto the pre-machined surface, i.e., epoxy coating cutting (ECC), for mediating the compositional machining difference accompanied with promoted machinability of UD-CFRP composites. Experimental results of both ECC and conventional cutting (CC) illustrate the alternation of cutting force, chip formation and machined surface quality by applying epoxy coating. Corresponding micromechanical finite element simulations of ECC reveal that the introduced restraining effect by epoxy coating is effective in prolonging the failure resistance of matrix, and thus minimizing the machining difference between fiber and matrix. The dependence of the mediating effect of epoxy coating on coating thickness is further evaluated by numerical simulations and corresponding experiments. Current findings provide novel insights and a practical guidance for rationally mediating the compositional machining difference of CFRP composites by employing the ECC strategy.