Mechanisms and evaluation of the influence of cutting temperature on the damage of CFRP by helical milling

The quality of holes machined in carbon fibre reinforced plastic is vital to the strength of CFRP/Ti stacks. In this study, the influence of cutting temperature upon hole damage of CFRP in CFRP/Ti stacks under helical milling was compared with and without the presence of an underlying Ti. The cutting forces, exit quality, wall surface and subsurface quality of CFRP hole were analysed. And proposing a method to evaluate subsurface damage, and combined with the tensile test to study the effect of subsurface damage on the mechanical properties of CFRP. The results suggest that titanium alloy slightly exerts an effect on the cutting force and exit and wall mass of CFRP holes, yet dramatically affects their subsurface mass. High cutting temperatures may degrade the performance of the CFRP resin matrix, which may cause further subsurface damage closest to the hole exit. The proposed method is used to evaluate subsurface damage. It was most serious in the fibre layer near the hole exit and gradually decreased with distance from the exit. The results of this study will help improve the machining quality of CFRP/Ti stacks.