Study on the cutting force responses in machining multiscale carbon nanotube/carbon fiber reinforced polymer composites

Orthogonal cutting experiments were performed on the multiscale carbon nanotube/carbon fiber (CNT/CF) reinforced polymer composites with various wt. fractions of multiwalled CNTs (MWCNTs) filled in the epoxy to investigate the machinability of the material. In particular, the characteristics of the cutting force were studied as a response to the CNT content, the fiber orientation and the depth of cut. Results show that the effect of the CNT content on the principle cutting force in 135° orientation shows a different pattern than that in the other orientations. The mechanism was studied with an analytical mode proposed for the chip formation process. The depth of cut has a more significant effect on the principle cutting force for the tested condition, with the effect further enhanced by the inclusion of CNTs. Furthermore, with increasing CNT content or depth of cut, the resultant cutting force tends to shift along the cutting direction with a decreased coefficient of friction along the tool/chip interface.