The essence of cutting carbon fibre-reinforced plastic (CFRP) composites is a process of material failure and chip formation. The mechanism of cutting CFRPs can be explained from the perspective of local removal of material on the microscopic level. The morphology of the chips resulting from the cutting process can be determined from the perspective of the overall failure of the material on the macroscopic level. To reveal the mechanism of cutting CFRPs at both levels, a macroscopic model and a microscopic model are established in this study. Orthogonal cutting is applied in both of the models to illuminate the removal process. Combined with experimental observations, the results that obtained from both the macroscopic and microscopic level revealed the different mechanics of cutting CFRPs for different fibre orientations. For example, the forms of fracture that occur at 0° fibre orientation are primary interface cracking and fibre bending; the resulting chips have long shapes.
The cutting edge of the polycrystalline diamond tool easily blunts in high-speed milling of carbon-fiber-reinforced plastic with the tool deterioration. It aggravates the burrs damage due to the change in the tool–material interaction. Therefore, this paper analyzes the tool–material interaction in milling of carbon-fiber-reinforced plastic based on the material-removal mechanism to investigate the tool deterioration mechanism. It reveals that there are two main reasons for the tool deterioration: the extreme crashing and ploughing of the uncut fibers on the tool, and the serious impact of fibers strongly supported on the cutting edge. An indirect measure method is proposed to quantify the tool deterioration including the ploughing-caused wear and impact-caused microchipping. Furthermore, the milling tests are performed to evaluate the tool deterioration under different cutting speeds in the range of 7.33–9.42 m/s. Meanwhile, a modified mathematical model of tool life is proposed based on a strict burr specification in milling of the carbon-fiber-reinforced plastics. Polycrystalline diamond tool has the longest life with the run-in wear and the quasi-steady-state wear for 7.33 m/s cutting speed, and the life rapidly decreases with the increase in the cutting speed in this range. For the cutting speed larger than 8.37 m/s, the wear resistance of polycrystalline diamond tool is very low, because the accelerated state wear occurs instead of the quasi-steady-state wear. Thus, the optimization of the tool geometry and the assisted lubrication should be applied for its improvement.
The milling process is always required to achieve dimensional tolerance for the near-net-shape carbon fiber reinforced polymer (CFRP) parts. However, delamination and cracking are inevitably induced in milling CFRP due to the excessive milling forces. The milling forces should be thereby well controlled to reduce damages of CFRP parts. Developing a theoretical milling force model is an effective approach to understand the mechanism of milling force generation. Recent studies have established the predictive models; however, the interlaminar effect impacting the material removal process is not considered during milling multidirectional CFRP laminate, limiting the predictive model accuracy. In this work, a model of dynamic milling force for multidirectional CFRP laminate was developed by considering the interlaminar effect for the first time. The specific cutting energy predicted by the artificial neural network methodology was employed to calculate the milling forces during milling a single CFRP layer. Meantime, the support of the layer was enhanced due to the interlaminar effect, and the correction coefficients for each type of support were proposed to reflect the role of this effect. Then, the overall milling forces for multidirectional CFRP laminate can be obtained via the superposition principle, which agreed well with the experimentally measured results.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.