Influence of fibre orientation on cutting force in up and down milling of UD-CFRP composites

Machining of carbon fibre reinforced polymer (CFRP) composites is extremely difficult, mainly due to their inhomogeneous and anisotropic properties. Predicting of cutting force during machining of CFRP is also difficult because the machinability properties of the composite are significantly orientation-dependent (fibre and machining directions). The main objective of the present study is to analyse the influence of fibre orientation on cutting force in milling of unidirectional CFRP. Up and down milling experiences were conducted based on a full factorial design. Experimental data were processed by fast Fourier transformation, regression analysis, and graphical adequate analysis. Multiple-order polynomial models were developed in order to minimise cutting force. Experimental results show that fibre orientation angle significantly influences the cutting force; furthermore, it does not have a significant effect on the passive force component, while the radial force component is more sensitive to the fibre orientation at up milling, than at down milling. An optimal condition is recommended for zig-zag milling of unidirectional CFRPs.