Machining temperature comparative analysis of end mill and novel tool in orbital drilling of CFRP composite

Applying Carbon fiber-reinforced plastics (CFRPs) instead of traditional materials can improve the structural strength and reduce the weight of the spacecraft. However, the defects and the rejections still impede the wide application of CFRP for the contrasting thermo-mechanical properties of fibers and resin. A lower machining temperature can reduce burrs and delamination effectively. To study the cutting temperature of orbital drilling in CFRP, the processing temperature of the conventional orbital drilling (COD) was compared with the novel orbital drilling and reaming tool (ODR), and a heat transfer model considering the influence of convective heat transfer on cutting temperature was also proposed in this research, which can explain the reason of the novel tool with a lower cutting temperature. On the basis of the analysis of the kinematic mechanisms, a cutting force prediction model for the process of orbital drilling was presented. The three-dimensional, unsteady state, nonhomogeneous partial differential heat transfer equation in polar coordinates was established, and solved with the finite difference approach. The results show that the predictions of models are coincided to the experimental data, and ODR tool can reduce the processing temperature of orbital drilling effectively.