Cutting force model of milling titanium alloy with C60 nanofluid minimum quantity lubrication

The milling of titanium alloy has the characteristics of small deformation coefficient, high cutting temperature and severe tool wear, resulting in poor machining accuracy retention. To solve the above problems, it is proposed to use fullerene C60 nanoparticles mixed with water-based cutting fluid, through Nano Fluid Minimum Quantity Lubrication (NFMQL) in the metal cutting process to improve the milling performance of titanium alloys. To reveal the basic mechanism of titanium alloy processing under various lubrication conditions, flank milling thermal-mechanical coupling modeling method considering lubrication conditions is proposed. The cutting force and temperature model of the infinitesimal element on the milling cutter is established according to the oblique cutting theory and the imaginary heat source method, and the cutting force on the cutting edge is obtained by calculating the shear flow stress according to the Johnson-Cook material constitutive formula, and the element cutting force coordinate is converted into the initial coordinate system. Based on friction and wear experiments, the change of friction characteristics of C60 nanoparticles cutting fluid with different concentrations was measured, when the concentration of C60 cutting fluid is 200 ppm, the friction coefficient is the lowest. Milling experiments show that water-based C60 NFMQL has good lubrication and cooling effects, and the maximum milling force of 200 ppm concentration is reduced by about 26 % and 16.4 % compared with flood milling and pure MQL. By comparing the predicted curve with the cutting force of flank milling, the milling force predicted by the model is basically consistent with the measured value in the trend and value.