Friction reduction mechanism on the grinding interface during nanofluid minimum quantity lubrication grinding FRP

Abstract

Fiber-reinforced resin matrix composites (FRP) are highly abrasive, and there is strong friction between the fibers and the abrasive grain during the grinding process. Nanofluid minimum quantity lubrication (NMQL) is an excellent lubrication technology that can significantly reduce the friction force. To investigate the lubrication performance of different nanoparticles, this study analyzed the friction reduction mechanism of tubular, layered, hexahedral, and spherical nanoparticles on the grinding interface based on tribological theory. Secondly, CNTs, MoS₂, SiC, CuO, and Al₂O₃ were selected to represent tubular, laminar, hexahedral, and spherical nanoparticles for grinding experiments to verify the validity of this mechanism. The results showed that the grinding forces F_n, F_t, and F_r were reduced by 86.7 %, 68.9 %, and 81.2 %, respectively, in the NMQL-Al₂O₃ condition compared to the dry grinding condition. The micro morphology of the grinding surface showed that the fiber damage was the lowest under the NMQL-Al₂O₃ condition. Sa, Sz, and Sq were reduced by 62.9 %, 50.5 %, and 57.8 % under NMQL-Al₂O₃ compared to dry grinding conditions. These results show that high-hardness spherical nanoparticles (Al₂O₃) are beneficial in reducing the friction, have better lubrication performance, and can significantly reduce fiber wear during the FRP grinding process.