A study on micromilling process of multidirectional carbon fiber reinforced plastic composite using nano-solid dry lubrication

In this research, the micromilling process using nano-solid dry lubrication is studied for machining multidirectional carbon fiber reinforced plastic (MD-CFRP). For this lubrication, two kinds of graphene nanoplatelets and multiwall carbon nanotubes are used as nanoparticles. The workpiece is an MD-CFRP composite in which 10 plies of prepreg are laminated, and it consists of four carbon fiber orientations-0 deg, 45 deg, 90 deg, and 135 deg. The micromilling experiments are conducted, and the workpiece surface quality and tool wear are investigated. As a result, it is confirmed that the nano-solid dry lubrication can improve the surface quality and reduce the tool wear. In particular, larger graphene nanoplatelets (xGnP H-5) are more advantageous than smaller graphene nanoplatelets (xGnP C-750). In addition, multiwall carbon nanotubes having a tube-shape structure are less effective than graphene nanoplatelets having a twodimensional thin sheet shape for enhancing the micromilling performances, which may be due to better lubrication effect with the graphene nanoplatelets' sliding phenomenon at the cutting region.