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 two-dimensional 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.