Micro-end-milling of carbon nanotube reinforced epoxy nanocomposites manufactured using three roll mill technique

Abstract

Carbon nanotubes (CNTs) have been applied as nano-fillers to improve mechanical, thermal and electrical properties of polymers. Despite near net shape techniques could be used to manufacture nanocomposites, micromachining processes are still necessary to attain high surface quality and dimensional accuracy. Besides, micromachining of nanocomposites could be a potential approach to produce micro-features/components, following the miniaturisation trend of modern manufacturing. Therefore, micro-machining of these relatively new materials needs to be investigated. A comprehensive investigation on machinability of nanocomposites will be presented in terms of chip formation, cutting force, tool wear, surface morphology and surface roughness. Three controlled quantitative factors are investigated at different levels, including filler loading, cutting speed and feed per tooth (FPT). Micro-slotting is performed on an ultra-precision desktop micro-machine tool using uncoated carbide micro-end mill. The additions of multi-walled carbon nanotube (MWCNT) have shown significant effects on the machinability of these epoxy-based nanocomposites including a dramatic reduction in cutting force and machined surface roughness with accelerating tool wear compared with a neat polymer. The irregular cutting force variations when micro-milling epoxy/MWCNT nanocomposites at feed rates below minimum uncut chip thickness (MUCT) (lower than 2 μm) indicating by their fluctuations that different from those in higher feed rates. It possibly shows the impact of size effects that are illustrated by the observations of chip formation, surface morphology, cutting force profiles as well as specific cutting energy calculation.