Thermo-mechanical Effects in Mechanical Polishing of Natural Fiber Composites

Abstract

Efficient machining and finishing of natural fiber reinforced plastic (NFRP) composites is essential for realizing the industrial application envisaged of these promising, environmentally friendly materials. While prior efforts allude to the multiscale nature of their material removal mechanisms, little understanding currently exists on the thermal effects of their material removal behaviors. This experimental study aims to characterize the thermal effects during the polishing of NFRP composites. For this aim, dry and wet polishing have been performed following several polishing steps on unidirectional flax fibers reinforced polypropylene composites. Results from scanning electron microscopy (SEM) and optical interferometry studies reveal a significant difference between dry and wet polishing in terms of surface artifacts induced. This difference is enhanced at higher sliding speed, indicating that the asperity removal during polishing is mostly thermally mediated. The results also indicate that the surface forming of flax fibers is related to the mechanical contact scale engendered by the grit size.