Fiber type effect on tribological behavior when cutting natural fiber reinforced plastics

• We study the milling of natural fiber reinforced plastic (NFRP) composites.
• We make an energetic analysis of cutting mechanisms of NFRP.
• We introduce the multiscale analysis of machined surfaces of NFRP.
• The effect of natural fiber type is more relevant at fiber bundle scales.
• NFRP surface roughness decreases linearly with the increasing of fiber stiffness.

Recently, natural fiber reinforced plastic (NFRP) materials are becoming a viable alternative to synthetic fiber in many industrial applications which do not require high structural performances. However, machining of NFRP such as milling process is almost unavoidable operation to facilitate the parts assembly in addition to the finishing of final products. The present study thus focused on the influence of natural fiber types on tribological behavior during profile milling process. Three types of short natural fibers (bamboo, sisal and miscanthus) reinforced polypropylene (PP) composites are investigated. The quality of NFRP machined surface is quantified using a multiscale analysis based on wavelets decomposition. The natural fiber effects related to the machined surface quality is hence identified at all scales from roughness to waviness. The bamboo fibers reinforced plastics which exhibit high contact stiffness show the smoother surface finish after machining. Therefore, the multiscale surface roughness is used as descriptor of natural fiber influence on the machining mechanisms and to establish the cutting signature of NFRP materials.