Effect of fiber orientations on dynamic mechanical and machinability behavior of flax polymer composites

Although Natural Fiber Reinforced Polymer Composites (NFRPCs) have been taken special place in the aerospace, automotive and construction sectors, owing to their sustainability and mechanical qualities, yet challenges continue in understanding their machining characteristics, especially when executing the slotting operation on the composite surfaces. In these footsteps current investigation is undertaken to study the effect of the fiber orientations on dynamic mechanical properties and milling behavior of flax fiber reinforced epoxy (FREp) composites. These composites are fabricated using hand layup process and designated as Type A (0/90°) and Type B (±45°) based on their reinforcement orientation. Dynamic mechanical experimental results showed that, Type A composite exhibited higher storage modulus property (E′). Though Type B composites suffer in storage modulus, exhibited higher loss modulus (E″) and damping properties than Type A composites due to their angled fiber structure which favors for increased internal friction and higher shear deformation with higher energy dissipation. Milling investigation was carried out as per the Taguchi’s design of experiment using L 9 Orthogonal arrays. Input factors namely, spindle speed (750, 1500 and 2250 rpm), feed rate (70, 90, and 110 mm/min) and depth of cut (1, 1.5, and 2 mm) were selected to study their effect of output responses such as cutting force, surface roughness and machinability index. Results revealed that, depth of cut is the main input factor affected the milling performance of the composite followed by cutting speed and feed rate. Moreover, Type A composite was easier to machine than Type B composites due to their fabric architecture. Milled surface of the FREp composites were subjected to field emission scanning electron microscopy (FESEM) to understand the damages endured during machining.