The increasing global emphasis on sustainable manufacturing has stimulated growing interest in natural fibre-reinforced polymer composites as lightweight alternatives to synthetic counterparts in automotive applications. This study presents a comprehensive machinability assessment of bamboo-reinforced epoxy composites fabricated using two indigenous Nigerian bamboo species—Bambusa vulgaris and Oxytenanthera abyssinica—as reinforcement in a bisphenol-A diglycidyl ether epoxy matrix. Composite laminates were prepared via hand lay-up with fibre volume fractions of 30%, 40%, and 50%, followed by post-cure consolidation. Machinability was evaluated through drilling and milling operations conducted on a CNC machining centre under varied cutting speed (50–200 m/min), feed rate (0.05–0.20 mm/rev), and depth of cut (0.5–1.5 mm) combinations. Response variables included surface roughness (Ra), thrust force, delamination factor (Fd), material removal rate (MRR), and tool wear. Results indicate that Bambusa vulgaris composites with 40% fibre volume fraction yielded the most favourable machinability window, with Ra values as low as 1.23 µm, thrust force of 42.6 N, and delamination factor of 1.08 under optimised cutting parameters. Scanning electron microscopy of machined surfaces revealed that fibre pull-out, matrix micro-cracking, and thermal degradation were the dominant damage mechanisms. Taguchi L18 orthogonal array and analysis of variance (ANOVA) confirmed that cutting speed and fibre volume fraction are the most statistically significant factors governing surface quality. The specific mechanical properties and machinability characteristics of the developed composites are benchmarked against requirements for automotive interior panels, door liners, and dashboard substrates, confirming the technical feasibility of these bio-composites for industrial deployment in the Nigerian automotive sector.
Publication Date: 2026-06-15