Laser polishing of Cu/PLA composite parts fabricated by fused deposition modeling: Analysis of surface finish and mechanical properties

Fused deposition modeling (FDM) technology decreases production time and cost in engineering industry, but with typical low surface quality. In this study, laser polishing was employed to improve surface quality of copper fiber/polylactide acid (Cu/PLA) composite parts fabricated by FDM. Surface roughness, surface morphology, dynamic mechanical analysis (DMA), and tensile properties were studied. The results showed that after laser polishing, the surface roughness was reduced by more than 91% (from 10.52 to 0.87 μm Sa) at the optimized parameters (the laser power of 5 W and the laser beam diameter of 200 μm). Laser polishing can effectively remove surface defects formed during FDM. DMA showed that the storage modulus, loss modulus, and glass transition temperature of Cu/PLA composites were significantly improved, because the Cu fibers and PLA matrix formed a strong interfacial adhesion after treatment. Moreover, the tensile strength and Young's modulus of the Cu/PLA composites sample also improved by laser polishing. The fracture morphologies were observed, and the possible strengthening mechanism was also discussed.