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

Abstract

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.

FDM-Based 3D Printing of Polymer and Associated Composite: A Review on Mechanical Properties, Defects and Treatments

“…Laser treatment eliminated the surface roughness by melting down the peaks and filling the pores on the surface with molten polymer [ 236 ]. Chen et al [ 237 ] conducted laser treatment on a Cu fibre PLA composite and noted that not only the surface quality, but the mechanical properties also improved. The sample treated with a laser with a power of 5 W and having a laser beam diameter of 200 μm had a reduction of its surface roughness by 91%.…”

“… Surface topographies of: ( a ) unpolished Cu/PLA specimen; ( b ) laser polished Cu/PLA specimen with reduced surface roughness; ( c ) unpolished Al/PLA specimen; ( d ) laser polished Al/PLA specimen with reduced surface roughness. ( a , c ): [ 237 ], ( b , d ): [ 238 ]. …”

Biodegradable Poly(Lactic Acid) Nanocomposites for Fused Deposition Modeling 3D Printing

“…Specifically: At all concentrations, PLA/Ag nanowire nanocomposites show antimicrobial properties against E. coli, P. aeruginosa , and S. aureus [ 47 ]. PLA/Al nanocomposites show increased surface quality, decreased surface roughness, increased storage modulus, decreased loss tangent, increased tensile strength, and increased Young’s modulus after laser polishing [ 48 ]. The introduction of mCu-Zn into PLA/wood flour nanocomposites increases the aesthetic appearance by creating a glossy finish while also increasing the antibacterial properties [ 51 ].…”

“…Many industrial applications cannot use FDM-printed parts because fractures occur between layers due to poor interfacial adhesion and low surface quality [ 48 ]. Therefore, modifying FDM PLA nanocomposites to increase this surface quality may increase industrial use of these nanocomposites.…”

“…Incorporating aluminum into nanocomposites produces air-cooled heat exchangers with high thermal conductivity at a low cost. These PLA/Al composites, when laser polished, show increased surface quality, decreased surface roughness, increased storage modulus, decreased loss tangent, increased tensile strength, and increased Young’s modulus [ 48 ]. These enhanced properties arise from the polymers becoming molten on the surface and reforming into a much more dense and interconnected structure during laser polishing.…”