Modification the surface quality and mechanical properties by laser polishing of Al/PLA part manufactured by fused deposition modeling

Abstract

Owing to the layer-by-layer deposition characteristic of fused deposition modeling (FDM) process, parts produced via FDM have typical low surface quality and do not satisfy the requirements for end-use applications. Therefore, it is necessary to improve the surface quality of parts produced via FDM. In this study, laser polishing technology was employed to enhance the surface quality of aluminum fiber/polylactide acid (Al/PLA) composite parts produced via FDM. The surface roughness, surface morphology, dynamic mechanical properties, and tensile properties were investigated. With optimal polishing parameters, the laser polishing process removed the defects formed during the FDM process. The surface roughness was reduced from the initial value of 5.64 μm to 0.32 μm (Ra). The dynamic mechanical analysis (DMA) results showed that there was a remarkable improvement in the storage modulus (E′), loss modulus (E"), and glass transition temperature of Al/PLA composite specimens after laser polishing. The re-melted and polished surface of the specimens also led to improvement in the tensile strength and Young's modulus. Lastly, the fracture morphologies were observed, and the possible strengthening mechanism was also discussed. These results indicate that laser polishing can be an efficient method for the surface polishing of FDM-printed parts.