ABSTRACT
The extrusion-based 3D printing has become popular in recent years due to the emergence of open source projects and low-cost machines that have made the technology accessible to all levels of users. In parallel, new materials, in general thermoplastic filaments, are inserted in the market for application in this type of manufacturing technique, making it increasingly necessary to develop experimental characterization studies to provide technical data to users. Thus, we sought to study poly(ethylene terephthalate glycol) (PETG), a polymer of recent adoption in this context, and compare it to poly(lactic acid) (PLA), the most popular one in this field. Both materials were mechanically analyzed by traction through samples made by 3D printing varying the angles of deposition of the extruded material. The same type of analysis was made using parts built by injection molding, for comparison purposes. The materials in their initial filamentary state were thermally evaluated by TGA and DSC, and chemically evaluated by FTIR. The last two characterization techniques were also applied to the polymers after the injection and 3D printing processing. The results showed that the tensile mechanical properties of the printed components are strongly influenced by the orientation of the filaments deposited in the layers and by the mesostructure of the parts. PLA has mechanical superiority, greater maximum tension and high rigidity, in relation to PETG, in the injected and printed samples. PETG, in turn, has shown to be more resistant to thermal degradation, more thermally stable (because it does not show significant changes in its thermal behavior after being processed), and more flexible, which is very interesting for 3D printing applications. Finally, the molecular chemical structure of both polymers was similar to that described in other studies found in the literature and was slightly altered by the manufacturing processes.
Keywords
3D Printing; injection molding; PLA; PETG; characterization techniques
