Influence of controlled oxygen levels on tensile strength, surface roughness, and warping in FDM prints

• Main Author: Mat, Muhamad Arifuddin Che
• Format: Thesis
• Language: English; English
• Published: 2024
• Online Access: http://eprints.utem.edu.my/id/eprint/28846/; https://plh.utem.edu.my/cgi-bin/koha/opac-detail.pl?biblionumber=124495

Fused deposition modeling (FDM) is one of the most widely utilized additive manufacturing techniques. However, the main limitations of FDM are poor surface roughness, low tensile strength, and significant warping deformation, which affect manufacturability and hinder the precision and quality of printed components. This study presents a new technique that improves the quality of FDM printed specimens by incorporating inert gases, such as nitrogen or argon, into the 3D printing chamber. The chamber was designed with openings for the inert gas to flow in at 12 m³ h⁻¹ and +5 bar pressure and an outlet for gas to be released, monitored by an oxygen detector to control degradation factors. The effect of the inert gas on 3D printed specimens by the objectives, i.e. to investigate the effect of inert gas on the tensile strength of FDM-printed samples under varying printing process parameters, to analyze the surface roughness and bonding formation of the printed samples and to identify warping deformation in the printed samples. The research reveals several key findings. First, Cu/PLA exhibited the highest tensile strength compared to PLA and ABS at a layer thickness of 0.3mm, indicating that increased layer thickness correlates with increased tensile strength. Additionally, Cu/PLA showed superior SEM results, featuring structures with minimal air gaps compared to PLA and ABS. Second, both Ar-O₂(0%) and N₂-O₂(0%) conditions significantly improved tensile strength compared to printing without inert gas, with Ar-O₂(0%) demonstrating the most notable effect by producing uniform interlayer bonding, as evidenced by SEM images. Third, in terms of surface roughness, Cu/PLA outperformed PLA and ABS, with Face 4 achieving the best results under the N₂-O₂(0%) condition. The improvement in surface roughness was up to 24.71% between Face 4 and Face 1 at a 0.2mm layer thickness. SEM images revealed that areas with higher surface roughness correlated with more pronounced surface irregularities, such as grain boundaries and pores. Finally, both N₂-O₂(0%) and Ar-O₂(0%) inert conditions enhanced surface roughness compared to non-inert conditions. SEM analysis indicated that Ar-O₂(0%) produced minimal air gaps, facilitating strong connections between adjacent filaments and reducing void areas. In conclusion, the study affirms that the application of an inert gas environment during 3D printing is a highly effective strategy for improving the mechanical properties and surface quality of printed specimens. The findings offer valuable guidance for future research and development in the field of additive manufacturing, promoting the adoption of advanced techniques to achieve superior material performance and quality in 3D printed products.