Circular economy-driven repair of 3D printed Polylactic Acid (PLA) by Fused Deposition Modelling (FDM) through statistical approach

Leveraging 3D printing technology for the repair of damaged plastic parts provides a sustainable solution for the plastics industry, aligning with the principles of the circular economy. This study specifically focuses on the repair of Polylactic Acid (PLA) specimens produced via Fused Deposition Modelling (FDM), employing tough PLA as the repair material. The research investigates the optimization of key repair parameters, including infill pattern shape, infill percentage, and raster angle of the repair filler. Utilizing Ultimaker Cura software, 3D models of both substrate and filler parts were sliced to facilitate this analysis. The study employs Response Surface Methodology (RSM) to evaluate how variations in these parameters affect output responses such as build time, weight, maximum failure load, and elongation at break percentage. Mechanical properties were assessed through tensile tests comparing repaired specimens to standard non-repaired counterparts. Statistical analysis via Analysis of Variance (ANOVA) was conducted to validate the significance of the experimental findings. The results indicate that adjusting raster angle and infill percentage can enhance build time and elongation at break. The optimization process identified a Tri-hexagon infill pattern with a 30 % infill percentage and a raster angle of 58° as the most effective configuration for repairs. Additionally, alternative configurations like Cubic-Subdivision and Lines demonstrated significant benefits, achieving nearly a 4 % reduction in build time, a 5 % decrease in part weight, a 3 % increase in maximum failure load, and a remarkable 27 % increase in elongation at break. In conclusion, this study underscores the viability of optimized 3D printing techniques for repairing plastic parts, thereby extending their lifespan and contributing to sustainability within the industry. The findings advocate for broader adoption of printing-based repair in practical applications, emphasizing their potential to significantly reduce waste associated with product replacement.