Enhanced Mechanical Properties and Surface Finish of PLA 3D Prints via Combined Heat Annealing and Powder Coating

In this study, we investigate a novel post-processing approach combining heat annealing and powder coating to enhance both the mechanical performance and surface finish of polylactic acid (PLA) 3D-printed components. Previous work demonstrated that annealing PLA at temperatures between 100 and 120 °C significantly improves its mechanical properties. Building on this, we explore the effects of applying medium-density fiberboard (MDF) powder coating, which cures at a similar temperature range, to simultaneously improve the material’s surface aesthetics. Test specimens were printed with identical parameters and subjected to heat treatment at 120 °C for varying durations (0 to 15 min, in one-minute intervals). Additional observations included dimensional stability and surface uniformity. The results indicate a clear correlation between post-processing time and improvements in both strength and surface appearance, with optimal outcomes observed between 5 and 8 min of curing. This combined post-processing method provides a cost-effective and accessible way to enhance part performance and aesthetics, thereby expanding the applications of PLA-based additive manufacturing, particularly in functional and design-focused use cases.