A Taguchi-Grey relational analysis approach to optimizing stiffness and strength in 3D-printed PLA-based composite

The expanding application of polylactic acid (PLA) in advanced sectors like automotive and aerospace is constrained by its inherent mechanical limitations. This research addresses this by developing a PLA composite reinforced with micro-scale talc and nano-scale graphene oxide (GO) via fused deposition modeling (FDM), aiming to synergistically enhance tensile modulus, bending strength, and thermal stability. An integrated Taguchi design and Grey Relational Analysis (GRA) were employed to optimize four key parameters: talc content, GO content, print speed, and nozzle temperature. DSC and TGA analyses confirmed that the incorporation of talc and GO enhanced the thermal stability of PLA, increasing the crystallization temperature from 128.5°C to 135.8°C and the decomposition onset temperature from 299°C to 341°C. The Taguchi-GRA optimization identified nozzle temperature and GO content as the most significant factors affecting mechanical properties. The GRA-derived optimal set—5 wt% talc, 1 wt% GO, 30 mm/s print speed, and 215°C nozzle temperature—yielded the superior balance of mechanical properties, which was correlated through SEM analysis to excellent filler dispersion and robust interlayer adhesion. This study provides a systematic framework for the multi-objective optimization of 3D-printed biocomposites, delivering a specific material-process solution to advance the performance of additively manufactured PLA for functional applications.