Experimental investigation and optimization of process parameters for fused filament fabrication-printed Nylon 6 samples using hybrid Taguchi-CRITIC-water cycle algorithm

Nylon 6 is widely used in construction, manufacturing, electrical, automotive, and packaging sectors, thanks to its excellent tensile strength, toughness, wear resistance, and fatigue resistance properties. In the present work, test specimens made from Nylon 6 feedstock were printed on a Taguchi L9 orthogonal array using the Fused Filament Fabrication (FFF) process, also known as Fused Deposition Modeling (FDM). During experiments, slice thickness, head speed, and layer thickness were considered as the variable input parameters, while ultimate tensile strength, surface roughness, weight, and time were measured as output parameters. A combined approach of Taguchi, CRiteria Importance Through Intercriteria Correlation (CRITIC) method, and Water Cycle algorithm (WCA), namely, the hybrid Taguchi-CRITIC-WCA method, was proposed in the present work to optimize FFF process parameters. The weighted sum of regression models developed for each output characteristic based on experimental data was used as a combined objective function during optimization. The CRITIC method was used to determine the weights for each output characteristic, and the WCA was used to optimize the process parameters. Optimization resulted in achieving maximum tensile strength, minimum surface roughness, weight, and build time of specimen through minimal slice thickness, moderate head speed, and low infill density. The significantly low maximum percentage error of 1.6% during experimental validation of optimized parameter settings indicated the accuracy of the proposed Taguchi-CRITIC-WCA model. The model produced superior optimization performance compared to other non-traditional optimization techniques such as GA and PSO. Finally, the impact of input parameters on output characteristics was analyzed in detail.