High performance polysulfone (PSU) mechanical response in additive manufacturing: Optimization of critical control settings

High-performance polymers (HPPs) operate in demanding environments. Therefore, exploiting their specs to the maximum is critical, considering also their high cost. Investigating Polysulfone (PSU) in material extrusion (MEX) 3D printing is challenging due to processability issues. Therefore, it is still inadequately studied, while the 3D printing parameters are expected to affect its mechanical performance. To examine the influence of critical process variables on the mechanical and thermal properties of HPP PSU samples, a series of test specimens were fabricated using the MEX 3D printing technique. A comprehensive experimental design modeling approach, specifically the Taguchi L16 method, was employed. Five control factors, each at four levels, were considered: raster angle, head speed, nozzle temperature, fill density, and strand width. The mechanical response of the printed specimens was evaluated through measurements of tensile strength, Young's modulus, tensile toughness, and tensile yield strength. The experimental data also facilitated the application of two regression models to interpret the obtained results. The thermal stability and phase transition of PSU were examined using differential scanning calorimetry and thermogravimetric analysis. The microstructural characteristics of the printed parts were evaluated via scanning electron microscopy. Optimization achieved more than 200% improvement in three of the four response metrics (163% in the fourth one). Prediction models achieved less than 10% error in confirmation runs, while R 2 was found to be higher than 85% confirming the prediction accuracy. Exploiting the reported findings, the examined mechanical, thermal, and microstructural properties of the MEX-printed PSU can be predicted in real-life applications, enabling future innovations in additive manufacturing processes for high-performance polymers.