The impact of main process control settings on the quality metrics of thermoplastic polysulfone (PSU) in MEX 3D printing: A quantitative interpretation

The increasing demand for high-performance thermoplastics in functional and engineering applications has led to a rise in the research of their processability through additive manufacturing (AM) methods. Polysulfone (PSU) has emerged as an interesting candidate for use in advanced 3D printed components for its high thermal stability, excellent chemical resistance, and good mechanical strength. However, polysulfone has challenges in material extrusion (MEX) printing due to high processing temperature and melt viscosity. This work aims to improve quality metrics (surface quality, porosity, and dimensional accuracy) of PSU parts through processing the MEX process parameters. The experimental manufacturing and evaluation procedures were conducted based on the Taguchi L16 Robust design experimental model. The toolpath orientation angle (TA), nozzle heat level (NHL), deposition speed (DS), structure density (DS), and line width (LW) were selected as control variables. Their effect was evaluated against the average roughness - R a , Root Mean Square roughness - R q , Actual to Nominal Dimensional deviation at 95 % - A2N 95, and Computed Tomography Scan porosity- P CT quality responses. TA had a remarkable effect on roughness responses, SD on dimensional deviation, and NHL on porosity. Data processing was implemented with the reduced quadratic regression model (RQRM) and the quadratic regression model (QRM), with RQRM being selected due to the higher F-values (R 2 values were sufficient for three metrics, ∼65%, while in porosity they were high, ∼82%). The validity of the prediction functions was confirmed by two additional runs (>10% error), advancing the process understanding of HPPS in MEX AM.