Numerical Optimization of Nozzle Shapes for Fused Deposition Modeling

Purpose: In fused deposition modeling (FDM), the nozzle plays a critical role in enabling high printing speeds while maintaining precision. Despite its importance, most applications still rely on standard nozzle designs. This work investigates the influence of nozzle geometry on pressure loss inside the nozzle, a key factor in high-speed printing performance. Design/methodology/approach: We focus on optimizing the nozzle shape to minimize the pressure loss and establish a framework that allows both sim- ple angle-based optimization and more advanced spline-based parametrization. To model the polymer melt flow, we compare two constitutive descriptions commonly employed in the literature: a temperature-dependent, shear-thinning viscous model and an isothermal viscoelastic model. Findings: For the viscous model, the optimal half-opening angle exhibits a strong dependence on the feeding rate, with higher rates favoring half-opening angles near 30°, whereas lower rates are more efficient at larger angles. In con- trast, the viscoelastic model predicts a weaker dependence of the optimal angle on the feeding rate. For both models, spline-based parametrization yields only marginal improvements over angle optimization in terms of reducing pressure loss. Originality/value: This paper presents a comparative study of FDM nozzle shape optimization using different simulation models. We introduce a flexible optimization framework that accommodates both simple and advanced geomet- ric parametrizations. The results highlight the impact of model choice on the optimal nozzle geometry and provide support for improving nozzle design in high-speed printing applications.