🤖 AI Summary
In high-speed fused deposition modeling (FDM), nozzle geometry critically influences melt flow pressure loss, yet existing studies predominantly rely on conventional, fixed-geometry designs. Method: This work establishes a flexible shape optimization framework parameterized by both taper angle and B-spline profiles, integrated with a temperature-dependent shear-thinning viscosity model and an isothermal viscoelastic constitutive model. Comprehensive numerical simulations and comparative analyses are conducted across multiple processing conditions. Results: Under the viscous model, the optimal half-taper angle exhibits strong sensitivity to feed rate; viscoelastic effects markedly reduce this sensitivity. B-spline parameterization yields only marginal pressure drop reduction (<2%), confirming the engineering validity of simplified angular parameterization. The study demonstrates that constitutive model selection fundamentally governs the nozzle optimization trajectory, providing both theoretical insight and practical methodology for rational design of high-speed FDM nozzles.
📝 Abstract
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.