Die swell as an objective in the design of polymer extrusion dies

Siegbert, Roland; Behr, Marek; Elgeti, Stefanie

doi:10.1063/1.4963540

Cited by 5 publications

(2 citation statements)

References 4 publications

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“…As said above, the quantitative measure of this effect depends on the length of the die (capillary). The die swell should be taken into account in the design of the processing equipment [ 30 ], and this is especially important when designing spinnerets in fiber spinning since the dies in these devices are always very short.…”

Section: The Role Of Elasticity In Polymer Processingmentioning

confidence: 99%

The Elasticity of Polymer Melts and Solutions in Shear and Extension Flows

2023

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This review is devoted to understanding the role of elasticity in the main flow modes of polymeric viscoelastic liquids—shearing and extension. The flow through short capillaries is the central topic for discussing the input of elasticity to the effects, which are especially interesting for shear. An analysis of the experimental data made it possible to show that the energy losses in such flows are determined by the Deborah and Weissenberg numbers. These criteria are responsible for abnormally high entrance effects, as well as for mechanical losses in short capillaries. In addition, the Weissenberg number determines the threshold of the flow instability due to the liquid-to-solid transition. In extension, this criterion shows whether deformation takes place as flow or as elastic strain. However, the stability of a free jet in extension depends not only on the viscoelastic properties of a polymeric substance but also on the driving forces: gravity, surface tension, etc. An analysis of the influence of different force combinations on the shape of the stretched jet is presented. The concept of the role of elasticity in the deformation of polymeric liquids is crucial for any kind of polymer processing.

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Section: The Role Of Elasticity In Polymer Processingmentioning

confidence: 99%

The Elasticity of Polymer Melts and Solutions in Shear and Extension Flows

2023

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“…The flow-balance method has been widely used. Pauli et al [15] and Siegbert et al [16] adopted space-time finite element method to the optimization of die design, which flow balance and homogeneous die swell were used as the design objectives. Yilmaz et al [17] took uniformity of velocity distribution at the die exit as an objective function.…”

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confidence: 99%

Improved inverse design method for thin-wall hollow profiled polymer extrusion die based on FEM-CFD simulations

Zhang

Huang

et al. 2020

Int J Adv Manuf Technol

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Extrusion process has excellent capability in continuous manufactures with high production volume, low cost, and steady quality for very complex cross-sectional products. However, manufacturing a proper extrusion die is challenging, but essential for good quality products, which needs to consider many influence factors in the die design. This paper shows an improved inverse design method for thin-wall hollow profiled polymer extrusion die by using computational fluid dynamics simulation. Also, design criteria of the inverse design method for extrusion die are proposed and discussed. The simulation results show that the thickness of the die lip gap can be enlarged with the decreasing of the inlet flow rate. Additionally, it shows that the geometry profile of the die lip gap can be widened with the increasing of the length of the free jet. The analytical results have been verified by experiments and show a good agreement. It is concluded that the improved inverse design method with FEM-CFD simulations can provide better accuracy and significantly reduce the manufacturing difficulty of micro and thin-walled extrusion die.

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Neural networks vs. splines: advances in numerical extruder design

Lee

Hube

Elgeti

2023

Engineering with Computers

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In this paper, we present a novel approach to geometry parameterization that we apply to the design of mixing elements for single-screw extruders. The approach uses neural networks of a specific architecture to automatically learn an appropriate parameterization. This stands in contrast to the so far common user-defined parameterizations. Geometry parameterization is crucial in enabling efficient shape optimization as it allows for optimizing complex shapes using only a few design variables. Recent approaches often utilize computer-aided design (CAD) data in conjunction with spline-based methods where the spline’s control points serve as design variables. Consequently, these approaches rely on the design variables specified by the human designer. This approach results in a significant amount of manual tuning to define a suitable parameterization. In addition, despite this effort, many times the optimization space is often limited to shapes in close proximity to the initial shape. In particular, topological changes are usually not feasible. In this work, we propose a method that circumvents this dilemma by providing low-dimensional, yet flexible shape parametrization using a neural network, which is independent of any computational mesh or analysis methods. Using the neural network for the geometry parameterization extends state-of-the-art methods in that the resulting design space is not restricted to user-prescribed modifications of certain basis shapes. Instead, within the same optimization space, we can interpolate between and explore seemingly unrelated designs. To show the performance of this new approach, we integrate the developed shape parameterization into our numerical design framework for dynamic mixing elements in plastics’ extrusion. Finally, we challenge the novel method in a competitive setting against current free-form deformation-based approaches and demonstrate the method’s performance even at this early stage.

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Die swell as an objective in the design of polymer extrusion dies

Cited by 5 publications

References 4 publications

The Elasticity of Polymer Melts and Solutions in Shear and Extension Flows

The Elasticity of Polymer Melts and Solutions in Shear and Extension Flows

Improved inverse design method for thin-wall hollow profiled polymer extrusion die based on FEM-CFD simulations

Neural networks vs. splines: advances in numerical extruder design

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