Experimental and analytical study of the polymer melt flow through the hot-end in material extrusion additive manufacturing

Serdeczny, Marcin P.; Comminal, Raphaël; Pedersen, David Bue; Spangenberg, Jon

doi:10.1016/j.addma.2019.100997

Cited by 48 publications

(81 citation statements)

References 34 publications

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“…They found that the feeding force becomes unstable before reaching the failure velocity. This observation was confirmed by Serdeczny et al [26], where a model to estimate the maximum feeding rate before the extrusion becomes unstable was presented. It was hypothesized that the maximum feeding rate is limited by the heat transfer and the ability to melt the filament completely before it reaches the nozzle contraction.…”

Section: Introductionsupporting

confidence: 62%

“…At some critical feeding rate, called the maximum feeding rate, the force curve changes slope and oscillations appear, which indicates unstable extrusion. It is noted that these instabilities are distinct from the shark skin and melt fracture extrusion instability, as they occur at a lower frequency and are not related to change in the appearance of the extrudate surface [26]. A similar behavior of the feeding force was measured in [25].…”

Section: Comparison With Experimental Resultsmentioning

confidence: 60%

“…First, the numerical simulation is validated with experimental measurements of the filament feeding force when a neat ABS filament ( = 0) is extruded. The filament feeding force is the force required to push the filament through the hot-end system and it was measured in [26,40] using a load cell, where a detailed description can be found. The comparison of the simulated and measured feeding force as a function of the feeding rate can be seen in Fig.…”

Section: Comparison With Experimental Resultsmentioning

confidence: 99%

“…The value of ℎ is unknown and was found through comparison with experimental measurements of the filament feeding force during extrusion of neat ABS. The measurements and their results are discussed in detail in [26]. It was found that the simulation represents the measurements most closely, when ℎ ≈ 600 W/(m 2 K) in the fully developed flow region, and ℎ ≈ 8000 W/(m 2 K) close to the inlet of the channel where a recirculation of the flow occurs.…”

Section: Implementation Detailsmentioning

confidence: 86%

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Influence of Fibers on the Flow Through the Hot-End in Material Extrusion Additive Manufacturing

Serdeczny

Comminal

Pedersen

et al. 2020

Industrializing Additive Manufacturing

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Advancements in material extrusion additive manufacturing are driven by the need of fast production of high-quality parts. A key innovation was the introduction of short fibers into the built filament, which substantially improve the strength of manufactured components. However, the presence of fibers also affects the viscosity and thermal conductivity of the filament, which are important parameters for the extrusion flow and thus the maximum printing speed. In this paper, we numerically study the effect of fibers on the polymer flow and pressure drop inside the nozzle, which determines the maximum extrusion rate. The thermoplastic polymer flow is simulated with a non-isothermal computational fluid dynamics model and the inclusion of fibers is treated with a continuum approach. The simulations are performed for ABS polymer with short carbon fibers, however, other thermoplastic systems with short fibers (e.g. glass, wood, or nylon) can be integrated into the model. The model provides a virtual window into the process and illustrates that while fibers increase the viscosity of the filament and the pressure drop, they also improve the thermal conductivity and lead to faster melting of the polymer, which has an opposite effect on the pressure drop. Finally, the model quantifies the relationship between the fiber volume fraction and the maximum extrusion rate.

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Section: Introductionsupporting

confidence: 62%

Section: Comparison With Experimental Resultsmentioning

confidence: 60%

Section: Comparison With Experimental Resultsmentioning

confidence: 99%

Section: Implementation Detailsmentioning

confidence: 86%

See 2 more Smart Citations

Influence of Fibers on the Flow Through the Hot-End in Material Extrusion Additive Manufacturing

Serdeczny

Comminal

Pedersen

et al. 2020

Industrializing Additive Manufacturing

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“…The most applied technique is extrusionbased 3DCP [3], which is the focus of this study. The 3DPC process steps are adapted from material extrusion additive manufacturing of polymers [4], where the printer tool path is generated by a slicing software in the form of a G-code, which is based on a STL file that constitutes a virtual 3D representation of the structure.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of multi-layer 3D concrete printing

Spangenberg

Silva²,

Comminal³

et al. 2021

RILEM Tech Lett

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This paper presents a computational fluid dynamics model fit for multi-layer 3D Concrete Printing. The numerical model utilizes an elasto-visco-plastic constitutive model to mimic the flow behaviour of the cementitious material. To validate the model, simulation data is compared to experimental data from 3D printed walls. The obtained results show that the numerical model can reproduce the experimental results with high accuracy and quantify the extrusion load imposed upon the layers. Such load is found to exceed the material’s yields stress in certain regions of previously printed layers, leading to layer deformation/flow. The developed and validated numerical model can assist in identifying optimal printing strategies, reducing the number of costly experimental print failures and human-process interaction. By doing so, the findings of this paper helps 3D Concrete Printing move a step closer to a truly digital fabrication process.

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Materials Requirements in Fused Filament Fabrication: A Framework for the Design of Next‐Generation 3D Printable Thermoplastics and Composites

Sola

2022

Macro Materials & Eng

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Fused filament fabrication (FFF), also known as fused deposition modeling, is the leading technology for polymer-based additive manufacturing. The simplicity, along with the cleanness, the affordability, and the multi-material capability, are some of the main advantages that have prompted this success. Nonetheless, the uptake of FFF in industry is hampered by the limited functionality of commercial filaments, that are often based on plain thermoplastics. The future growth of FFF into new markets needs a significant improvement of available materials. However, materials requirements in FFF are complicated and often mutually conflicting. Whereas heuristic approaches to materials design imply significant costs in terms of time, energy, and materials, a critical survey of the main requirements that a new material should fulfill in order to be printable and suitable for commercial adoption is still missing. In order to bridge this gap, the present paper analyzes the workflow from filament production to end-of-life disposal of printed objects, and, for each step, brings to light the governing materials properties. Wherever possible, practical guidelines are given on acceptable values. Existing lacks of knowledge are identified to direct future studies. The ultimate goal is to provide a road map to making materials development in FFF more efficient.

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Experimental and analytical study of the polymer melt flow through the hot-end in material extrusion additive manufacturing

Cited by 48 publications

References 34 publications

Influence of Fibers on the Flow Through the Hot-End in Material Extrusion Additive Manufacturing

Influence of Fibers on the Flow Through the Hot-End in Material Extrusion Additive Manufacturing

Numerical simulation of multi-layer 3D concrete printing

Materials Requirements in Fused Filament Fabrication: A Framework for the Design of Next‐Generation 3D Printable Thermoplastics and Composites

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