Advances in modeling transport phenomena in material-extrusion additive manufacturing: Coupling momentum, heat, and mass transfer

Das, Arit; McIlroy, Claire; Bortner, Michael J.

doi:10.1007/s40964-020-00137-3

Cited by 28 publications

(20 citation statements)

References 105 publications

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“…The study of melt dynamics inside the FFF nozzle is one of the most important areas of research for development of 3D printing technology. The Cross-WLF and PVT models are not yet integrated with the velocity profile at nozzle outlet to perform numerical studies [42]. This study reveals some valuable insights into the flow behavior of most common polymers such as ABS and PLA inside a typical FFF nozzle.…”

Section: Discussionmentioning

confidence: 99%

Implementation of viscosity and density models for improved numerical analysis of melt flow dynamics in the nozzle during extrusion-based additive manufacturing

et al. 2021

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Fused Filament Fabrication (FFF) is an Additive Manufacturing (AM) process that builds up a part via layer by layer deposition of polymeric material. The purpose of this study is to implement viscosity and density models for improving the assessment of melt flow behavior inside the nozzle during deposition. Numerical simulations are carried out for different combinations of important process parameters like extrusion velocity Ve, extrusion temperature Te, and filament material (Acrylonitrile Butadiene Styrene (ABS) and Polylactic Acid (PLA)). Cross-Williams–Landel–Ferry (Cross-WLF) viscosity and Pressure–Volume–Temperature (PVT) density models are incorporated to get realistic results. Distribution of printing parameters like pressure, temperature, velocity and viscosity inside the nozzle are observed at steady state and their relationship with the print quality is discussed. Effect of the PVT model on polymer deposition is illustrated by comparing it with deposition considering a constant density. Velocity profiles are obtained for the different cases considered and locations where the flow is fully developed, along the axial distance of the nozzle, are determined and termed as stable zones. A direct correlation between the position of the developed melt flow profile and printing quality is established and the best combination of printing parameters is proposed for ABS and PLA. Extended stable zones are obtained for the polymer melt in the nozzle at Ve = 60 mm/s, Te = 220 °C for ABS and Ve = 30 mm/s and Te = 195 °C for PLA and hence, these can be considered as the optimum values of the printing parameters.

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Section: Discussionmentioning

confidence: 99%

Implementation of viscosity and density models for improved numerical analysis of melt flow dynamics in the nozzle during extrusion-based additive manufacturing

et al. 2021

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“…Although there are a few recent works in this topic, [63][64][65] there is still much to investigate regarding the polymer wetting at the interface of deposited layers, evolution of interlayer bond strength, and thermomechanical consolidation post-deposition on the printer bed. [66]…”

Section: Sem Analysismentioning

confidence: 99%

Rheological investigation of nylon‐carbon fiber composites fabricated using material extrusion‐based additive manufacturing

et al. 2021

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Fused filament fabrication (FFF) has seen broad industrial adoption as it is capable of manufaturing large complex parts from robust thermoplastics in a cost-effective manner. However, the mechanical performance of the printed parts is limited due to poor interlayer bonding and the presence of voids. In order to overcome these drawbacks, the addition of short or continuous fibers into the polymer matrix has been investigated, as the fibers can act as a mechanical reinforcement while also mitigating residual stress resulting from the material's rapid solidification following extrusion. Therefore, understanding the implications of process parameters and fiber reinforcements on printed part properties through detailed crystallization analysis and rheological characterizations is of paramount importance. The goal of this study is to understand the process-structure-property relationships of short carbon fiberreinforced polyamide 6 (CF-PA6) by comparing the melt rheology and crystallinity of CF-PA6 versus a neat PA6 polymer. Differences in the melting and crystallization behavior resulting from the reinforcing fibers revealed an increased time window for crystallization in the fiber-reinforced matrix. Rheological characterizations at the recommended printing temperatures demonstrate the shear-thinning behavior of the samples at shear rates relevant to FFF. From a statistical design of experiments analysis, the layer thickness was found to be the most significant parameter affecting the tensile properties of a printed part at a constant printing temperature and printing speed. The tensile fracture surfaces of the printed specimens using scanning electron microscopy were analyzed to provide insights into the failure mechanisms as a function of AM processing variables.

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“…Although (FFF)-3D printing has attracted significant attention in recent years, several review papers on the 3D printing of polymeric (or even composite) materials have focused on critical characteristics and challenges, such as the mechanical properties of fabricated parts, application of various materials, and the process design [13,[26][27][28][29]. Based on the existence of review papers that consider the different aspects of the FFF, such as heat transfer [30], further review on the in-process monitoring of the temperature profile during FFF is still missing. This paper contributes to persuading readers of its noteworthy aspect of heat transfer and its remarkable impact on the bonding/strength of 3D-printed parts.…”

Section: Introductionmentioning

confidence: 99%

In-Process Monitoring of Temperature Evolution during Fused Filament Fabrication: A Journey from Numerical to Experimental Approaches

Vanaei

Shirinbayan

Deligant

et al. 2021

Thermo

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Fused filament fabrication (FFF), an additive manufacturing technique, unlocks alternative possibilities for the production of complex geometries. In this process, the layer-by-layer deposition mechanism and several heat sources make it a thermally driven process. As heat transfer plays a particular role and determines the temperature history of the merging filaments, the in-process monitoring of the temperature profile guarantees the optimization purposes and thus the improvement of interlayer adhesion. In this review, we document the role of heat transfer in bond formation. In addition, efforts have been carried out to evaluate the correlation of FFF parameters and heat transfer and their effect on part quality. The main objective of this review paper is to provide a comprehensive study on the in-process monitoring of the filament’s temperature profile by presenting and contributing a comparison through the literature.

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Advances in modeling transport phenomena in material-extrusion additive manufacturing: Coupling momentum, heat, and mass transfer

Cited by 28 publications

References 105 publications

Implementation of viscosity and density models for improved numerical analysis of melt flow dynamics in the nozzle during extrusion-based additive manufacturing

Implementation of viscosity and density models for improved numerical analysis of melt flow dynamics in the nozzle during extrusion-based additive manufacturing

Rheological investigation of nylon‐carbon fiber composites fabricated using material extrusion‐based additive manufacturing

In-Process Monitoring of Temperature Evolution during Fused Filament Fabrication: A Journey from Numerical to Experimental Approaches

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