Modeling of extrusion-based additive manufacturing for pelletized thermoplastics: Analytical relationships between process parameters and extrusion outcomes

Pricci, Alessio; Tullio, Marco D. de; Percoco, Gianluca

doi:10.1016/j.cirpj.2022.11.020

Cited by 6 publications

(6 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These pellet-fed systems allow for higher deposition rates while simultaneously reducing the cost of the raw materials. Recently, Pricci et al [3] presented a sophisticated model to correlate the screw speed for a pellet-fed system similar to that of Duty et al to that of the desired mass flow rate. Similarly, Barera et al [4] studied the impact of the temperature and extrusion pressure on the final part performance for carbon fiber-filled polyamide 6.…”

Section: Introductionmentioning

confidence: 99%

Fiber Orientation Quantification for Large Area Additively Manufactured Parts Using SEM Imaging

Nargis,

Jack

2023

Polymers

View full text Add to dashboard Cite

Polymer-based additively manufactured parts are increasing in popularity for industrial applications due to their ease of manufacturing and design form freedom, but their structural and thermal performances are often limited to those of the base polymer system. These limitations can be mitigated by the addition of carbon fiber reinforcements to the polymer matrix, which enhances both the structural performance and the dimensional stability during cooling. The local fiber orientation within the processed beads directly impacts the mechanical and thermal performances, and correlating the orientation to processing parameter variations would lead to better part quality. This study presents a novel approach for analyzing the spatially varying fiber orientation through the use of scanning electron microscopy (SEM). This paper presents the sample preparation procedure including SEM image acquisition and analysis methods to quantify the internal fiber orientation of additively manufactured carbon fiber-reinforced composites. Large area additively manufactured beads with 13% by weight large aspect ratio carbon fiber-reinforced acrylonitrile butadiene styrene (ABS) pellets are the feedstock used in this study. Fiber orientation is quantified using the method of ellipses (MoE), and the spatial change in fiber orientation across the deposited bead cross-section is studied as a function of process parameters including extrusion speed, raster height, and extrusion temperature zones. The results in the present paper show the results from the novel use of SEM to obtain the local fiber orientation, and results show the variation in alignment within the individual processed bead as well as an overall aligned orientation state along the direction of deposition.

show abstract

Section: Introductionmentioning

confidence: 99%

Fiber Orientation Quantification for Large Area Additively Manufactured Parts Using SEM Imaging

Nargis,

Jack

2023

Polymers

View full text Add to dashboard Cite

show abstract

“…At increasing D * , mass flow rate rises almost linearly; this is due to the lower counterpressure which develops in PAM extrusion [29].…”

Section: Fig 3 Mean Extruded Mass Flow Rate At Different Values Of Th...mentioning

confidence: 94%

“…The pressure starts to rise in the solid-conveying zone, up to the last screw vanes. Then, it drops in the nozzle and deposited layer, up to the atmospheric value [29].…”

Section: Experimental Investigationmentioning

confidence: 99%

Non-Newtonian, non-isothermal three-dimensional modeling of strand deposition in screw-based material extrusion

Pricci

2023

Materials Research Proceedings

View full text Add to dashboard Cite

Abstract. Material extrusion (MEX) is one of the most widespread additive manufacturing techniques. Among the MEX processes, pellet additive manufacturing (PAM) is of primary interest in industry 4.0 scenario, mainly because of the lower unit cost, energy consumption and waste production, together with the wider range of printable materials. Mechanical properties are related to the intra and inter layer bonding, which in turn depends on the strand geometry. For the first time, the relationship between PAM processing parameters and layer morphology has been studied by means of non-Newtonian, non-isothermal three-dimensional numerical simulations; the influence on mass flow rate and strand shape has been investigated. A very good correspondence between experiments and numerical computations of layer shape was found. Thermal contact area increases at lower layer heights, but counterpressure limits the extruded mass flow rate. This effect can be mitigated by choosing higher barrel temperatures and screw speed.

show abstract

“…In this modeling approach, momentum, continuity, and energy equations are solved to model the fluid flow. Pricci et al studied the process variables, such as mass flow rate, melting profile, and pressure profile, in the pellet-based additive manufacturing process [24]. The objective of this study was to determine the screw velocity to control the desired mass flow rate.…”

Section: Introductionmentioning

confidence: 99%

“…Pricci et al have proposed a mathematical model to describe the process from solid pellets to melt. The mathematical approach has been validated with numerical simulation and an experimental study [24]. Their numerical simulation is based on the CFD approach.…”

Section: Introductionmentioning

confidence: 99%

An Investigation of the Influence of Viscosity and Printing Parameters on the Extrudate Geometry in the Material Extrusion Process

et al. 2023

View full text Add to dashboard Cite

The material extrusion process is one of the most popular additive manufacturing processes. The presence of porosity in the MEX printed parts, which ultimately deteriorates the mechanical properties, is one of the main drawbacks of the MEX process. The porosity in the structure is related to the shape of the adjacent beads and overlapping during the material deposition. Due to the deposition nature of the MEX process, the porosity cannot be entirely removed from the printed parts. Understanding the influence of process parameters on material deposition and the rheological properties is crucial to improving the quality of the final product. In this study, the two-phase-flow numerical approach with the level-set equations has been used for the first time to model the material deposition on the moving platform in 3D. The influence of the viscosity and printing parameters, including travel speed, inlet velocity, viscosity, nozzle diameter, and layer height, on the width of the deposited bead has been investigated. The simulation results are validated against experimental measurements with an average error of 5.92%. The width measured by the experimental study shows good agreement with the results of the numerical simulation. The comparison between the results of the 3D numerical simulation and 2D simulation reveals that the 2D simulation is not appropriate and accurate enough to predict the geometry of the deposited bead with the given set of parameter settings. The key novelty of this research paper is the application of the level-set method in a 3D context for material deposition on a moving substrate.

show abstract

Modeling of extrusion-based additive manufacturing for pelletized thermoplastics: Analytical relationships between process parameters and extrusion outcomes

Cited by 6 publications

References 23 publications

Fiber Orientation Quantification for Large Area Additively Manufactured Parts Using SEM Imaging

Fiber Orientation Quantification for Large Area Additively Manufactured Parts Using SEM Imaging

Non-Newtonian, non-isothermal three-dimensional modeling of strand deposition in screw-based material extrusion

An Investigation of the Influence of Viscosity and Printing Parameters on the Extrudate Geometry in the Material Extrusion Process

Contact Info

Product

Resources

About