Nozzle-integrated pre-deposition and post-deposition heating of previously deposited layers in polymer extrusion based additive manufacturing

Ravoori, Darshan; Prajapati, Hardikkumar; Talluru, Viswajit; Adnan, Ashfaq; Jain, Ankur

doi:10.1016/j.addma.2019.06.006

Cited by 25 publications

(11 citation statements)

References 23 publications

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“…Edwards and Mackay [65] also developed a post-extrusion heating model for both amorphous and semi-crystalline polymers to minimize the formation of "shark-skin" defects during MatEx. Key works that account for radiative heat transfer effects have shown excellent agreement between the temperature profile in the nozzle prior to and after deposition [66], in the standoff region (between nozzle & bed) [67], and on the print bed [45].…”

Section: Heat Transfermentioning

confidence: 96%

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

2020

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Material-extrusion (MatEx) additive manufacturing involves layer-by-layer assembly of extruded material onto a printer bed and has found applications in rapid prototyping. Both material and machining limitations lead to poor mechanical properties of printed parts. Such problems may be addressed via an improved understanding of the complex transport processes and multiphysics associated with the MatEx process. Thereby, this review paper describes the current (last 5 years) state of the art modeling approaches based on momentum, heat and mass transfer that are employed in an effort to achieve this understanding. We describe how specific details regarding polymer chain orientation, viscoelastic behavior and crystallization are often neglected and demonstrate that there is a key need to couple the transport phenomena. Such a combined modeling approach can expand MatEx applicability to broader application space, thus we present prospective avenues to provide more comprehensive modeling and therefore new insights into enhancing MatEx performance.

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Section: Heat Transfermentioning

confidence: 96%

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

2020

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“…Meanwhile, the radiant heat transfer between the hot-end and printed part is also ignored for now (despite that Thézé et al [34] suggested otherwise), since it can only contribute to a reheating in the surface temperature by no more than 5 °C [34,35]. When there are no additional external/internal heat sources for pre/post-heating [36][37][38][39], the only mechanism retained is the radiant heat transfer between the printed part and the far environment.…”

Section: Hypothesesmentioning

confidence: 99%

T4F3: temperature for fused filament fabrication

2022

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Temperature fields and their variations in printed parts are the basis for understanding the physical process of fused filament fabrication (FFF). However, reliable temperature data are still rather limited to date. This article presents a three-dimensional transient-state model to simulate the temporal and spatial temperature variations in FFF printed parts. Model variables range from geometry dimensions and (dynamic) material properties to process parameters, covering all important physical phenomena, including conduction anisotropy and radiant heat transfer. The validation of the model is performed against six sets of experimental temperature data obtained with different geometries, machines, materials, processes, temperature measuring methods, etc. Insights in the thermal process are also reported. For example, the heat penetration depth in printing with poly(lactic acid) is limited to 3 mm, and the Biot number intimately characterises the reheating peaks in temporal profiles. This model shows the potential to become a standardised tool to study the thermal characteristics of FFF printed parts. It is made openly available on website https://iiw.kuleuven.be/onderzoek/aml/technologyoffer. Graphic abstract

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“…An optimized local temperature management allows for an improvement of the adhesive (polymer layer to substrate) and cohesive (layer to layer) properties [ 5 , 6 , 7 , 13 , 14 , 15 , 17 , 18 , 19 , 20 ]. Thermography is suitable to evaluate the ME process in terms of local temperature distribution [ 18 , 19 , 21 , 22 ].…”

Section: Introductionmentioning

confidence: 99%

Estimation of the Adhesion Interface Performance in Aluminum-PLA Joints by Thermographic Monitoring of the Material Extrusion Process

et al. 2020

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Using additive manufacturing to generate a polymer–metal structure offers the potential to achieve a complex customized polymer structure joined to a metal base of high stiffness and strength. A tool to evaluate the generated interface during the process is of fundamental interest, as the sequential deposition of the polymer as well as temperature gradients within the substrate lead to local variations in adhesion depending on the local processing conditions. On preheated aluminum substrates, 0.3 and 0.6 mm high traces of polylactic acid (PLA) were deposited. Based on differential scanning calorimetry (DSC) and rheometry measurements, the substrate temperature was varied in between 150 and 200 °C to identify an optimized manufacturing process. Decreasing the layer height and increasing the substrate temperature promoted wetting and improved the adhesion interface performance as measured in a single lap shear test (up to 7 MPa). Thermographic monitoring was conducted at an angle of 25° with respect to the substrate surface and allowed a thermal evaluation of the process at any position on the substrate. Based on the thermographic information acquired during the first second after extrusion and the preset shape of the polymer trace, the resulting wetting and shear strength were estimated.

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Nozzle-integrated pre-deposition and post-deposition heating of previously deposited layers in polymer extrusion based additive manufacturing

Cited by 25 publications

References 23 publications

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

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

T4F3: temperature for fused filament fabrication

Estimation of the Adhesion Interface Performance in Aluminum-PLA Joints by Thermographic Monitoring of the Material Extrusion Process

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