Fused filament fabrication: comparison of methods for determining the interfacial strength of single welded tracks

Heuer, Anselm; Huether, Jonas; Liebig, Wilfried V.; Elsner, Peter

doi:10.1051/mfreview/2021031

Cited by 3 publications

(1 citation statement)

References 27 publications

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“…Usually, this process can create porous structures through gaps between the tracks, but this results in a coarsely distributed porosity, and the amount of welded joints between the tracks decreases. However, these welded joints have a large influence on the mechanical properties in addition to the general reduction in mechanical properties due to increased porosity [8,9]. Thus, increasing the porosity without reducing the amount of welded joints would be an attractive approach for producing porous structures for lightweight applications.…”

Section: Introductionmentioning

confidence: 99%

On the Creation and Optical Microstructure Characterisation of Additively Manufactured Foam Structures (AMF)

Heuer,

Rees,

Weidenmann

et al. 2023

Polymers

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Plastic-based additive manufacturing processes are becoming increasingly popular in the production of structural parts. Based on the idea of lightweight design and the aim of extending the functionality of additive structures, the production of additively manufactured foam structures has emerged as a new field of application. The optical characterisation of these structures is of particular importance for process adjustments and the identification of (unwanted) changes in the foam structure. The degree of foaming and the fineness of a foam structure are of interest at this point. In this context, only the part of a structure dominated by foam pores is considered a foam structure. So far, there are no sophisticated methods for such an optical characterisation. Therefore, in this work, microscope images of manufactured as well as artificially created additively manufactured foam structures were evaluated. On these images, the features porosity, pore size, pore amount and a measure for the textural change were determined in order to obtain information about changes within an additively manufactured foam structure. It is shown that additive structures show changing pore shapes depending on the orientation of the cutting plane, although there are no changes in the foaming behaviour. Therefore, caution is required when identifying changes within the foam structure. It was also found that, owing to the additive process, the total porosity is already set in the slicing process and remains constant even if the degree of foaming of individual tracks is changed. Therefore, the degree of foaming cannot be determined on the basis of the total porosity, but it can be assessed on the basis of the formation of large networks of process-related pores.

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Section: Introductionmentioning

confidence: 99%

On the Creation and Optical Microstructure Characterisation of Additively Manufactured Foam Structures (AMF)

Heuer,

Rees,

Weidenmann

et al. 2023

Polymers

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Evaluation of mechanical properties characterization of additively manufactured components

Frölich,

Bechtloff,

Scheuring

et al. 2024

Prog Addit Manuf

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Additive manufacturing by material extrusion offers innovative potential for component design and is driving advances in many industries. However, fully harnessing these advancements necessitates a thorough comprehension of the process-specific anisotropic structural properties. The complex interactions between process parameters and their direct influence on structural properties often lead to discrepancies between the mechanical properties of tested specimens at the coupon level and the inherent properties of additively manufactured components. In addition, there is no standardized method for preparing specimens that represent the mechanical properties within a given component. This further complicates the comparison of measured properties of different series of measurements and the investigation of manufacturing effects that may occur during the production of a component. Given these challenges, the present work addresses the fundamental question of what aspects need to be considered to ensure that the test specimens reflect the process conditions being tested. The studies look at the requirements for producing representative specimens and for the test methodology to characterize the mechanical properties of additively manufactured structures. The tests are carried out on specimens that were produced directly using the material extrusion process and on specimens that were cut from additively manufactured plates. Water jet cutting, milling, and laser cutting are investigated and compared as cutting methods. The influence of the specimen geometry and the size of the additively manufactured plate is considered. The orientation-dependent mechanical properties, the significance of the individual tests, the measurement scatter, and scanning electron micrographs of the cut edges and fracture surfaces are analyzed. Finally, guidelines for performing representative tests to characterize the mechanical properties of additively manufactured components are proposed.

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Phase-field modeling of the morphological and thermal evolution of additively manufactured polylactic acid layers and their influence on the effective elastic mechanical properties

Elmoghazy,

Heuer,

Kneer

et al. 2024

Prog Addit Manuf

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This study presents a comprehensive simulation of the fused deposition modeling (FFF) process of polylactic acid (PLA) using the multiphase-field method. Compared to existing works, this work aims to simulate the overall FFF process. It combines temperature evolution, viscous flow, polymer crystallization, and residual strain calculations within the microstructure with mechanical property analysis in a single study. Simulation studies were done in the case of the single layer to study the flowing effect of the filament and the distribution of temperature, viscosity, and relative crystallinity throughout the cooling process. Afterward, a system of layers with three rows and three columns was investigated. The nozzle temperature, bed temperature, viscosity, and layer height were varied, and for each case the porosity was calculated. After running mechanical loading simulations on each case, the effective Young’s modulus was calculated. The simulations show that increasing the nozzle and bed temperatures leads to a decrease in the porosity, while increasing the layer height increases the distortion in the pores’ shapes without significantly affecting the porosity. The decrease in porosity leads to an increase in the effective Young’s modulus of the structure in a linear trend within the investigated porosities. The Young’s modulus–porosity relation was validated with experimental values from the literature within an average error of 3.6 %.

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Fused filament fabrication: comparison of methods for determining the interfacial strength of single welded tracks

Cited by 3 publications

References 27 publications

On the Creation and Optical Microstructure Characterisation of Additively Manufactured Foam Structures (AMF)

On the Creation and Optical Microstructure Characterisation of Additively Manufactured Foam Structures (AMF)

Evaluation of mechanical properties characterization of additively manufactured components

Phase-field modeling of the morphological and thermal evolution of additively manufactured polylactic acid layers and their influence on the effective elastic mechanical properties

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