How generalisable are material extrusion additive manufacturing parameter optimisation studies? A systematic review (original) (raw)
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Experimental Investigation of Filament Behaviour in Material Extrusion Additive Manufacturing
Industrializing Additive Manufacturing
Fused Deposition Modelling (FDM) is a relatively low-cost additive manufacturing process that is commonly characterised by poor dimensional accuracy and precision. Prior work indicates that dimensional errors may be the result of fundamental issues relating to how the filament behaves during deposition and not due to limitations in FDM machine design. Some studies have examined the cross-sectional area of single strands, highlighting the dimensional variation, but there have been no studies examining these changes in other orthogonal planes and along the whole strand length. This study seeks to characterise the behavior of deposited material, to explore the impact of different process parameters on single and multiple strand geometries. Single layer strands of Poly-Lactic Acid (PLA) are deposited through a 0.4 mm diameter nozzle at varying nozzle gap heights, filament volumetric velocities, and print head velocities. Image analysis is used to quantify the width, height, cross sectional shape, and qualitatively analyse strand geometries. Basic print repeatability is shown to be in the order of AE75 lm at a strand length of 20 mm. By altering processing parameters, strand width variation of 2.6 mm has been demonstrated. Variations at the start and end of each strand are more significant than in the middle. Variations in shape becomes much more pronounced when printing multiple strands on top of each other. These results demonstrate the importance of careful process parameter selection on part quality, which to date has not been sufficiently well acknowledged.
An Investigation on Selected Factors that Cause Variability in Additive Manufacturing
2018
Additive manufacturing (AM) brings significant freedom in design, yet it can get hard to produce the same part at identical dimensional tolerances; this is also known as the reproducibility problem. Reproducibility, the ability to produce the same part under similar conditions, is one of the major challenges in AM as reproducibility plays an important role in the replacement of worn-out or damaged parts in an assembly. The objective of this paper is to identify the impacts of two most common factors (i.e., layer thickness and printing speed) on the dimensional accuracy of additively manufactured parts through a designed experiment. A fullfactorial experimental design involving these factors at three levels is implemented to investigate them. We printed a dog bone testing specimen by using Poly Lactic Acid (PLA) polymer and Fused Filament Fabrication (FFF) technology. The dimensional properties of the parts are then measured to statistically compare the variability in each level to d...
Additive Manufacturing
The material extrusion process is investigated by focusing on the geometry of a single strand extruded through a printing nozzle and deposited on a substrate of a 3D printer. An experimental protocol is set to determine the width W , and the height H, of a strand. The geometry depends mainly on the nozzle diameter D, the gap between the substrate and the tip of the nozzle g, the extrusion velocity U and the printing velocity V. The relevant parameter to determine W/D and H/g is reduced to one dimensionless parameter equal to (D/g)(U/V). A computational multiphase flow is described using a level set approach and a finite element method. The heat transfer is also taken into account in the set of governing equations. The polymer is considered as a generalised Newtonian fluid. An accurate description of the interface between the polymer and the surrounding air is developed based on an anisotropic remeshing procedure. Two different situations are numerically solved for which: (i) a first case with a g/D ratio less than one and (ii) a second case with a g/D ratio larger than one. In the first situation, the spreading below the nozzle is more or less radial around the vertical axis of the extruder which is not the case in the second situation. The numerical shape geometry is in good agreement with experimental observations. The thermal cooling underlines that the relevant parameters are the perimeter and the area of the strand cross-section and the Péclet number based on the printing velocity. The numerical predictions of W/D and H/g agree with experimental results.
Study of Accuracy of Parts Produced Using Additive Manufacturing | NIST
2014
(NIST); not subject to copyright in the United States. The full descriptions of the procedures used in this paper require the identification of certain commercial products. The inclusion of such information should in no way be construed as indicating that such products are endorsed by NIST or are recommended by NIST or that they are necessarily the best materials, instruments, software or suppliers for the purposes described.
International journal of online and biomedical engineering, 2023
3D printers are known for providing parts with relatively good accuracy. However, the level of accuracy in the dimensions of printed objects may not matter if they do not have a mechanical purpose. When multiple 3D-printed parts are intended to be integrated with each other to create a larger system, even a fraction of a millimeter can have a significant impact on the entire system. This study aims to investigate the variation in dimension when a single print file is replicated using the same slicing settings. The findings are then analyzed using quality control tools and compared to the designed measurements. Fused deposition modeling (FDM) technology or fused filament fabrication (FFF) technology was chosen for this study due to its availability to the common user, its relatively low cost, and its increasing popularity in different applications and industries. The material used in this study is polylactic acid (PLA) which is a thermoplastic and the most widely used plastic filament in 3D printing. It has a low melting point, high strength, low thermal expansion, and is relatively cheap. The dimensional accuracy of FDM-produced parts was evaluated by comparing the dimensions of the fabricated specimens with their computer-aided design (CAD) models. Statistical analysis revealed that the mean dimensional deviations were within the specified tolerance limits for most of the tested parts. This suggests that FDM technology is reliable in terms of achieving dimensional accuracy. KEYWORDS 3D printed, FDM technology, FFF technology, accuracy of 3D printed parts, polylactic acid (PLA) 1 INTRODUCTION Additive manufacturing (AM), commonly known as 3D printing has revolutionized the manufacturing industry and had a huge impact on how various industries operate. Additive manufacturing has provided users with the freedom to design complex parts that are not easily manufactured using traditional manufacturing methods. This
International Journal of Advanced Technology and Engineering Exploration, 2022
Additive manufacturing (AM) technology is a new way of manufacturing components by depositing materials layer by layer according to a digital model. Since its birth in the 1980s, AM has offered new opportunities to manufacturers, and has given rise to new applications. Several three-dimensional (3D) processes exist, each having specific properties and different types of technology. While AM offers significant benefits, it also presents some challenges to designers that must be understood and addressed. This article reviews the advances in this field, the main processes studied or used, and their characteristics, including the main parameters influencing product quality. We summarize all the factors in fishbone diagrams for each AM family. Finally, some AF industrial applications were discussed with its use and contribution to the fight against COVID-19 during the pandemic.
Process Design and Parameters Interaction in Material Extrusion 3D Printing: A Review
Polymers
Additive Manufacturing (AM), commonly known as “3D printing”, is rapidly integrated into many various fields, from everyday commercial to high-end medical and aerospace. Its production flexibility in small-scale and complex shapes is a significant advantage over conventional methods. However, inferior physical properties of parts manufactured by AM in general, and by material extrusion in particular, compared to traditional fabrication methods, inhibit its full assimilation. Specifically, the mechanical properties of printed parts are not high enough and, more importantly, not consistent enough. Optimization of the many various printing parameters is therefore required. This work reviews the influence of material selection, printing parameters such as path (e.g., layer thickness and raster angle), build (e.g., infill and building orientation) and temperature parameters (e.g., nozzle or platform temperature) on mechanical properties. Moreover, this work focuses on the interactions be...
Despite significant advances and established advantages of material extrusion additive manufacturing, limitations still exist regarding ability to increase productivity and still maintain high shape fidelity and defect-free parts within the range of process parameter values that a 3D printer may support. In the present study a predictive process-planning tool to balance productivity and quality of fabricated parts according to user's requirements is developed. Taguchi design of experiments (DoE) method is employed in order to determine the process parameters that impact shape fidelity in terms of material deposition stability that results in surfaces of acceptable flatness and defect-free parts. The development of four well-documented fabrication defects is quantified by CAD-to-part 3D comparison. Then, Analysis of Variance (ANOVA) was performed to reveal, characteristically, that, even though reduced speed generally results in improved shape fidelity, defects arise when small layer thickness is also set. On the other hand, increased layer thickness may be coupled with moderate material deposition speed to improve process productivity without sacrificing part shape. A highly reliable Artificial Neural Network (ANN) is constructed in an optimum way, and trained on the previous experiments with the aim to predict shape fidelity across the entire factor level range. Hence, material flow rate which is a function of investigated factors is provided with direct feedback by the ANN regarding possible defects or deteriorated part shape. The method presented lays the basis for robust process optimization on any 3D printer.
Journal of Engineering Science and Technology (JESTEC), 2023
3D printing technology, also known as additive manufacturing, is one of the prototyping systems for creating 3-dimensional models (prototypes). One of the most frequently used techniques is FDM (Fused Deposition Modelling) due to its simple working principle of melting the filament material and then extruding it. However, the price of filament used in 3D printing is still quite expensive, especially filaments with a mixture of metals. This study attempts to fabricate filament made of PLA and brass using a self-made extruder machine. The success criteria are determined by the precision of the filament and its strength. The accuracy of the printed filament was measured using a 0.01 mm micrometre, while strength was measured using the pull-out test. Three parameters were used: barrel temperature, material composition and roller speed, with two levels each. Taguchi L4(23) was used to design the experiments, followed by S/N ratio analysis and ANOVA. The results showed that on the dimensional accuracy, the influential parameters were temperature and roller speed, for the optimal parameter level at a temperature of 95oC, composition 10/30 g, and roller speed 3.02 mm/s. As for the single filament tensile test, the parameters that affect it are temperature and composition. For the optimal parameter level at a temperature of 100oC, the composition is 10/30 g, and the roller speed is 2.70 mm/s.
Analysis of the factors affecting the dimensional accuracy of 3D printed products
Materials Today: Proceedings, 2018
3D printing or additive manufacturing is a process in which objects are made by adding material instead of removing it. It is printed layer by layer in a machine known as 3D printer which uses the digital file to convert the virtual design of the object to a real one. Its scope as a manufacturing process is increasing rapidly and has the potential to replace conventional manufacturing processes. The focus now shifts to make it the primary manufacturing process and for this the most important point to look upon is the accuracy of 3D printed products. This research works intend's to study the factors which effect's the dimensional accuracy of the parts produced by 3D printing. Fused Deposition Modelling (FDM) is the method that is used in this study and the material used is Polylactic acid (PLA) filament. Factors which are observed are the effect of orientation, i.e. the effect of gravity on the accuracy of 3D printed products, and the effect of support which shows how the accuracy can differ when the support feature is enabled.