Characterization of Material Behavior of the Fused Deposition Modeling Processed Parts

2017 ◽  
Author(s):  
Madhukar Somireddy ◽  
Aleksander Czekanski
Keyword(s):  
Finite Element ◽  
Elastic Moduli ◽  
Fused Deposition Modeling ◽  
Material Behavior ◽  
Constitutive Law ◽  
Finite Element Models ◽  
Strength Parameters ◽  
Fused Deposition ◽  
Deposition Modeling

In the present research, one of the additive manufacturing techniques, fused deposition modeling (FDM) fabricated parts are considered for investigation of their material behavior. The FDM process is a layer upon layer deposition of a material to build three dimensional parts and such parts behave as laminated composite structures. Each layer of the part acts as a unidirectional fiber reinforced lamina, which is treated as an orthotropic material. The mesostructure of a part fabricated via fused deposition modeling process is accounted for in the investigation of its mechanical behavior. The finite element (FE) procedure for characterization of a material constitutive law for the FDM processed parts is presented. In the analysis, the mesostructure of the part obtained via FDM process is replicated in the finite element models. Finite element models of tensile specimens are developed with mesostructure that would be obtained from FDM process, then uniaxial tensile test simulations are conducted. The elastic moduli of a lamina are calculated from the linear analysis and the strength parameters are obtained from the nonlinear finite element analysis. The present work provides a FE methodology to find elastic moduli and strength parameters of a FDM processed part by accounting its mesostructure in the analysis.

Mechanical characterization and finite element modeling of polylactic acid BCC-Z cellular lattice structures fabricated by fused deposition modeling

2016 ◽  
Vol 231 (11) ◽  
pp. 1995-2004 ◽  
Author(s):  
R Rezaei ◽  
MR Karamooz Ravari ◽  
M Badrossamay ◽  
M Kadkhodaei
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Polylactic Acid ◽  
Fused Deposition Modeling ◽  
Material Behavior ◽  
Lattice Structures ◽  
Stress Strain ◽  
Fused Deposition ◽  
Tension And Compression ◽  
Deposition Modeling

In recent years, cellular lattice structures are of interest due to their high strength in combination with low weight. They may be used in various areas such as aerospace and automotive industries. Accordingly, assessment of their manufacturability, repeatability and mechanical properties is very important. In this paper, these issues are investigated for Polylactic Acid cellular lattice structures fabricated by fused deposition modeling. To do so, some benchmarks are designed and fabricated to find suitable processing parameters as well as the structural dimensions. In addition, to evaluate the mechanical properties of the lattice’s material, a number of tension and compression specimens are fabricated and tested. The material’s stress–strain curves reveal non-linear behaviors. These curves are not coincided in tension and compression which shows an asymmetric material behavior. To characterize the fabricated cellular lattices, they are tested in compression, and the deformation mechanisms of the structures are analyzed. To investigate the correlation between the bulk material and the material of the ligaments, a solid finite element model is developed to predict the stress–strain response of the lattice. The obtained result shows a reasonably good correlation between the model and experiments.

scholarly journals Design and Characterization of a Screw Extrusion Hot-End for Fused Deposition Modeling

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 590
Author(s):  
Tim Feuerbach ◽  
Markus Thommes
Keyword(s):  
Vinyl Acetate ◽  
Fused Deposition Modeling ◽  
Ethylene Vinyl Acetate ◽  
Direct Printing ◽  
Fused Deposition ◽  
Screw Extrusion ◽  
Deposition Modeling ◽  
Feedstock Material ◽  
Material Form

The filament is the most widespread feedstock material form used for fused deposition modeling printers. Filaments must be manufactured with tight dimensional tolerances, both to be processable in the hot-end and to obtain printed objects of high quality. The ability to successfully feed the filament into the printer is also related to the mechanical properties of the filament, which are often insufficient for pharmaceutically relevant excipients. In the scope of this work, an 8 mm single screw hot-end was designed and characterized, which allows direct printing of materials from their powder form and does not require an intermediate filament. The capability of the hot-end to increase the range of applicable excipients to fused deposition modeling was demonstrated by processing and printing several excipients that are not suitable for fused deposition modeling in their filament forms, such as ethylene vinyl acetate and poly(1-vinylpyrrolidone-co-vinyl acetate). The conveying characteristic of the screw was investigated experimentally with all materials and was in agreement with an established model from literature. The complete design information, such as the screw geometry and the hot-end dimensions, is provided in this work.

scholarly journals Automated Testing and Characterization of Additive Manufacturing (ATCAM)

2021 ◽  
Author(s):  
Arash Alex Mazhari ◽  
Randall Ticknor ◽  
Sean Swei ◽  
Stanley Krzesniak ◽  
Mircea Teodorescu
Keyword(s):  
Additive Manufacturing ◽  
Fused Deposition Modeling ◽  
Cell System ◽  
Automated Testing ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
Machine Calibration

AbstractThe sensitivity of additive manufacturing (AM) to the variability of feedstock quality, machine calibration, and accuracy drives the need for frequent characterization of fabricated objects for a robust material process. The constant testing is fiscally and logistically intensive, often requiring coupons that are manufactured and tested in independent facilities. As a step toward integrating testing and characterization into the AM process while reducing cost, we propose the automated testing and characterization of AM (ATCAM). ATCAM is configured for fused deposition modeling (FDM) and introduces the concept of dynamic coupons to generate large quantities of basic AM samples. An in situ actuator is printed on the build surface to deploy coupons through impact, which is sensed by a load cell system utilizing machine learning (ML) to correlate AM data. We test ATCAM’s ability to distinguish the quality of three PLA feedstock at differing price points by generating and comparing 3000 dynamic coupons in 10 repetitions of 100 coupon cycles per material. ATCAM correlated the quality of each feedstock and visualized fatigue of in situ actuators over each testing cycle. Three ML algorithms were then compared, with Gradient Boost regression demonstrating a 71% correlation of dynamic coupons to their parent feedstock and provided confidence for the quality of AM data ATCAM generates.

Fracture assessment of polycarbonate parts produced by fused deposition modeling in the out-of-plane printing direction – effect of raster angle

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Iman Sedighi ◽  
Majid R. Ayatollahi ◽  
Bahador Bahrami ◽  
Marco A. Pérez-Martínez ◽  
Andrés A. Garcia-Granada
Keyword(s):  
Fracture Toughness ◽  
Finite Element ◽  
Fracture Behavior ◽  
Fused Deposition Modeling ◽  
Mode I ◽  
Content Type ◽  
Fused Deposition ◽  
Out Of Plane ◽  
Deposition Modeling ◽  
Fracture Tests

Purpose The purpose of this paper is to study the Mode I fracture behavior of polycarbonate (PC) parts produced using fused deposition modeling (FDM). The focus of this study is on samples printed along the out-of-plane direction with different raster angles. Design/methodology/approach Tensile and Mode I fracture tests were conducted. Semi-circular bend specimens were used for the fracture tests, which were printed in four different raster patterns of (0/90), (15/−75) (30/−60) and (45/−45). Moreover, the finite element method (FEM) was used to determine the applicability of linear elastic fracture mechanics (LEFM) for the printed PC parts. The fracture toughness results, as well as the fracture path and the fracture surfaces, were studied to describe the fracture behavior of the samples. Findings Finite element results confirm that the use of LEFM is allowed for the tested PC samples. The fracture toughness results show that changing the direction of the printed rasters can have an effect of up to 50% on the fracture toughness of the printed parts, with the (+45/−45) and (0/90) orientations having the highest and lowest resistance to crack propagation, respectively. Moreover, except for the (0/90) orientation, the other samples have higher crack resistance compared to the bulk material. The fracture toughness of the tested PC depends more on the toughness of the printed sample, rather than its tensile strength. Originality/value The toughness and the energy absorption capability of the printed samples (with different raster patterns) were identified as the main properties affecting the fracture toughness of the AM PC parts. Because the fracture resistance of almost all the samples was higher than that of the base material, it is evident that by choosing the right raster patterns for 3D-printed parts, very high resistance to crack growth may be obtained. Also, using FEM and comparing the size of the plastic zones, it was concluded that, although the tensile curves show nonlinearity, LEFM is still applicable for the printed parts.

Simulation of edge quality in fused deposition modeling

2019 ◽  
Vol 25 (3) ◽  
pp. 541-554 ◽  
Author(s):  
Antonio Armillotta
Keyword(s):  
Fused Deposition Modeling ◽  
Experimental Tests ◽  
Geometric Errors ◽  
Content Type ◽  
Fused Deposition ◽  
Graphical Simulation ◽  
Deposition Modeling ◽  
Edge Quality ◽  
Input Variables

Purpose The purpose of this paper is to propose a method for simulating the profile of part edges as a result of the FDM process. Deviations from nominal edge shape are predicted as a function of the layer thickness and three characteristic angles depending on part geometry and build orientation. Design/methodology/approach Typical patterns of edge profiles were observed on sample FDM parts and interpreted as the effects of possible toolpath generation strategies. An algorithm was developed to generate edge profiles consistent with the patterns expected for any combination of input variables. Findings Experimental tests confirmed that the simulation procedure can correctly predict basic geometric properties of edge profiles such as frequency, amplitude and shape of periodic asperities. Research limitations/implications The algorithm takes into account only a subset of the error causes recognized in previous studies. Additional causes could be integrated in the simulation to improve the estimation of geometric errors. Practical implications Edge simulation may help avoid process choices that result in aesthetic and functional defects on FDM parts. Originality/value Compared to the statistical estimation of geometric errors, graphical simulation allows a more detailed characterization of edge quality and a better diagnosis of error causes.

scholarly journals Fully resolved numerical simulations of fused deposition modeling. Part II – solidification, residual stresses and modeling of the nozzle

2018 ◽  
Vol 24 (6) ◽  
pp. 973-987 ◽  
Author(s):  
Huanxiong Xia ◽  
Jiacai Lu ◽  
Gretar Tryggvason
Keyword(s):  
Residual Stresses ◽  
Numerical Simulations ◽  
Fused Deposition Modeling ◽  
Fixed Bed ◽  
Ground Truth ◽  
Deposition Process ◽  
Material Behavior ◽  
Content Type ◽  
Fused Deposition ◽  
Deposition Modeling

Purpose The purpose of this paper is to continue to describe the development of a comprehensive methodology for fully resolved numerical simulations of fused deposition modeling. Design/methodology/approach A front-tracking/finite volume method introduced in Part I to simulate the heat transfer and fluid dynamics of the deposition of a polymer filament on a fixed bed is extended by adding an improved model for the injection nozzle, including the shrinkage of the polymer as it cools down, and accounting for stresses in the solid. Findings The accuracy and convergence properties of the new method are tested by grid refinement, and the method is shown to produce convergent solutions for the shape of the filament, the temperature distribution, the shrinkage and the solid stresses. Research limitations/implications The method presented in the paper focuses on modeling the fluid flow, the cooling and solidification and volume changes and residual stresses, using a relatively simple viscoelastic constitutive model. More complex material models, depending, for example, on the evolution of the conformation tensor, are not included. Practical implications The ability to carry out fully resolved numerical simulations of the fused deposition process is expected to be critical for the validation of mathematical models for the material behavior, to help explore new deposition strategies and to provide the “ground truth” for the development of reduced-order models. Originality/value The paper completes describing the development of the first numerical method for fully resolved simulation of fused filament modeling.

scholarly journals Characterization of chemical contaminants generated by a desktop fused deposition modeling 3-dimensional Printer

2017 ◽  
Vol 14 (7) ◽  
pp. 540-550 ◽  
Author(s):  
Aleksandr B. Stefaniak ◽  
Ryan F. LeBouf ◽  
Jinghai Yi ◽  
Jason Ham ◽  
Timothy Nurkewicz ◽  
...  
Keyword(s):  
Fused Deposition Modeling ◽  
Chemical Contaminants ◽  
3 Dimensional ◽  
Fused Deposition ◽  
Deposition Modeling

scholarly journals Basic Research for Additive Manufacturing of Rubber

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2266 ◽  
Author(s):  
Welf-Guntram Drossel ◽  
Jörn Ihlemann ◽  
Ralf Landgraf ◽  
Erik Oelsch ◽  
Marek Schmidt
Keyword(s):  
Fused Deposition Modeling ◽  
Basic Research ◽  
Traverse Speed ◽  
Material Behavior ◽  
Technical Solution ◽  
Fused Deposition ◽  
Optimum Parameters ◽  
Printing Quality ◽  
Deposition Modeling ◽  
Printing Parameters

The dissemination and use of additive processes are growing rapidly. Nevertheless, for the material class of elastomers made of vulcanizable rubber, there is still no technical solution for producing them using 3D printing. Therefore, this paper deals with the basic investigations to develop an approach for rubber printing. For this purpose, a fused deposition modeling (FDM) 3D printer is modified with a screw extruder. Tests are carried out to identify the optimal printing parameters. Afterwards, test prints are performed for the deposition of rubber strands on top of each other and for the fabrication of simple two-dimensional geometries. The material behavior during printing, the printing quality as well as occurrences of deviations in the geometries are evaluated. The results show that the realization of 3D rubber printing is possible. However, there is still a need for research to stabilize the layers during the printing process. Additionally, further studies are necessary to determine the optimum parameters for traverse speed and material discharge, especially on contours.

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