Fused Deposition Modeling Additive Manufacturing Research Articles

Experimental study of the fracture of CT specimens printed in PLA as a function of the raster width

The FDM (Fused Deposition Modelling) additive manufacturing process is characterised by a large number of process variables that determine the mechanical properties and quality of the manufactured parts. When printing layer by layer, the filaments constituting the layer are welded on the one hand between them in the same layer and on the other hand between the superimposed layers, this welding develops on the contact surfaces (raster width) along the deposited filaments. The quality of this welding determines the resistance to crack propagation between filaments and between layers. This article aims to study the effect of the width of the raster on the resistance to crack propagation in a structure obtained by FDM.We have developed an experimental approach from CT specimens to determine the tensile strength of polylactic acid (PLA) polymers, considering the J-Integral method. And given the complexity of the problem, three cases of raster width (l=0.42 mm, l=0.56 mm and l=0.68 mm) have been treated.According to the results obtained (J, ∆a), the resistance to crack propagation in the parts printed by FDM seems to be better when the width of the filament is small. Indeed, the energy necessary to break the specimen is relatively greater than in the case of a larger width. This finding was confirmed by comparing the values of J for a given advancement of the crack for the three cases studied.In order to present an exhaustive study, we focused on the effect of raster widths (including 0.42 mm, 0.56 mm to 0.68 mm) on the crack propagation of printed PLA. This study is in progress for other printing parameters. To highlight the cracking mechanisms, microscopic observations will be developed in greater depth at the SEM.Our analysis can be used as decision support in the design of FDM parts. In effect, we can choose the raster width that would provide the resistance to crack propagation desired for a functional part.In this article, we analysed the damage mechanism of CT specimens printed by FDM. This subject represents a new direction for many lines of research. For our study, we used the J-Integral theoretical approach to study the fracture behaviour of these parts by determining the resistance curves (J-∆a).

Mechanical properties and numerical simulation of FDM 3D printed PETG/carbon composite unit structures

Carbon fibers (CFs) were used as reinforcement in developing a polyethylene terephthalate glycol (PETG)-based polymer composite using the fused deposition modeling (FDM) 3D printing technique. The influence of CF and process factors (infill percentage, layer thickness, infill pattern) were studied by measuring the prepared polymer composite's tensile, flexural, and compressive properties. The innovative work that was carried out for this study and the tests that were performed revealed that it is difficult to predict the position of the specimen break area before a test. The PETG-reinforced polymer only showed enhanced flexural and tensile strength at a layer thickness of 0.25 mm and a maximum infill percentage of 20% for a solid structural design. Compressive strength improved in reinforced PETG hexagonal and circle structures. The confirmation of the numerical modeling applied to determine the mechanical properties of PETG for FDM additive manufacturing is one of the goals suggested in this research, along with a comparison of experimental and computational data. Scanning electron microscopy examination of the fractured sample surfaces revealed various fracture mechanisms and morphologies for the materials tested. The research found that the 3D-printed composite could further expand the application of PETG as an engineering material.

Additive Manufacturing of Linear Continuous Permittivity Profiles and Their Application to Cylindrical Dielectric Resonator Antennas

The utilization of additive manufacturing (AM) to engineer the permittivity profile of dielectric resonator antennas (DRAs) is considered. For the first time, the capabilities of AM are exploited to create continuously swept permittivity profiles and applied to cylindrical DRAs. The spatial variant lattices (SVL) synthesis algorithm is implemented to create the desired permittivity profiles from a single material, and resulting geometries are manufactured using a high-permittivity material in a fused deposition modeling AM process. Three individual antennas for global navigation satellite system bands are designed and manufactured, two inhomogeneous DRAs with continuous permittivity profiles along the radial and vertical axis, and one homogeneous DRA for comparison. The manufactured antennas are characterized by impedance, realized gain, and axial ratio. Experimental results agree well with simulations and show increased impedance-, gain-, and axial-ratio bandwidths for both inhomogeneous antennas compared to the homogeneous one.

Mechanical Properties of Fused Deposition Modeling of Polyetheretherketone (PEEK) and Interest for Dental Restorations: A Systematic Review.

The aim of this systematic review was to determine the optimal printing parameters for the producing of fused deposition modeling (FDM) 3D-printed polyetheretherketone (PEEK) elements with mechanical properties suitable for dental restorations. Indeed, the mechanical properties are a critical prerequisite for the study of other parameters, such as physical, aesthetic and biological properties. An exhaustive electronic search was carried out in the PubMed, Embase and Web of knowledge databases to gather all the studies evaluating the influence of the printing parameters on the obtained mechanical properties of FDM 3D-printed PEEK elements were selected. Initially, the search resulted in 614 eligible papers. Independent screenings of the abstracts were performed by two authors to identify the articles related to the question. Twenty-nine studies were selected, of which eleven were further excluded after reading of the full text, and finally, eighteen articles were included in this review. The studies were difficult to compare due to the variability of the printing parameters and the types of PEEK. However, it seems interesting to use a high infill rate, a high chamber temperature close to that of the printing temperature and a heat post-treatment to obtain 3D PEEK elements presenting properties adapted to use as dental restorations. The analysis of the available literature suggested that the properties of PEEK could make it an interesting material in dental restorations to be performed with FDM additive manufacturing.

Optimisation of the additive manufacturing parameters of polylactic acid (PLA) cellular structures for biomedical applications

Fused deposition modelling (FDM) is an additive manufacturing technology used to create functional and complex geometries directly from computer-generated models. This technique can be utilised to generate cellular structures with controllable pore size, pore shape, and porosity. Cellular structures are fundamental in orthopaedics scaffolds because of its low elastic modulus, high compressive strength, and adequate cell accommodation spaces. This paper aims at investigating and optimising the FDM additive manufacturing process parameters of polylactic Acid (PLA) for two lattice structures namely Schoen Gyroid and Schwarz Primitive. The effect of additive manufacturing critical process parameters including layer height, flow rate, and print speed on the geometrical accuracy and compressive strength of the specimens were analysed. In addition, other parameters that have minimal effect on the geometrical accuracy of the printed parts were discussed. A Full Factorial Analysis (FFA) using Minitab software was undertaken to identify the perfect combination of printing parameters to provide the most geometrically accurate structure. In this study, samples of the Schoen Gyroid and the Schwarz Primitive lattices and a solid control cylinder were 3D printed using the ideal printing combination to assess the manufacturability, the geometrical accuracy, and the mechanical behaviour of both designs. It was found that the optimised FDM process parameters for the studied cellular structures were a layer height of 0.16 mm, a printing speed of 50 mm/s and a flow rate of 90%. As a result of using these parameters, the solid, Schoen Gyroid and Schwarz Primitive specimens demonstrated elastic moduli values of 951 MPa, 264 MPa, and 221 MPa, respectively. In addition, the Schoen Gyroid and the Schwarz Primitive have reached their stress limits at around 8.68 MPa and 7.06 MPa, respectively. It was noticed that the Schoen Gyroid structure exhibited ∼ 18% higher compressive strength and ∼ 16% higher elastic modulus compared to the Schwarz Primitive structure for the same volume fraction of porosity, overall dimensions, and the manufacturing process parameters. Although both structures revealed mechanical properties that fall within the range of the human trabecular bone, but Schoen Gyroid exhibited improved structural integrity performance that is evident by its post-yield behaviour.

Influence of 3D Printing Parameters on Mechanical Properties of the PLA Parts Made by FDM Additive Manufacturing Process

Paper presents the results of factorial experiments made to establish the influence of technological parameters of 3D printing using the Fused Deposition Modeling (FDM) Technology, on the mechanical properties of the material deposited with ULTRA PLA filaments. By planning the experiments and the statistical processing of the results, mathematical relations were established regarding the dependence between the objective functions, the controllable factors and their interactions. To obtain high tensile strengths of the components made by 3D printing, regimes are required to allow the deposition of layers as thin as possible (h = 0.1 mm) and temperatures as high as possible, close to 300°C. The choice of inappropriate values of these process parameters can lead to a significant decrease in tensile strength, reaching even up to 30-40% of the maximum possible value to be reached. The experiments reveal that the printing speed does not have a major influence on the mechanical properties. Practical, the printing speed is limited by the technical characteristics of the printer used. The results of the experimental research obtained on a number of 30 process variants led to the establishment of optimal 3D printing variants that correspond to the requirements imposed on the objectively analysed functions (tensile strength, dimensional accuracy, speed of execution, surface quality).

Experimental Analysis on 3d Printed Onyx Specimens with Honeycomb Infill Structure

There is a demand for the development of products in a shorter time that resulted in the introduction of 3D printing which is also termed as “Additive Manufacturing” (AM). This technology has many advantages such as costeffectiveness, less manufacturing time and elimination of post-processing costs. Intensive research is being carried out on cellular structures manufactured using additive manufacturing technologies. Cellular structures have many applications in various areas. When compared to solid structures, these cellular structures possess high strength to weight ratio, good energy absorption characteristics, good thermal and acoustic insulation properties. They are used for aerospace, medical and engineering products. There are many additive manufacturing technologies whereas fused deposition modelling (FDM) is the most versatile one. This research consists of the analysis of hexagonal honeycomb structure by creating honeycomb structures of different dimensions in SolidWorks and manufacturing of those structures by using the FDM additive manufacturing process. These structures were designed by varying the internal hexagon’s wall thickness and side length. After printing these structures were subjected to Mechanical testings like tensile, compression, three-point bending, impact and thermal testing like heat deflection temperature tests. The three-point bending test was simulated numerically and compared with the experimental results. This study is finally validated by comparing experimental and simulation results, which were in agreement with each other. Experimental results show that the low-weight specimen exhibited good mechanical and thermal properties with a lesser printing time compared to the remaining specimens. The specimens with different hexagonal cell dimensions were introduced and discussed.

Parametric optimization of a cyclogiro aircraft design for efficient hover with aeroelastic considerations

A minimization procedure is proposed to orient the design of a vertical take-off and landing drone towards sustainability. The vehicle is a novel cycloidal rotor drone and the principal objective is to yield the best ratio of payload to power consumption. The drone blades, rotor arms, and frame are designed for fused deposition modeling additive manufacturing with polylactic acid. 10 variables for the geometry, operation parameters, and material infill percentages are explored in search of the optimum design. A special derivation procedure allows obtaining the symbolic equations for the weight and power consumption of the drone. This permits optimization with a hybrid genetic and gradient method and exploring a broad range of aircraft sizes. 7 constraint equations ensure that the necessary assumptions made for the derivation remain valid and that the structural strength is adequate. For each new configuration, this method allows to quickly find a new optimum design using a desktop computer. Also, modifying the constraints, variables, or objective function is straightforward. Finally, the resulting design has a power loading of 0.0876 N/W.

Multistable mechanical metamaterials with highly tunable strength and energy absorption performance

A novel multistable mechanical metamaterial showing highly tunable strength and energy absorption performance has been designed in this paper. A theoretical model is established to describe mechanical properties of the unit cell. The specimens of unit cells and metamaterials have been fabricated by fused deposition modeling additive manufacturing technology. Quasi-static compression and tensile experiments and the corresponding simulation analyses on these specimens are carried out. Results obtained from experiment and simulation methods demonstrate that mechanical properties of the presented bistable unit cell and multistable metamaterial can be tunable in a wide range with little change in total mass.

Extended CT Void Analysis in FDM Additive Manufacturing Components.

Additive manufacturing (AM) is the term for a number of processes for joining materials to build physical components from a digital 3D model. AM has multiple advantages over other construction techniques, such as freeform, customization, and waste reduction. However, AM components have been evaluated by destructive and non-destructive testing and have shown mechanical issues, such as reduced resistance, anisotropy and voids. The build direction affects the mechanical properties of the built part, including voids of different characteristics. The aim of this work is an extended analysis of void shape by means of X-ray computed tomography (CT) applied to fused deposition modeling (FDM) samples. Furthermore, a relation between the tensile mechanical properties and digital void measurements is established. The results of this work demonstrate that void characteristics such as quantity, size, sphericity and compactness show no obvious variations between the samples. However, the angle between the main void axis and the mechanical load axis α shows a relation for FDM components: when its mean value μ(α) is around 80 (degrees) the yield strength and Young’s modulus are reduced. These results lead to the formulation of a novel criterion that predicts the mechanical behavior of AM components.

Simulating cyber-physical systems: Identifying vulnerabilities for design and manufacturing through simulated additive manufacturing environments

Cyber-physical systems have been widely adopted in a number of industries, including healthcare, critical infrastructure, and manufacturing. The connectivity of machines, which characterizes cyber-physical systems and provides many of their benefits, leaves them vulnerable to cyber-attacks. Within manufacturing, cyber-attacks can compromise end-use parts, resulting in catastrophic part failure. Researchers have recently started to investigate the vulnerabilities within connected additive manufacturing machines, demonstrating vulnerabilities and proposing mitigation strategies. While informative, findings from past work are limited by the physical machines used in experiments, making results difficult to generalize to other systems. Further, physical experiments take time, waste stock material, and may not be generalizable for other machines. The goal of this work is to provide a digital testbed for future research to characterize the vulnerabilities of manufacturing CPS and develop new methods to effectively identify compromised parts. This paper proposes and validates an inexpensive and accessible simulation to accurately predict the physical output of a fused deposition modeling additive manufacturing machine. This simulation allows for efficient testing of attack vectors and determine the probability of attack detection using quality control methods. This study lays the groundwork for future research exploring the vulnerabilities in engineering design processes as manufacturers become increasingly reliant on connected production equipment.

Investigation on the static and dynamic behavior of BCC lattice structure with quatrefoil node manufactured using fused deposition modelling additive manufacturing

This paper presents a vibration characteristics of BCC lattice structure with quatrefoil node which has been made using the fused deposition modelling (FDM) additive manufacturing (AM) technique. By conducting vibration testing, the effect of strut diameter design parameter on the natural frequency values of the BCC lattice structure with quatrefoil node is investigated. The results showed that the natural frequency values of the lattice structure material can be greatly affected by the strut diameter sizes due to increase in stiffness as the strut diameter increases. The mathematical equation is also derived to calculate the total area moments of inertia of the lattice structure model and the validity of this developed model is shown through comparison of the results with experimental work of the three-point bending test which shown similar increase trend. Thus, this study provides information on the influence of strut diameter design parameter on its vibration characteristic.

Environmental and Economic Analysis of FDM, SLS and MJF Additive Manufacturing Technologies.

In this study, the authors present a comparative analysis of different additive manufacturing (AM) technologies for high-performance components. Four 3D printers, currently available on the Italian national manufacturing market and belonging to three different AM technologies, were considered. The analysis focused on technical aspects to highlight the characteristics and performance limits of each technology, economic aspects to allow for an assessment of the costs associated with the different processes, and environmental aspects to focus on the impact of the production cycles associated with these technologies on the ecosystem, resources and human health. This study highlighted the current limits of additive manufacturing technologies in terms of production capacity in the case of large-scale production of plastic components, especially large ones. At the same time, this study highlights how the geometry of the object to be developed greatly influences the optimal choice between the various AM technologies, in both technological and economic terms. Fused deposition modeling (FDM) is the technology that exhibits the greatest limitations hindering mass production due to production times and costs, but also due to the associated environmental impact.

Research on an automatic leveling method with a feedback mode for a parallel 3D printer

PurposeThe purpose of this study is to propose an automatic leveling method for a printing platform based on a three-point coordinate feedback. The proposed method is used in fused deposition modeling additive manufacturing systems. The coordinate error of the leveled plane is constrained to within  ± 0.2 mm, which is less than the printed layer thickness.Design/methodology/approachFirst, the model of the forward and inverse solutions of the parallel arm is obtained based on the principles of vector algebra. Second, the automatic leveling mechanism for collecting the z-coordinate is designed. The best position of the virtual origin plane is obtained by comparing the z-coordinates of the test points. Finally, after making multiple adjustments through a closed-loop z-coordinate feedback, the parallelism of the printing plane and the virtual origin plane is limited to an effective range.FindingsThe experimental results show that after three leveling attempts, the z-coordinate of the test points can be constrained to within  ± 0.2 mm, which shows that this method can effectively achieve automatic leveling in a delta three-dimensional (3D) printer.Originality/valueThis study presents a novel and distinctive delta 3D printer leveling system by designing a leveling mechanism and a leveling algorithm. The method uses a closed-loop feedback mode to make the leveling process simple, convenient and efficient without requiring major changes to the printer. The error after leveling is less than the printed layer thickness, which fully guarantees the accuracy of the leveling process.

Optimising the FDM additive manufacturing process to achieve maximum tensile strength: a state-of-the-art review

PurposeAdditive manufacturing or “3D printing” is a rapidly expanding sector and is moving from a prototyping service to a manufacturing service in its own right. With a significant increase in sales, fused deposition modelling (FDM) printers are now the most prevalent 3D printer on the market. The increase in commercial manufacturing necessitates an improved understanding of how to optimise the FDM printing process for various product mechanical properties. This paper aims to identify optimum print parameters for the FDM process to achieve maximum tensile strength through a review of recent studies in this field.Design/methodology/approachThe effect of the governing printing parameters on the tensile strength of printed samples will be considered, including material selection, print orientation, raster angle, air gap and layer height.FindingsThe key findings include material recommendations, such as the use of emerging print materials like polyether-ether-ketone (PEEK), to produce samples with tensile strength over 200 per cent that of conventional materials such as acrylonitrile butadiene styrene (ABS). Amongst other parameters, it is shown that printing in the “upright” orientation should be avoided (samples can be up to 50 per cent weaker in this orientation) and air gap and raster width should be concurrently optimised to ensure good “inter-raster” bonding. The optimal choice of raster angle depends on print material; in ABS for example, selecting a 0° raster angle over a 90° angle can increase tensile strength by up to 100 per cent.Originality/valueThe paper conclusions provide researchers and practitioners with an up-to-date, single point reference, highlighting a series of robust recommendations to optimise the tensile strength of FDM-printed samples. Improving the mechanical performance of FDM-printed samples will support the continued growth of this technology as a viable production technique.

Sustainable FDM additive manufacturing of ABS components with emphasis on energy minimized and time efficient lightweight construction

Fused Deposition Modeling (FDM) is a widely used additive manufacturing process with applications in rapid prototyping and rapid manufacturing. In view of increasing trend of sustainable manufacturing, the present study was focused on analyzing the process sustainability with an objective to ensure lightweight construction with minimized energy consumption and printing time. Having extensive applications in industry and being an amenable printing material, Acrylonitrile Butadiene Styrene (ABS) was used as the test material. A Design of Experiments (DoE) composed of 46 tests was conducted by varying four different printing parameters namely layer thickness, fill density, feed rate and shell thickness. Three important measures of sustainable manufacturing (specific energy, specific mass and specific time) were measured during experimentation. The statistical variance analysis was performed on the DoE results, which revealed that the considered printing parameters had significant influence on the mentioned sustainability measures with an exception that the feed rate did not affect the specific mass. The values of these measures were observed to decrease with a decrease in the fill density and shell thickness, and an increase in the layer thickness and feed rate: feed rate, however, did not affect the specific mass. The degree of these effects was observed to depend on the companion printing parameters thereby showing strong interactive and complex effects of parameters. This suggests that the printing parameters should be chosen judiciously in order to achieve sustainable printing, for which results presented in this study can be greatly helpful. Regression analysis was performed to devise prediction models with a purpose to estimate considered sustainability measures for FDM printing of ABS material. Finally, optimum printing conditions are proposed in order to ensure sustainable printing in the FDM process.

A manufacturing cost analysis framework to evaluate machining and fused filament fabrication additive manufacturing approaches

The goal of this research is to develop a costing framework and explore opportunities for fabricating components using additive manufacturing (AM) and machining approaches. The examples target plastic machining, and the fused deposition modeling AM process, but the general model structure is applicable for other AM processes as process knowledge is developed. The question “when is machining more cost-effective than AM” has not been comprehensively addressed. The purpose of this work is to develop a costing framework to provide insight on whether to use machining or AM. An estimation model which considers the process planning, setup, and fabrication time-cost elements is developed in a structured manner. This is challenging due to the machining process planning complexity, the decision-making, and the skill set required, especially for complex surface finish machining. This framework can be readily adapted to suit specific environments. The estimation time models are linked to a cost model, and comparisons are drawn, based on the form complexity and manufacturing quantity. An effective combination of AM and machining technologies could bring about a new hybrid manufacturing approach that meets the requirements of the next generation of production systems, especially for short-run production. A cost-benefit analysis is performed to illustrate solution approaches for designing additive, subtractive, or hybrid operation sets for a variety of components to highlight the merits of the presented approach. Exploring a larger solution space of processing options and their processing time and costs will allow designers to generate more cost-competitive solutions.

Fabrication of Patient Specific Knee Implant by Fused Deposition Modeling

Abstract The aim of this research work is to Fabricate Patient Specific knee implant which is a surgical method of replacing the load bearing surfaces present in the knee joint so as to fix the pain bearing locals and inability zones of the joint. In this research, a proposed three-dimensional model of knee implant is developed from stl file which was obtained from sunshine hospital, secunderabad by using Fused Deposition modeling additive manufacturing process. Fabricated specimen is developed in software’s like meshlab, NetFabb and CATIA. After getting 3D model, it is then given to FDM machine for building. The knee implant printing time and material consumed is determined.

Application of low-cost fused deposition modeling additive manufacturing rapid anatomic models in patients with rhino-cerebral mucormycosis treated with maxillectomy

Mucormycosis is a fungal infection mainly of immunocompromised patients. It has many clinical manifestations depending on the system that is affected. Rhinocerebral mucormycosis and pulmonary infection are the most common. In this pathology, the fungi invade the endothelium of the blood vessels with partial or total obliteration, with tissue ischemia and necrosis. The initial symptoms are unspecific making difficult to identify from other infections and need an expert suspicion level. The gold standard is the culture of the fungi; histopathology analysis shows empty hyphae with thin walls. Combined treatment is strongly recommended surgical extended debridement and Amphotericin B is the gold standard of treatment. The craniofacial skeleton (CS) has a very peculiar bone and soft tissue distribution that maintains height, width, and projection. In RCM, aggressive debridement is prognostic for patient survival. Extensive maxillectomies, often with orbital exenteration represent a reconstructive challenge for plastic surgeons. Recently different types of additive manufacture (AM) technology had been proposed in surgical planning. Fused deposition manufacture (FDM) technology could be the most cost-effective for patients. To the best of our knowledge, this is the first report of the use of FDM and reconstruction of patients with RCM. RCM is a very serious life-threatening condition. When treated in time with the adequate surgical approach and a correct antifungal medicine RCM can be a cured. The goals in treating this condition are very clear. A free flap reconstruction is an adequate approach to patients with RCM and FDM RAM can help the surgeon to plan the free flap in site. We present two cases reconstructed with MSAP and ALT-FL respectively with success assisted with FDM RAM. Level of Evidence: Level V, therapeutic study.

Consistency analysis of mechanical properties of elements produced by FDM additive manufacturing technology

Additive manufacturing (AM) technology refers to the process of producing 3D objects by adding material in successive layers. Fused deposition modeling (FDM) is one of the AM technologies where objects are built by adding layers of melted thermoplastic filament onto the printing surface. Mechanical properties of FDM printed part depend on many influencing factors such as material composition, extruding temperature, printing parameters and environment temperature. The aim of this study was to investigate consistency of mechanical properties of elements produced by FDM additive manufacturing technology. To do so, mechanical tensile and compression tests were conducted on ten samples using polylactic acid (PLA) and ten samples using acrylonitrile butadiene styrene (ABS) thermoplastic material. Tensile tests were conducted using Shimadzu Compact Tabletop Testing Machine EZ-LX and the compression tests were done using VEB ZDM 5/91 testing machine. The ultimate tensile strength, strain, Young modulus and compression yield strength values were analyzed. The ABS thermoplastic material showed greater consistency in mechanical properties during tensile tests. Tensile strength values for PLA material varied between samples thus showing greater inconsistency in repeatability of mechanical properties. Compression tests, on the other hand, showed that PLA samples had greater consistency in mechanical properties compared to ABS samples. Keywords: additive manufacturing, FDM, mechanical properties.