Low-cost Fused Filament Fabrication Research Articles

Empowering Rehabilitation: Design and Structural Analysis of a Low-Cost 3D-Printed Smart Orthosis.

Three-dimensional (3D) printing of polymer materials encompasses a wide range of applications and innovations. Polymer-based 3D printing, also known as additive manufacturing, has gained significant attention due to its versatility, cost-effectiveness, and potential to revolutionize various industries. The current paper focuses on obtaining a durable low-cost rehabilitation knee orthosis. Researchers propose that the entire structure should be obtained using modern equipment within the additive manufacturing domain-3D printing. The researchers focus on determining, through a 3D analysis of the entire 3D model assembly, which parts present a high degree of stress when a kinematic simulation is developed. The entire 3D model of the orthosis starts based on the result obtained from a 3D scanning of the knee joint of a patient, providing a precise fixation, and allowing for direct personalization. Based on the results and identification of the critical parts, there will be used different materials and a combination of 3D printing strategies to validate the physical model of the entire orthosis. For the manufacturing process, the researchers use two types of low-cost fused filament fabrication (FFF), which are easy to find on the worldwide market. The motivation for manufacturing the entire assembly using 3D printing techniques is the short time in which complex shapes can be obtained, which is relevant for the present study. The main purpose of the present research is to advance orthotic technology by developing an innovative knee brace made of 3D-printed polymers that are designed to be lightweight, easy-to-use, and provide comfort and functionality to patients during the rehabilitation process.

Modification of a desktop FFF printer via NIR laser addition for upconversion 3D printing

Traditional photopolymer-based 3D printing methods require sequential printing of thin layers, due to short penetration depths of UV or blue light sources used by these techniques. In contrast, upconversion 3D printing circumvents the layer-by-layer limitation by taking advantage of upconversion luminescence processes and the high penetration depths offered by near-infrared (NIR) lasers, allowing for selective crosslinking of voxels at any depth or position within the resin container. The implementation of this technique required the construction of a 3D printer with the ability of focusing the laser on any point of the space. For this, a low-cost fused filament fabrication (FFF) printer was modified by incorporating a 980 nm laser and laser control circuit. The total cost of the parts required for modification was £180. With enhanced penetration depths up to 5.8 cm, this method also allows for printing inside or through existing 3D printed parts. This opens doors for restoration of broken items, in situ bioprinting, 3D-circuitry, and notably, 3D printing inside cavities of a different material, illustrating numerous opportunities for practical applications.

3D Printing of a Tidal Turbine Blade Using Two Methods of SLS and FFF of a Reinforced PA12 Composite: A Comparative Study

This study scrutinizes the thermomechanical dynamics of 3D-printed hydrofoil blades utilizing a carbon and glass bead-reinforced thermoplastic polymer. Comparative analyses underscore the pivotal role of polymer reinforcement in augmenting mechanical strength and mitigating deformation and residual stress. The investigation elucidates the expeditious and cost-efficient manufacturing potential of low-cost Fused Filament Fabrication (FFF) printers for small-scale blades, revealing exemplary mechanical performance with nominal deflection and warping in the PA12-CB/GB printed blade. A comprehensive juxtaposition between Selective Laser Sintering (SLS) and FFF printing methods favors SLS due to its isotropic properties, notwithstanding remediable warping. Emphasizing the rigorous marine environment, the study cautions against the anisotropic properties of FFF-printed blades, despite their low mechanical warping. These discernments contribute to hydrofoil design optimization through numerical analysis, shedding light on additive manufacturing’s potential for small blades in renewable energy, while underscoring the imperative for further research to advance these techniques.

Evaluating 3D printed mesh geometries in ceramic LiB electrodes

Additive manufacturing techniques have the potential to promote a paradigmatic change in the electrode fabrication processes for lithium-ion batteries (LiBs) as they may offer alternative component designs to boost their performance or to customise the application. The present research work explores the use of low-cost fused filament fabrication (FFF) 3D printing to fabricate Li4Ti5O12 (LTO) mesh electrodes in the search for enlarged electrochemically active areas. Using different nozzle diameters (ND), we have 3D printed several mesh electrodes that after sintering allow an increase in the surface to volume ratio by up to ≈290% compared to conventional flat cylindrical geometries. As the conventional route to produce 3D printed meshes, i.e. stacking of consecutive layers with a 90° rotation, leads to problems of vertical misalignment that may affect the electrical contact, we have developed a new compact design that maximises the contact between layers. All the 3D printed mesh electrodes with thicknesses of 400 and 800 μm, exhibit electrochemical performance very close to those of thin (70 μm) electrodes, e.g. 175 mAh g−1 at C/2 in the case of ND = 100 μm, which is the theoretical capacity value for LTO. At higher C-rates, 800 μm-thick mesh electrodes with larger ND exhibit a marked drop in the reversible capacity (28 mAh g−1 at 8 C), although the values obtained improve notably those of the equivalent thick solid electrode (almost null at 8 C). The compact design demonstrated superior performance at high C-rates, improving by ≈70% the results of the best conventional mesh electrode at 8 C for 800 μm electrodes. These results highlight the potential of FFF-3D printing to generate novel high aspect ratio geometries and the impact of design and printing parameters on the performance of LiB electrode materials. Exploring alternative efficient geometries may facilitate the integration of thick electrodes in high energy density LiBs.

Design and Development of highly filled calcium sulfate-poly lactic acid biocomposites as feedstock for low-cost fused filament fabrication

Three-dimensional (3D) printing has been used as a promising technology in biomedical sciences and engineering. However, there is a lack of ready-to-use feedstock for biomedical applications. In this work, a series of PLA biocomposite filled with calcium sulfate (CaS) particles up to a maximum content of 40 wt% has been prepared by solvent casting method and subsequently processed into filament form through the melt compounding method. The objective of this study was to investigate the processibility of composite filament with maximum ceramic content through fused filament fabrication (FFF) process to improve the mechanical, thermal and biological performance of virgin PLA for biomedical application. The composite filament was extruded at a temperature of 160 °C at a constant speed with an average diameter of 1.70 ± 08 mm, compatible with the 3D printer's feeding system. Morphological, thermal, mechanical, and crystallization analysis using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and thermogravimetric (TGA) analysis was performed on the extruded filament to evaluate the effect of ceramic content in the polymeric matrix. The thermal stability was improved upon addition of CaS particles into the PLA matrix. Subsequently, PLA-CaS solid specimen was 3D-printed and characterized for its mechanical, and geometrical accuracy. The maximum compressive strength obtained is 115 MPa for 20% ceramic loading, which then decreases with increased ceramic content. The biocompatibility test using MC3T3E1 cells confirmed zero cytotoxicity and cell grows well on all PLA and composite specimen. The results revealed that the composite biomaterials could be easily printed even at high ceramic loading and maintain their structural integrity and stability during the additive manufacturing process. These composites could be potential candidates for various biomedical applications, such as bone scaffolds and bioresorbable screws for Anterior Cruciate Ligament (ACL) reconstruction.

Trueness of cone-beam computed tomography-derived skull models fabricated by different technology-based three-dimensional printers

BackgroundThree-dimensional (3D) printing is a novel innovation in the field of craniomaxillofacial surgery, however, a lack of evidence exists related to the comparison of the trueness of skull models fabricated using different technology-based printers belonging to different cost segments.MethodsA study was performed to investigate the trueness of cone-beam computed tomography-derived skull models fabricated using different technology based on low-, medium-, and high-cost 3D printers. Following the segmentation of a patient’s skull, the model was printed by: (i) a low-cost fused filament fabrication printer; (ii) a medium-cost stereolithography printer; and (iii) a high-cost material jetting printer. The fabricated models were later scanned by industrial computed tomography and superimposed onto the original reference virtual model by applying surface-based registration. A part comparison color-coded analysis was conducted for assessing the difference between the reference and scanned models. A one-way analysis of variance (ANOVA) with Bonferroni correction was applied for statistical analysis.ResultsThe model printed with the low-cost fused filament fabrication printer showed the highest mean absolute error (1.33pm 0.24 text{mm}), whereas both medium-cost stereolithography-based and the high-cost material jetting models had an overall similar dimensional error of 0.07pm 0.03 text{mm} and 0.07pm 0.01 text{mm}, respectively. Overall, the models printed with medium- and high-cost printers showed a significantly (p<0.01) lower error compared to the low-cost printer.ConclusionsBoth stereolithography and material jetting based printers, belonging to the medium- and high-cost market segment, were able to replicate the skeletal anatomy with optimal trueness, which might be suitable for patient-specific treatment planning tasks in craniomaxillofacial surgery. In contrast, the low-cost fused filament fabrication printer could serve as a cost-effective alternative for anatomical education, and/or patient communication.

Biomass waste materials through extrusion-based additive manufacturing: A systematic literature review

Circular economy and bioeconomy models have increasingly spread the principles of sustainable development through different strategies such as reuse and recycling. Biomass waste and by-products are often considered valuable resources. Digital technologies, i.e., extrusion-based additive manufacturing, may potentially foster their exploitation as new materials, although the current framework has not been clearly defined yet. This work wants to systematically review the publications focused on new materials from biomass waste or by-products for extrusion-based additive manufacturing processes. The current situation was analyzed on 69 selected works from 2016 searched on Scopus and WoS, focusing on the different raw materials, new 3D printable materials, 3D printing processes, and potential applications. Afterward, the emerging trends were highlighted through selected best practices from the design practice and industrial sectors. Despite the significant development of thermoplastic reinforced materials, i.e., PLA-filled composites, a wide range of biomass waste and by-products have been studied, especially for small format low-cost Fused Filament Fabrication. Although the academic field may be less focused on exploiting these new circular materials, the interest in new applications is increasing within the design practice and industrial sectors, fostering new synergies within bioeconomy and circular economy contexts.

Sustainable Polymer Composites Manufacturing through 3D Printing Technologies by Using Recycled Polymer and Filler.

In the last years, the excessive use of plastic and other synthetic materials, that are generally difficult to dispose of, has caused growing ecological worries. These are contributing to redirecting the world’s attention to sustainable materials and a circular economy (CE) approach using recycling routes. In this work, bio-filaments for the Fused Filament Fabrication (FFF) 3D printing technique were produced from recycled polylactic acid (PLA) and artisanal ceramic waste by an extrusion process and fully characterized from a physical, thermal, and mechanical point of view. The data showed different morphological, thermal, rheological, and mechanical properties of the two produced filaments. Furthermore, the 3D objects produced from the 100% recycled PLA filament showed lower mechanical performance. However, the results have demonstrated that all the produced filaments can be used in a low-cost FFF commercial printer that has been modified with simple hand-made operations in order to produce 3D-printed models. The main objective of this work is to propose an example of easy and low-cost application of 3D printing that involves operations such as the reprocessing and the recyclability of materials, that are also not perfectly mechanically performing but can still provide environmental and economic benefits.

Biomechanical validation of additively manufactured artificial femoral bones

Replicating the mechanical behavior of human bones, especially cancellous bone tissue, is challenging. Typically, conventional bone models primarily consist of polyurethane foam surrounded by a solid shell. Although nearly isotropic foam components have mechanical properties similar to cancellous bone, they do not represent the anisotropy and inhomogeneity of bone architecture. To consider the architecture of bone, models were developed whose core was additively manufactured based on CT data. This core was subsequently coated with glass fiber composite. Specimens consisting of a gyroid-structure were fabricated using fused filament fabrication (FFF) techniques from different materials and various filler levels. Subsequent compression tests showed good accordance between the mechanical behavior of the printed specimens and human bone. The unidirectional fiberglass composite showed higher strength and stiffness than human cortical bone in 3-point bending tests, with comparable material behaviors being observed. During biomechanical investigation of the entire assembly, femoral prosthetic stems were inserted into both artificial and human bones under controlled conditions, while recording occurring forces and strains. All of the artificial prototypes, made of different materials, showed analogous behavior to human bone. In conclusion, it was shown that low-cost FFF technique can be used to generate valid bone models and selectively modify their properties by changing the infill.

Influence of Printing Parameters on Self-Cleaning Properties of 3D Printed Polymeric Fabrics.

The processes for making self-cleaning textile fabrics have been extensively discussed in the literature. However, the exploration of the potential for self-cleaning by controlling the fabrication parameters of the fabric at the microscopic level has not been addressed. The current evolution in 3D printing technology provides an opportunity to control parameters during fabric manufacturing and generate self-cleaning features at the woven structural level. Fabrication of 3D printed textile fabrics using the low-cost fused filament fabrication (FFF) technique has been achieved. Printing parameters such as orientation angle, layer height, and extruder width were used to control self-cleaning microscopic features in the printed fabrics. Self-cleaning features such as surface roughness, wettability contact angle, and porosity were analyzed for different values of printing parameters. The combination of three printing parameters was adjusted to provide the best self-cleaning textile fabric surface: layer height (LH) (0.15, 0.13, 0.10 mm) and extruder width (EW) (0.5, 0.4, 0.3 mm) along with two different angular printing orientations (O) (45° and 90°). Three different thermoplastic flexible filaments printing materials were used: thermoplastic polyurethane (TPU 98A), thermoplastic elastomers (TPE felaflex), and thermoplastic co-polyester (TPC flex45). Self-cleaning properties were quantified using a pre-set defined criterion. The optimization of printing parameters was modeled to achieve the best self-cleaning features for the printed specimens.

Development of Fused Filament Fabrication desktop 3D printer enclosure using axiomatic design principles

Additive manufacturing through Fused Filament Fabrication is one of the most spread methods for obtaining functional prototypes and components, mainly for single parts demands or small manufacturing lots. This direction of use presumes the use of engineering polymers in the manufacturing process, materials that require precise control of the environment regarding printing temperature and moisture. A Do-It-Yourself enclosure mock-up for engineering polymers processing was obtained using the Axiomatic Design principles. The enclosure is compatible with low-cost Fused Filament Fabrication desktop 3D printers and satisfies the functional requirements regarding manufacturing and secure usage of engineering-grade polymers. In addition, the presented design solved the requirements regarding surveillance and remote control during the manufacturing process.

Energy consumption of common desktop additive manufacturing technologies

Additive manufacturing (AM), also referred as 3D printing, is a small but fast-growing sub-sector of the manufacturing industry. Concerns over increasing worldwide energy consumption provides an impetus to quantify the energy use of the most common forms of AM technologies. To date, research efforts have focussed on the energy use of industrial AM machines, and little research has been conducted on the numerous low-cost desktop 3D printers. Additionally, there is a gap in our knowledge of how to minimise the energy consumption of desktop 3D printers and how to predict their energy use. To fill this gap, high resolution (1 ​Hz) power measurements were made for a range of low-cost fused filament fabrication and vat polymerisation desktop 3D printers. The volumetric specific energy use was found to be 24.8–85.7 ​kJ/cm3 and 10.8–21.5 ​kJ/cm3 for fused filament fabrication and vat polymerisation respectively. Semi-empirical equations were developed that can accurately predict the energy use for each printing technology based on simple 3D printing metrics.

Fused Filament Fabrication 4D Printing of a Highly Extensible, Self-Healing, Shape Memory Elastomer Based on Thermoplastic Polymer Blends.

A polymer blend with high extensibility, exhibiting both shape memory and self-healing, was 4D printed using a low-cost fused filament fabrication (FFF, or fused deposition modeling, FDM) 3D printer. The material is composed of two commercially available commodity polymers, polycaprolactone (PCL), a semi-crystalline thermoplastic, and polystyrene-block-poly(ethylene-co-butylene)-block-polystyrene (SEBS), a thermoplastic elastomer. The shape memory and self-healing properties of the blends were studied systematically through thermo-mechanical and morphological characterization, providing insight into the shape memory mechanism useful for tuning the material properties. In 3D-printed articles, the orientation of the semi-crystalline and micro-phase-separated domains leads to improvement of the shape memory property and extensibility of this material compared to compression-molded samples. By controlling the orientation of the printed fibers, we achieved a high strain at break over 1200%, outperforming previously reported flexible 4D-printed materials. The self-healing agent, PCL, enables the material to heal scratches and cracks and adhere two surfaces after annealing at 80 °C for 30 min. The high performance, multi-functionality, and potential scalability make it a promising candidate for a broad spectrum of applications, including flexible electronics, soft actuators, and deployable devices.

Analysis of PLA Geometric Properties Processed by FFF Additive Manufacturing: Effects of Process Parameters and Plate-Extruder Precision Motion.

The evolution of fused filament fabrication (FFF) technology, initially restricted to the manufacturing of prototypes, has led to its application in the manufacture of finished functional products with excellent mechanical properties. However, FFF technology entails drawbacks in aspects, such as dimensional and geometric precision, and surface finish. These aspects are crucial for the assembly and service life of functional parts, with geometric qualities lagging far behind the optimum levels obtained by conventional manufacturing processes. A further shortcoming is the proliferation of low cost FFF 3D printers with low quality mechanical components, and malfunctions that have a critical impact on the quality of finished products. FFF product quality is directly influenced by printer settings, material properties in terms of cured layers, and the functional mechanical efficiency of the 3D printer. This paper analyzes the effect of the build orientation (Bo), layer thickness (Lt), feed rate (Fr) parameters, and plate-extruder movements on the dimensional accuracy, flatness error, and surface texture of polylactic acid (PLA) using a low cost open-source FFF 3D printer. The mathematical modelling of geometric properties was performed using artificial neural networks (ANN). The results showed that thinner layer thickness generated lower dimensional deviations, and feed rate had a minor influence on dimensional accuracy. The flatness error and surface texture showed a quasi-linear behavior correlated to layer thickness and feed rate, with alterations produced by 3D printer malfunctions. The mathematical models provide a comprehensive analysis of the geometric behavior of PLA processing by FFF, in order to identify optimum print settings for the processing of functional components.

Fused filament fabrication, debinding and sintering as a low cost additive manufacturing method of 316L stainless steel

By using filaments comprising metal or ceramic powders and polymer binders, solid metal and ceramic parts can be created by combining low-cost fused filament fabrication (FFF) with debinding and sintering. In this work, we explored a fabrication route using a FFF filament filled with 316 L steel powder at 55 vol.-%. We investigated the printing, debinding and sintering parameters and optimized them with respect to the mechanical properties of the final part. Special focus was placed on debinding and sintering in order to obtain components of low residual porosity. Solvent debinding of the printed green bodies created an internal network of interconnected pores and was followed by thermal debinding. Thermal debinding allowed for complete removal of the remaining binder and produced mechanically stable brown parts. Sintering at 1360 °C provided densification of the parts and generated nearly isotropic linear shrinkage of about 20%. Using optimized parameters, it was possible to fabricate 316 L steel components with a density greater than 95% via the material extrusion additive manufacturing, debinding and sintering route, with achievable deflections in a 3-point bending test similar to rolled sheet material, albeit at lower strength.

Single-operation, multi-phase additive manufacture of electro-chemical double layer capacitor devices

Additive manufacturing (AM) may offer a flexible, cost-effective approach to address conventional manufacturing limitations, such as time-consuming, high work-in-progress, multi-step assembly. In principle AM can also allow more novel geometric or even bespoke designs of structural and functional products. However, in terms of energy storage devices such as batteries and supercapacitors, the benefits of AM have not yet been explored to any significant extent. In this paper, a hybrid-AM system, combining low-cost fused filament fabrication (FFF) and direct ink writing (DIW) techniques, has been designed to fabricate supercapacitors (electro-chemical double layer capacitors, EDLCs) in a single, automated operation. The inherent flexibility of the AM process provided an opportunity to address restrictions in geometric form factor associated with conventional planar supercapacitor manufacturing approaches. Functioning, ring-shaped EDLC devices were manufactured in a single, multi-material operation comprising symmetric activated carbon electrodes in a 1Μ potassium hydroxide (KOH) electrolyte hydrogel. Gravimetric and areal electrode capacitances were 116.4 ± 0.6 F g−1 and 599.2 ± 3.0 mF cm−2 at 10 mV s−1, with a columbic efficiency of 99.6 ± 0.4% in the as-printed condition. The work aims to accelerate progress towards monolithic integration of energy storage devices in product manufacture, offering an alternative fabrication process for applications with irregular volume/shape and mass-customization requirements.

3D Printed End of Arm Tooling (EOAT) for Robotic Automation

This research furthers the practice of designing and manufacturing End of Arm Tooling (EOAT) by utilizing a low cost additive manufacturing Fused Filament Fabrication (FFF) technique to enable tool weight saving and provision of low cost EOATs on demand, thereby facilitating zero inventory lean manufacturing. The materials used in this research for the fabrication of the EOAT parts were Acrylonitrile butadiene styrene (ABS) and nylon with infill densities of 20% and 100%. Three-point flexural tests were performed to determine the differences in strength and stiffness between varying polymers, infill ratios, and a standard metal part. Additionally, potential weight savings were identified and challenges with utilizing low cost FFF technologies are outlined. A motion of programmed trajectories was executed utilizing a standard 6-axis robot and the power consumption was evaluated. This study demonstrates the utility of using thermoplastic material with the fabrication of 3D printed parts used in EOATs.

Fused Filament Fabrication of Small Ceramic Components.

With respect to rapid prototyping of ceramic components, there are known only a few processes (stereo lithography, binder jetting). In this work, a new process chain is described in detail, showing that ceramics can be printed in a very cost-efficient way. We developed a ceramic–polymer composite as filament material that can be printed on a low-cost fused filament fabrication (FFF) desktop printer, even with very small nozzle sizes enabling very small geometric feature sizes. The thermal post-processing, with debinding and sintering, is very close to the ceramic injection molding (CIM) process chain.

Anisotropic mechanical property variance between ASTM D638-14 type i and type iv fused filament fabricated specimens

The open source introduction of fused filament fabrication (FFF) enables distributed manufacturing of consumer products. However, with a wide range of low-cost FFF 3-D printers and settings possible, there is a lack of information on the variability in printed mechanical properties. This paper utilizes a large pool of 47 user-assembled 3-D printers to quantify the mechanical property variations of ultimate tensile strength (UTS) and yield strength of FFF printed components using ASTM D638-14 horizontally-oriented Type I and IV geometries for poly lactic acid (PLA). The results indicate that utilizing Type IV tensile test piece geometry may overestimate the UTS relative to the Type I. Furthermore, anisotropic mechanical property variances were quantified for Type IV specimens (vertical and horizontal orientations). Vertical tensile specimens had an ultimate tensile strength 47.9% less than horizontal. Finally, the abundant supply of PLA 3-D prints suggest open-source printers assembled by individual operators can produce quality plastic components although the mechanical performance of the given part can vary dramatically based on the operator selection of printing parameters that provide a visually acceptable part.

Open Source Laser Polymer Welding System: Design and Characterization of Linear Low-Density Polyethylene Multilayer Welds

The use of lasers to weld polymer sheets provides a means of highly-adaptive and custom additive manufacturing for a wide array of industrial, medical, and end user/consumer applications. This paper provides an open source design for a laser polymer welding system, which can be fabricated with low-cost fused filament fabrication and off-the-shelf mechanical and electrical parts. The system is controlled with free and open source software and firmware. The operation of the machine is validated and the performance of the system is quantified for the mechanical properties (peak load) and weld width of linear low density polyethylene (LLDPE) lap welds manufactured with the system as a function of linear energy density. The results provide incident laser power and machine parameters that enable both dual (two layers) and multilayer (three layers while welding only two sheets) polymer welded systems. The application of these parameter sets provides users of the open source laser polymer welder with the fundamental requirements to produce mechanically stable LLDPE multi-layer welded products, such as heat exchangers.