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1
Karayannis, Panagiotis, Fotini Petrakli, Anastasia Gkika und Elias P. Koumoulos. „3D-Printed Lab-on-a-Chip Diagnostic Systems-Developing a Safe-by-Design Manufacturing Approach“. Micromachines 10, Nr. 12 (28.11.2019): 825. http://dx.doi.org/10.3390/mi10120825.
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The aim of this study is to provide a detailed strategy for Safe-by-Design (SbD) 3D-printed lab-on-a-chip (LOC) device manufacturing, using Fused Filament Fabrication (FFF) technology. First, the applicability of FFF in lab-on-a-chip device development is briefly discussed. Subsequently, a methodology to categorize, identify and implement SbD measures for FFF is suggested. Furthermore, the most crucial health risks involved in FFF processes are examined, placing the focus on the examination of ultrafine particle (UFP) and Volatile Organic Compound (VOC) emission hazards. Thus, a SbD scheme for lab-on-a-chip manufacturing is provided, while also taking into account process optimization for obtaining satisfactory printed LOC quality. This work can serve as a guideline for the effective application of FFF technology for lab-on-a-chip manufacturing through the safest applicable way, towards a continuous effort to support sustainable development of lab-on-a-chip devices through cost-effective means.
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Szmidt, Artur, und Anna Rębosz-Kurdek. „New approaches of improving FDM/FFF printing technology“. Mechanik 90, Nr. 3 (06.03.2017): 258–61. http://dx.doi.org/10.17814/mechanik.2017.3.46.
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This article presents new approaches of increasing the efficiency of FDM/FFF printing technology through the introduction of modifications to the form of filament and to the feeding mechanism. Currently used solutions and innovativeness of proposed concepts are discussed in the paper. A new approach concerning the modification of the filament form was presented in descriptive and graphic way. Moreover, constructional solutions of individual components of the patented (patent PL 224144 B1) filament feeding mechanism including a description of its operation were proposed.
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Caminero, Miguel Ángel, Ana Romero, Jesús Miguel Chacón, Pedro José Núñez, Eustaquio García-Plaza und Gloria Patricia Rodríguez. „Additive manufacturing of 316L stainless-steel structures using fused filament fabrication technology: mechanical and geometric properties“. Rapid Prototyping Journal 27, Nr. 3 (27.01.2021): 583–91. http://dx.doi.org/10.1108/rpj-06-2020-0120.
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Purpose Fused filament fabrication (FFF) technique using metal filled filaments in combination with debinding and sintering steps can be a cost-effective alternative for laser-based powder bed fusion processes. The mechanical behaviour of FFF-metal materials is highly dependent on the processing parameters, filament quality and adjusted post-processing steps. In addition, the microstructural material properties and geometric characteristics are inherent to the manufacturing process. The purpose of this study is to characterize the mechanical and geometric performance of three-dimensional (3-D) printed FFF 316 L metal components manufactured by a low-cost desktop 3-D printer. The debinding and sintering processes are carried out using the BASF catalytic debinding process in combination with the BASF 316LX Ultrafuse filament. Special attention is paid on the effects of build orientation and printing strategy of the FFF-based technology on the tensile and geometric performance of the 3-D printed 316 L metal specimens. Design/methodology/approach This study uses a toolset of experimental analysis techniques [metallography and scanning electron microcope (SEM)] to characterize the effect of microstructure and defects on the material properties under tensile testing. Shrinkage and the resulting porosity of the 3-D printed 316 L stainless steel sintered samples are also analysed. The deformation behaviour is investigated for three different build orientations. The tensile test curves are further correlated with the damage surface using SEM images and metallographic sections to present grain deformation during the loading progress. Mechanical properties are directly compared to other works in the field and similar additive manufacturing (AM) and Metal Injection Moulding (MIM) manufacturing alternatives from the literature. Findings It has been shown that the effect of build orientation was of particular significance on the mechanical and geometric performance of FFF-metal 3-D printed samples. In particular, Flat and On-edge samples showed an average increase in tensile performance of 21.7% for the tensile strength, 65.1% for the tensile stiffness and 118.3% for maximum elongation at fracture compared to the Upright samples. Furthermore, it has been able to manufacture near-dense 316 L austenitic stainless steel components using FFF. These properties are comparable to those obtained by other metal conventional processes such as MIM process. Originality/value 316L austenitic stainless steel components using FFF technology with a porosity lower than 2% were successfully manufactured. The presented study provides more information regarding the dependence of the mechanical, microstructural and geometric properties of FFF 316 L components on the build orientation and printing strategy.
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Czyżewski, Piotr, Marek Bieliński, Dariusz Sykutera, Marcin Jurek, Marcin Gronowski, Łukasz Ryl und Hubert Hoppe. „Secondary use of ABS co-polymer recyclates for the manufacture of structural elements using the FFF technology“. Rapid Prototyping Journal 24, Nr. 9 (12.11.2018): 1447–54. http://dx.doi.org/10.1108/rpj-03-2017-0042.
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Purpose The aim of this paper is presenting a new application of material obtained from the acrylonitrile butadiene styrene (ABS) recycling process from electronic equipment housings. Elements of computer monitors were used to prepare re-granulate, which in turn was used to manufacture a filament for fused filament fabrication (FFF) additive manufacturing technology. Design/methodology/approach The geometry of test samples (i.e. dumbbell and bar) was obtained in accordance with the PN-EN standards. Samples made with the FFF technology were used to determine selected mechanical properties and to compare the results obtained with the properties of ABS re-granulate mould pieces made with the injection moulding technology. The GATE device manufactured by 3Novatica was used to make the prototypes with the FFF technology. Processing parameters were tested with the use of an Aflow extrusion plastometer manufactured by Zwick/Roell and other original testing facilities. Tests of mechanical properties were performed with a Z030 universal testing machine, a HIT 50P pendulum impact tester and a Z3106 hardness tester manufactured by Zwick/Roell. Findings The paper presents results of tests performed on a filament obtained from the ABS re-granulate and indicates characteristic processing properties of that material. The properties of the new secondary material were compared with the available original ABS materials that are commonly used in the additive technology of manufacturing geometrical objects. The study also presents selected results of tests of functional properties of ABS products made in the FFF technology. Originality/value The test results allowed authors to assess the possibility of a secondary application of used elements of electronic equipment housings in the FFF technology and to compare the strength properties of products obtained with similar products made with the standard injection moulding technology.
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Khan, Shaheryar Atta, Bilal Ahmed Siddiqui, Muhammad Fahad und Maqsood Ahmed Khan. „Evaluation of the Effect of Infill Pattern on Mechanical Stregnth of Additively Manufactured Specimen“. Materials Science Forum 887 (März 2017): 128–32. http://dx.doi.org/10.4028/www.scientific.net/msf.887.128.
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Additive manufacturing has stepped down from the world of Sci-Fi into reality. Since its conception in the 1980s the technology has come a long way. May variants of the technology are now available to the consumer. With the advent of custom built (open source) Fused Deposition Modeling based printing technology Fused Filament Fabrication (FFF), FDM/FFF has become the most used Additive Manufacturing technology. The effects of the different infill patterns of FDM/FFF on the mechanical properties of a specimen made from ABS are studied in this paper. It is shown that due to changes in internal structures, the tensile strength of the specimen changes. The study also investigate the effect of infill pattern on the build time of the specimen. Extensive testing yielded the optimal infill pattern for FDM/FFF. An open source Arduino based RepRap printer was used for the preparation of specimen and showed promising results for rapid prototyping of custom built parts to bear high loads. The study can help with the increase in the use of additive manufacturing for the manufacturing of mechanically functioning parts such as prosthetics
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Ahroni, Y., N. Dresler, A. Ulanov, D. Ashkenazi, M. Aviv, M. Librus und A. Stern. „Selected Applications of Stimuli-Responsive Polymers: 4D Printing by the Fused Filament Fabrication Technology“. Annals of Dunarea de Jos University of Galati Fascicle XII Welding Equipment and Technology 31 (28.12.2020): 13–22. http://dx.doi.org/10.35219/awet.2020.02.
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In the past few years four-dimensional (4D) printing technologies have attained worldwide interest and they are now considered the "next big thing". The aim of this research is to provide three selected examples of stimuli-responsive polymer (SRP) applications additively manufactured (AM) by the fused filament fabrication (FFF) technique. To that end, a CCT BLUE filament of thermo-responsive polymer was chosen to produce a water temperature indicator, which changes colour from blue to white when temperature increases; a CCU RED filament of photo-responsive polymer was used to produce a sunlight / UV indicator bracelet; a transparent PLA CLEAR polymer, a CCU RED photo-responsive polymer, and an electrical conductive PLA polymer were selected to produce a smart business card stand. The temperature indicator capability was analysed based on examining colour changes as a function of temperature changes. The sunlight/UV indicator capability was analysed based on the inspection of colour change as a function of absorbed sun/ultraviolet light. The electrical conductivity of the conductive PLA polymer was examined by performing resistance measurements. All three objects were successfully produced and their functionality was demonstrated. We hope that these examples will catalyse the expansion of FFF 4D printed SRP applications, as much work remains to be done in designing the parts and developing FFF printing parameters that take advantage of the stimuli-responsive materials currently being developed for FFF technology.
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Honigmann, Philipp, Neha Sharma, Brando Okolo, Uwe Popp, Bilal Msallem und Florian M. Thieringer. „Patient-Specific Surgical Implants Made of 3D Printed PEEK: Material, Technology, and Scope of Surgical Application“. BioMed Research International 2018 (2018): 1–8. http://dx.doi.org/10.1155/2018/4520636.
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Additive manufacturing (AM) is rapidly gaining acceptance in the healthcare sector. Three-dimensional (3D) virtual surgical planning, fabrication of anatomical models, and patient-specific implants (PSI) are well-established processes in the surgical fields. Polyetheretherketone (PEEK) has been used, mainly in the reconstructive surgeries as a reliable alternative to other alloplastic materials for the fabrication of PSI. Recently, it has become possible to fabricate PEEK PSI with Fused Filament Fabrication (FFF) technology. 3D printing of PEEK using FFF allows construction of almost any complex design geometry, which cannot be manufactured using other technologies. In this study, we fabricated various PEEK PSI by FFF 3D printer in an effort to check the feasibility of manufacturing PEEK with 3D printing. Based on these preliminary results, PEEK can be successfully used as an appropriate biomaterial to reconstruct the surgical defects in a “biomimetic” design.
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García Plaza, Eustaquio, Pedro Núñez López, Miguel Caminero Torija und Jesús Chacón Muñoz. „Analysis of PLA Geometric Properties Processed by FFF Additive Manufacturing: Effects of Process Parameters and Plate-Extruder Precision Motion“. Polymers 11, Nr. 10 (27.09.2019): 1581. http://dx.doi.org/10.3390/polym11101581.
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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.
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Jiang, Shijie, Yannick Siyajeu, Yinfang Shi, Shengbo Zhu und He Li. „Improving the forming quality of fused filament fabrication parts by applied vibration“. Rapid Prototyping Journal 26, Nr. 1 (06.01.2020): 202–12. http://dx.doi.org/10.1108/rpj-12-2018-0314.
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Purpose The purpose of this study is to investigate the efficiency of applied vibration in improving the forming quality (mechanical property and dynamics characteristics) of fused filament fabrication (FFF) parts. Design/methodology/approach A vibrating FFF three-dimensional printer was set up, with which the samples fabricated in different directions were manufactured separately without and with vibration applied. A series of experimental tests, including tensile tests, dynamics tests and scanning electron microscopy (SEM) tests, were performed on these samples to experimentally quantify the effect of applied vibration on their forming quality. Findings It has been found that the applied vibration can significantly increase the tensile strength and plasticity of the samples built in Z-direction, and obviously decrease the orthogonal anisotropy. It can also significantly change the sample’s natural frequency, decrease the resonant response and increase the modal damping ratio, thus improve the anti-vibration capability of FFF samples. In addition, the SEM analysis confirmed that applying vibration into FFF process could improve the forming quality of the fabricated part. Research limitations/implications Future research may be focused on investigating the efficiency of applied vibration in improving the forming quality of parts fabricated by the other additive manufacturing techniques. Practical implications This study helps to improve the reliability of FFF parts and extend the application range of FFF technology. Originality/value A novel method to improve the forming quality of FFF parts is provided and the available information about the performance of dynamics characteristics.
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Yonezawa, Asahi, und Akira Yamada. „Deterioration of the Mechanical Properties of FFF 3D-Printed PLA Structures“. Inventions 6, Nr. 1 (22.12.2020): 1. http://dx.doi.org/10.3390/inventions6010001.
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Poly(lactic acid) (PLA) is a biodegradable polymer material used for the fabrication of objects by fused filament fabrication (FFF) 3D printing. FFF 3D printing technology has been quickly spreading over the past few years. An FFF-3D-printed object is formed from melted polymer extruded from a nozzle layer-by-layer. The mechanical properties of the object, and the changes in those properties as the object degrades, differ from the properties and changes observed in bulk objects. In this study we evaluated FFF-3D-printed objects by uniaxial tensile tests and four-point flexural tests to characterize the changes of three mechanical properties, namely, the maximum stress, elastic modulus, and breaking energy. Eight types of test pieces printed directly by an FFF 3D printer using two scan patterns and two interior fill percentages (IFPs) were tested by the aforesaid methods. The test pieces were immersed in saline and kept in an incubator at 37 °C for 30, 60, or 90 days before the mechanical testing. The changes in the mechanical properties differed largely between the test piece types. In some of the test pieces, transient increases in strength were observed before the immersion degraded the strength. Several of the test piece types were found to have superior specific strength in the tests. The results obtained in this research will be helpful for the design of PLA structures fabricated by FFF 3D printing.
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Chohan, Jasgurpreet Singh, Nitin Mittal, Raman Kumar, Sandeep Singh, Shubham Sharma, Jujhar Singh, Kalagadda Venkateswara Rao, Mozammel Mia, Danil Yurievich Pimenov und Shashi Prakash Dwivedi. „Mechanical Strength Enhancement of 3D Printed Acrylonitrile Butadiene Styrene Polymer Components Using Neural Network Optimization Algorithm“. Polymers 12, Nr. 10 (30.09.2020): 2250. http://dx.doi.org/10.3390/polym12102250.
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Fused filament fabrication (FFF), a portable, clean, low cost and flexible 3D printing technique, finds enormous applications in different sectors. The process has the ability to create ready to use tailor-made products within a few hours, and acrylonitrile butadiene styrene (ABS) is extensively employed in FFF due to high impact resistance and toughness. However, this technology has certain inherent process limitations, such as poor mechanical strength and surface finish, which can be improved by optimizing the process parameters. As the results of optimization studies primarily depend upon the efficiency of the mathematical tools, in this work, an attempt is made to investigate a novel optimization tool. This paper illustrates an optimization study of process parameters of FFF using neural network algorithm (NNA) based optimization to determine the tensile strength, flexural strength and impact strength of ABS parts. The study also compares the efficacy of NNA over conventional optimization tools. The advanced optimization successfully optimizes the process parameters of FFF and predicts maximum mechanical properties at the suggested parameter settings.
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Vidakis, Nectarios, Markos Petousis, Apostolos Korlos, Emmanouil Velidakis, Nikolaos Mountakis, Chrisa Charou und Adrian Myftari. „Strain Rate Sensitivity of Polycarbonate and Thermoplastic Polyurethane for Various 3D Printing Temperatures and Layer Heights“. Polymers 13, Nr. 16 (17.08.2021): 2752. http://dx.doi.org/10.3390/polym13162752.
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In this work, strain rate sensitivity was studied for 3D-printed polycarbonate (PC) and thermoplastic polyurethane (TPU) materials. Specimens were fabricated through fused filament fabrication (FFF) additive manufacturing (AM) technology and were tested at various strain rates. The effects of two FFF process parameters, i.e., nozzle temperature and layer thickness, were also investigated. A wide analysis for the tensile strength (MPa), the tensile modulus of elasticity (MPa), the toughness (MJ/m3) and the strain rate sensitivity index ‘m’ was conducted. Additionally, a morphological analysis was conducted using scanning electron microscopy (SEM) on the side and the fracture area of the specimens. Results from the different strain rates for each material were analyzed, in conjunction with the two FFF parameters tested, to determine their effect on the mechanical response of the two materials. PC and TPU materials exhibited similarities regarding their temperature response at different strain rates, while differences in layer height emerged regarding the appropriate choice for the FFF process. Overall, strain rate had a significant effect on the mechanical response of both materials.
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Avdeev, Artem, Andrey Shvets, Ilya Gushchin, Ivan Torubarov, Aleksey Drobotov, Aleksey Makarov, Aleksander Plotnikov und Yuri Serdobintsev. „Strength Increasing Additive Manufacturing Fused Filament Fabrication Technology, Based on Spiral Toolpath Material Deposition“. Machines 7, Nr. 3 (05.09.2019): 57. http://dx.doi.org/10.3390/machines7030057.
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The paper provides an overview of ways to increase the strength of polymer products obtained by fused filament fabrication (FFF) technology. An algorithm for calculating the spiral toolpaths for the material deposition using multi-axis printing is proposed. The design of the five-axis device for spiral-shaped deposition of the material is shown. The description of the proposed printing method is given. The results of comparative three-point bend and compression tests are presented. The standard samples obtained in the usual way by FFF technology, as well as samples with 2, 4, 6, 8 and 10 reinforcing layers obtained by spiral deposition of the material were investigated. The description of the tests is given, the dependences of the strength of the products on the number of reinforcing layers are obtained. Conclusions about the influence of the layer deposition method on the strength of the products are formulated.
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García-Hernández, Trinitat, Aurora Vicedo-González, Beatriz Sánchez-Nieto, Maite Romero-Expósito und Joan Roselló-Ferrando. „PERIPHERAL SURFACE DOSE FROM A LINEAR ACCELERATOR: RADIOCHROMIC FILM EXPERIMENTAL MEASUREMENTS OF FLATTENING FILTER FREE VERSUS FLATTENED BEAMS“. Radiation Protection Dosimetry 188, Nr. 3 (10.01.2020): 285–98. http://dx.doi.org/10.1093/rpd/ncz286.
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Abstract There is a growing interest in the use of flattening filter free (FFF) beams due to the shorter treatment times. The reduction of head scatter suggests a better radiation protection to radiotherapy patients, considering the expected decrease in peripheral surface dose (PSD). In this work, PSD of flattened (FF) and FFF-photon beams was compared. A radiochromic film calibration method to reduce energy dependence was used. PSD was measured at distances from 2 to 50 cm to the field border for different square field sizes, modifying relevant clinical parameters. Also, clinical breast and prostate stereotactic body radiotherapy (SBRT) plans were studied. For square beams, FFF PSD is lower compared with FF PSD (differences ranging from 3 to 64%) and 10 MV FFF yields to the lowest value, for distances greater than 5 cm. For SBRT plans, near and far away from the field border, there is a reduction of PSD for FFF-beams, but the behavior at intermediate distances should be checked depending on the case.
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Panda, Anton, und Samuel Cehelsky. „WELDING METHODS OF FILAMENTS USED IN FFF/FDM 3D PRINTING TECHNOLOGY“. MM Science Journal 2020, Nr. 4 (11.11.2020): 4062–67. http://dx.doi.org/10.17973/mmsj.2020_11_2020023.
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Korotchenko, A. Yu, D. E. Khilkov, M. V. Tverskoy und A. A. Khilkova. „Research of 3D Printing Modes of Feedstock for Metal Injection Molding“. Materials Science Forum 992 (Mai 2020): 461–66. http://dx.doi.org/10.4028/www.scientific.net/msf.992.461.
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In this work, to reduce the cost of production of parts using injection molding metal technology (MIM technology), it is proposed to use additive technologies (AT) for the manufacture of green parts. The use of AT allows us to abandon expensive molds and expand the field of use of the MIM of technology in single and small-scale production. For manufacture of green parts, the technology of manufacturing fused filament (Fused Filament Fabrication – FFF) is offered. The original composition of the metal powder mix (feedstock) and the filament manufacturing modes for 3D printing have been developed for the FFF technology. The cost of filament is much lower than its analogs. The factors affecting the print quality of green part are considered. All factors are divided into two groups depending on the possibility of their change during printing. The research of the influence of the coefficient filament supply on the geometry of green parts during 3D printing is presented.
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Cano, Santiago, Tanja Lube, Philipp Huber, Alberto Gallego, Juan Alfonso Naranjo, Cristina Berges, Stephan Schuschnigg et al. „Influence of the Infill Orientation on the Properties of Zirconia Parts Produced by Fused Filament Fabrication“. Materials 13, Nr. 14 (15.07.2020): 3158. http://dx.doi.org/10.3390/ma13143158.
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The fused filament fabrication (FFF) of ceramics enables the additive manufacturing of components with complex geometries for many applications like tooling or prototyping. Nevertheless, due to the many factors involved in the process, it is difficult to separate the effect of the different parameters on the final properties of the FFF parts, which hinders the expansion of the technology. In this paper, the effect of the fill pattern used during FFF on the defects and the mechanical properties of zirconia components is evaluated. The zirconia-filled filaments were produced from scratch, characterized by different methods and used in the FFF of bending bars with infill orientations of 0°, ±45° and 90° with respect to the longest dimension of the specimens. Three-point bending tests were conducted on the specimens with the side in contact with the build platform under tensile loads. Next, the defects were identified with cuts in different sections. During the shaping by FFF, pores appeared inside the extruded roads due to binder degradation and or moisture evaporation. The changes in the fill pattern resulted in different types of porosity and defects in the first layer, with the latter leading to earlier fracture of the components. Due to these variations, the specimens with the 0° infill orientation had the lowest porosity and the highest bending strength, followed by the specimens with ±45° infill orientation and finally by those with 90° infill orientation.
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Sovaiala, Gheorghe, Alexandru-Polifron Chirita, Sava Anghel und DragoȘ Manea. „Rapid Prototyping of the Injection Device Piston Used for Fertigation Using 3D Printing Technology“. Materiale Plastice 56, Nr. 4 (30.12.2019): 825–30. http://dx.doi.org/10.37358/mp.19.4.5272.
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The article presents the process by which, with the help of 3D printing technology, the piston of the differential injection device was produced using ABS material. It was made with fused filament fabrication (FFF) technology, and the smoothing process was used to improve the surface quality. The piston is part of a complex equipment for underground fertilization of agricultural crops.
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Lüchtenborg, Jörg, Felix Burkhardt, Julian Nold, Severin Rothlauf, Christian Wesemann, Stefano Pieralli, Gregor Wemken, Siegbert Witkowski und Benedikt C. Spies. „Implementation of Fused Filament Fabrication in Dentistry“. Applied Sciences 11, Nr. 14 (13.07.2021): 6444. http://dx.doi.org/10.3390/app11146444.
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Additive manufacturing is becoming an increasingly important technique for the production of dental restorations and assistive devices. The most commonly used systems are based on vat polymerization, e.g., stereolithography (SLA) and digital light processing (DLP). In contrast, fused filament fabrication (FFF), also known under the brand name fused deposition modeling (FDM), is rarely applied in the dental field. This might be due to the reduced accuracy and resolution of FFF compared to vat polymerization. However, the use of FFF in the dental sector seems very promising for in-house production since it presents a cost-effective and straight forward method. The manufacturing of nearly ready-to-use parts with only minimal post-processing can be considered highly advantageous. Therefore, the objective was to implement FFF in a digital dental workflow. The present report demonstrates the production of surgical guides for implant insertion by FFF. Furthermore, a novel approach using a temperature-sensitive filament for bite registration plates holds great promise for a simplified workflow. In combination with a medical-grade filament, a multi-material impression tray was printed for optimized impression taking of edentulous patients. Compared to the conventional way, the printed thermoplastic material is pleasant to model and can allow clean and fast work on the patient.
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Mrowka, Maciej, Machoczek Machoczek, Malgorzata Szymiczek, Przemyslaw Gagol, Slawomir Duda und Lukasz Marcoll. „Surface treatment of incrementally produced components in FFF (Fused Filament Fabrication) technology“. Polimery 65, Nr. 01 (Januar 2020): 51–59. http://dx.doi.org/10.14314/polimery.2020.1.7.
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Mashayekhi, Fatemeh, Julien Bardon, Vincent Berthé, Henri Perrin, Stephan Westermann und Frédéric Addiego. „Fused Filament Fabrication of Polymers and Continuous Fiber-Reinforced Polymer Composites: Advances in Structure Optimization and Health Monitoring“. Polymers 13, Nr. 5 (04.03.2021): 789. http://dx.doi.org/10.3390/polym13050789.
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3D printed neat thermoplastic polymers (TPs) and continuous fiber-reinforced thermoplastic composites (CFRTPCs) by fused filament fabrication (FFF) are becoming attractive materials for numerous applications. However, the structure of these materials exhibits interfaces at different scales, engendering non-optimal mechanical properties. The first part of the review presents a description of these interfaces and highlights the different strategies to improve interfacial bonding. The actual knowledge on the structural aspects of the thermoplastic matrix is also summarized in this contribution with a focus on crystallization and orientation. The research to be tackled to further improve the structural properties of the 3D printed materials is identified. The second part of the review provides an overview of structural health monitoring technologies relying on the use of fiber Bragg grating sensors, strain gauge sensors and self-sensing. After a brief discussion on these three technologies, the needed research to further stimulate the development of FFF is identified. Finally, in the third part of this contribution the technology landscape of FFF processes for CFRTPCs is provided, including the future trends.
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Chalissery, Dilip, Thorsten Pretsch, Sarah Staub und Heiko Andrä. „Additive Manufacturing of Information Carriers Based on Shape Memory Polyester Urethane“. Polymers 11, Nr. 6 (05.06.2019): 1005. http://dx.doi.org/10.3390/polym11061005.
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Shape memory polymers (SMPs) are stimuli-responsive materials, which are able to retain an imposed, temporary shape and recover the initial, permanent shape through an external stimulus like heat. In this work, a novel manufacturing method is introduced for thermoresponsive quick response (QR) code carriers, which originally were developed as anticounterfeiting technology. Motivated by the fact that earlier manufacturing processes were sometimes too time-consuming for production, filaments of a polyester urethane (PEU) with and without dye were extruded and processed into QR code carriers using fused filament fabrication (FFF). Once programmed, the distinct shape memory properties enabled a heating-initiated switching from non-decodable to machine-readable QR codes. The results demonstrate that FFF constitutes a promising additive manufacturing technology to create complex, filigree structures with adjustable horizontal and vertical print resolution and, thus, an excellent basis to realize further technically demanding application concepts for shape memory polymers.
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Sharma, Neha, Soheila Aghlmandi, Shuaishuai Cao, Christoph Kunz, Philipp Honigmann und Florian M. Thieringer. „Quality Characteristics and Clinical Relevance of In-House 3D-Printed Customized Polyetheretherketone (PEEK) Implants for Craniofacial Reconstruction“. Journal of Clinical Medicine 9, Nr. 9 (31.08.2020): 2818. http://dx.doi.org/10.3390/jcm9092818.
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Additive manufacturing (AM) of patient-specific implants (PSIs) is gradually moving towards in-house or point-of-care (POC) manufacturing. Polyetheretherketone (PEEK) has been used in cranioplasty cases as a reliable alternative to other alloplastic materials. As only a few fused filament fabrication (FFF) printers are suitable for in-house manufacturing, the quality characteristics of the implants fabricated by FFF technology are still under investigated. This paper aimed to investigate PEEK PSIs fabricated in-house for craniofacial reconstruction, discussing the key challenges during the FFF printing process. Two exemplary cases of class III (Group 1) and class IV (Group 2) craniofacial defects were selected for the fabrication of PEEK PSIs. Taguchi’s L9 orthogonal array was selected for the following nonthermal printing process parameters, i.e., layer thickness, infill rate, number of shells, and infill pattern, and an assessment of the dimensional accuracy of the fabricated implants was made. The root mean square (RMS) values revealed higher deviations in Group 1 PSIs (0.790 mm) compared to Group 2 PSIs (0.241 mm). Horizontal lines, or the characteristic FFF stair-stepping effect, were more perceptible across the surface of Group 1 PSIs. Although Group 2 PSIs revealed no discoloration, Group 1 PSIs displayed different zones of crystallinity. These results suggest that the dimensional accuracy of PSIs were within the clinically acceptable range; however, attention must be paid towards a requirement of optimum thermal management during the printing process to fabricate implants of uniform crystallinity.
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Damon, James, Stefan Dietrich, Sasidhar Gorantla, Uwe Popp, Brando Okolo und Volker Schulze. „Process porosity and mechanical performance of fused filament fabricated 316L stainless steel“. Rapid Prototyping Journal 25, Nr. 7 (12.08.2019): 1319–27. http://dx.doi.org/10.1108/rpj-01-2019-0002.
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Purpose This study aims to investigate the correlation between build orientation characteristics, part porosity and mechanical properties of the fused filament fabrication (FFF) process to provide insight into pore formation mechanisms and to establish guidelines for optimal process configurations. Design/methodology/approach Micro computed tomography and metallographic sections provide the basis for a correlation between porosity and extrusion path. Using the correlations found in this study, the way to improve printing strategies and filament properties can be deduced directly from an analysis of the print path and the final influence on mechanical performance. Findings With metal-FFF 3D printing technology, near-dense parts (0.5 Vol.%) can be fabricated. The pore architecture is strongly connected to the build direction and print strategy with parallel, elongated pore channels. Mechanical values of FFF samples are similar to metal injection-molded (MIM) parts, except the elongation to fracture. The high difference of yield strength of sintered samples compared to laser powder bed fusion (LPBF) samples can be attributed to the finer grains and a Hall–Petch hardening effect. The conclusions derived from this study are that the presented process is capable of producing comparable part qualities compared to MIM samples, with higher build rates in comparison to LPBF processes. Originality/value 316L stainless steel was successfully manufactured via FFF. This paper also addresses the effects of scanning strategies on the resulting porosity and proposes improvements to reduce residual porosity, thus increasing the mechanical performance in the future.
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Shaqour, Bahaa, Aseel Samaro, Bart Verleije, Koen Beyers, Chris Vervaet und Paul Cos. „Production of Drug Delivery Systems Using Fused Filament Fabrication: A Systematic Review“. Pharmaceutics 12, Nr. 6 (05.06.2020): 517. http://dx.doi.org/10.3390/pharmaceutics12060517.
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Fused filament fabrication (FFF) 3D printing technology is widely used in many fields. For almost a decade, medical researchers have been exploring the potential use of this technology for improving the healthcare sector. Advances in personalized medicine have been more achievable due to the applicability of producing drug delivery devices, which are explicitly designed based on patients’ needs. For the production of these devices, a filament—which is the feedstock for the FFF 3D printer—consists of a carrier polymer (or polymers) and a loaded active pharmaceutical ingredient (API). This systematic review of the literature investigates the most widely used approaches for producing drug-loaded filaments. It also focusses on several factors, such as the polymeric carrier and the drug, loading capacity and homogeneity, processing conditions, and the intended applications. This review concludes that the filament preparation method has a significant effect on both the drug homogeneity within the polymeric carrier and drug loading efficiency.
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Vaganov, A. V., A. M. Makarov, A. V. Maloletov und E. A. Dyachenko. „RESEARCH SPECIFIC TIME OF 3D PRINTING“. IZVESTIA VOLGOGRAD STATE TECHNICAL UNIVERSITY, Nr. 1(248) (27.01.2021): 50–52. http://dx.doi.org/10.35211/1990-5297-2021-1-248-50-52.
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A study of the specific time of 3D printing using the FFF technology of one gram of material is being carried out. It describes the methodology of the study, using software, and configure it in a study, an analysis of the data and the final results.
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Cuan-Urquizo, Enrique, Eduardo Barocio, Viridiana Tejada-Ortigoza, R. Pipes, Ciro Rodriguez und Armando Roman-Flores. „Characterization of the Mechanical Properties of FFF Structures and Materials: A Review on the Experimental, Computational and Theoretical Approaches“. Materials 12, Nr. 6 (18.03.2019): 895. http://dx.doi.org/10.3390/ma12060895.
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The increase in accessibility of fused filament fabrication (FFF) machines has inspired the scientific community to work towards the understanding of the structural performance of components fabricated with this technology. Numerous attempts to characterize and to estimate the mechanical properties of structures fabricated with FFF have been reported in the literature. Experimental characterization of printed components has been reported extensively. However, few attempts have been made to predict properties of printed structures with computational models, and a lot less work with analytical approximations. As a result, a thorough review of reported experimental characterization and predictive models is presented with the aim of summarizing applicability and limitations of those approaches. Finally, recommendations on practices for characterizing printed materials are given and areas that deserve further research are proposed.
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Stano, Gianni, Luca Arleo und Gianluca Percoco. „Additive Manufacturing for Soft Robotics: Design and Fabrication of Airtight, Monolithic Bending PneuNets with Embedded Air Connectors“. Micromachines 11, Nr. 5 (09.05.2020): 485. http://dx.doi.org/10.3390/mi11050485.
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Air tightness is a challenging task for 3D-printed components, especially for fused filament fabrication (FFF), due to inherent issues, related to the layer-by-layer fabrication method. On the other hand, the capability of 3D print airtight cavities with complex shapes is very attractive for several emerging research fields, such as soft robotics. The present paper proposes a repeatable methodology to 3D print airtight soft actuators with embedded air connectors. The FFF process has been optimized to manufacture monolithic bending PneuNets (MBPs), an emerging class of soft robots. FFF has several advantages in soft robot fabrication: (i) it is a fully automated process which does not require manual tasks as for molding, (ii) it is one of the most ubiquitous and inexpensive (FFF 3D printers costs < $200) 3D-printing technologies, and (iii) more materials can be used in the same printing cycle which allows embedding of several elements in the soft robot body. Using commercial soft filaments and a dual-extruder 3D printer, at first, a novel air connector which can be easily embedded in each soft robot, made via FFF technology with a single printing cycle, has been fabricated and tested. This new embedded air connector (EAC) prevents air leaks at the interface between pneumatic pipe and soft robot and replaces the commercial air connections, often origin of leakages in soft robots. A subsequent experimental study using four different shapes of MBPs, each equipped with EAC, showed the way in which different design configurations can affect bending performance. By focusing on the best performing shape, among the tested ones, the authors studied the relationship between bending performance and air tightness, proving how the Design for Additive Manufacturing approach is essential for advanced applications involving FFF. In particular, the relationship between chamber wall thickness and printing parameters has been analyzed, the thickness of the walls has been studied from 1.6 to 1 mm while maintaining air tightness and improving the bending angle by 76.7% under a pressure of 4 bar. It emerged that the main printing parameter affecting chamber wall air tightness is the line width that, in conjunction with the wall thickness, can ensure air tightness of the soft actuator body.
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Terekhina, Svetlana, Innokentiy Skornyakov, Tatiana Tarasova und Sergei Egorov. „Effects of the Infill Density on the Mechanical Properties of Nylon Specimens Made by Filament Fused Fabrication“. Technologies 7, Nr. 3 (16.08.2019): 57. http://dx.doi.org/10.3390/technologies7030057.
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Additive manufacturing of polymer products over the past decade has become widespread in various areas of industry. Using the fused filament fabrication (FFF) method, one of the most technologically simple methods of additive manufacturing, it is possible to produce parts from a large number of different materials, including wear-resistant nylon. The novelty of the work is properties investigation of ±45° filling configuration with different filling degree for nylon, as well as calculating the effect of infill on the strength characteristics, excluding the shell. This article reflects the process of manufacturing samples from nylon using FFF technology with various internal topologies, as well as tensile tests. The analysis of the obtained results is performed and the relationship between the structure of the sample and the limit of its strength is established. To calculate real filling degree and the effect of internal filling on the strength characteristics of the specimen, it is proposed to use a method based on the geometric and mass parameters. The FFF method is promising for developing methods for producing a composite material. The results of this article can be useful in choosing the necessary manufacturing parameters.
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Koprnicky, Jan, Jiří Šafka und Michal Ackermann. „Using of 3D Printing Technology in Low Cost Prosthetics“. Materials Science Forum 919 (April 2018): 199–206. http://dx.doi.org/10.4028/www.scientific.net/msf.919.199.
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The 3D printing technology used for final production of upper limb prostheses is the topicof this article. It focuses on different 3D printing technologies and testing of different thermoplasticmaterials. As the testing object an index finger of HACKberry open source myoelectric bionic handwas used. This part was 3D printed by using of different printing technologies (FFF/FDM, SLA, SLS,PolyJet), and different materials (PLA, ABS, PC-ABS, Though, etc.), and different strategies (heightof layers). The fingers were mechanically tested to simulate flexion in a tip pinch grip. At the endof this paper results of this research and testing is summarized, and optimal material, technology andstrategies of parts production is highlighted.
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Xiao, Xinyi, Byeong-Min Roh und Feng Zhu. „Strength Enhancement in Fused Filament Fabrication via the Isotropy Toolpath“. Applied Sciences 11, Nr. 13 (30.06.2021): 6100. http://dx.doi.org/10.3390/app11136100.
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The fused filament fabrication (FFF) process deposits thermoplastic material in a layer-by-layer manner, expanding the design space and manufacturing capability compared with traditional manufacturing. However, the FFF process is inherently directional as the material is deposited in a layer-wise manner. Therefore, the in-plane material cannot reach the isotropy character when performing the tensile test. This would cause the strength of the print components to vary based on the different process planning selections (building orientation, toolpath pattern). The existing toolpaths, primarily used in the FFF process, are linear, zigzag, and contour toolpaths, which always accumulate long filaments and are unidirectional. Thus, this would create difficulties in improving the mechanical strength from the existing toolpath strategies due to the material in-plane anisotropy. In this paper, an in-plane isotropy toolpath pattern is generated to enhance the mechanical strength in the FFF process. The in-plane isotropy can be achieved through continuous deposition while maintaining randomized distribution within a layer. By analyzing the tensile strength on the specimens made by traditional in-plane anisotropy toolpath and the proposed in-plane isotropy toolpath, our results suggest that the mechanical strength can be reinforced by at least 20% using our proposed toolpath strategy in extrusion-based additive manufacturing.
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Molnar, Ivan, David Michal, Stefan Simon, Ladislav Morovic und Peter Kostal. „Design and manufacture of life size human model using material extrusion and vat photopolymerization additive processes“. MATEC Web of Conferences 299 (2019): 01010. http://dx.doi.org/10.1051/matecconf/201929901010.
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Nowadays, Additive Manufacturing (AM) is increasingly being used in various fields of medicine. Using Material Extrusion additive process – Fused Filament Fabrication (FFF) method are produced 3D models of organs or body parts designed for preoperative planning, individual prosthetic and orthopaedic appliances and others. The Vat Photopolymerization additive process – Stereolithography (SLA) method is used to produce precision hearing aids, wearable assist devices, prosthetics, orthotics and so on. The content of the article describes the process of designing and manufacturing the life size human model to show the possibilities and advantages of using selected additive methods in the field of medicine and thus pointing out the versatility of using the AM technology on a concrete example. The aim of thisarticle is to provide an up-to-date practical application of FFF and SLA additive methods in the fast-growing field of AM and to present to the reader a specific example of the use of AM with the idea of raising a better general understanding and supporting research into the use of AM technology in medicine.
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Eleftheriadis, Georgios K., Christos S. Katsiotis, Natalja Genina, Johan Boetker, Jukka Rantanen und Dimitrios G. Fatouros. „Manufacturing of hybrid drug delivery systems by utilizing the fused filament fabrication (FFF) technology“. Expert Opinion on Drug Delivery 17, Nr. 8 (08.06.2020): 1063–68. http://dx.doi.org/10.1080/17425247.2020.1776260.
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Kuznetsov, Vladimir E., Azamat G. Tavitov, Oleg D. Urzhumtsev, Mikhail V. Mikhalin und Alexander I. Moiseev. „Hardware Factors Influencing Strength of Parts Obtained by Fused Filament Fabrication“. Polymers 11, Nr. 11 (13.11.2019): 1870. http://dx.doi.org/10.3390/polym11111870.
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The current paper investigates the influence of the hardware setup and parameters of a 3D printing process on the resulting sample strength obtained through fused filament fabrication (FFF) technology. Three-point bending was chosen as the strength measure for samples printed with the long side oriented along the Z-axis. A single CAD model was converted into NC-programs through the same slicing software to be run on five different desktop FFF 3D printers with filament of the same brand and color. For all the printers, the same ranges of layer thickness values from 0.1 to 0.3 mm and feed rates from 25 to 75 mm/s were planned to be varied. The first four machines considered in the study were off the shelf devices available on the market, and the fifth was a quick prototype of a desktop machine design based on the analysis of pros and cons of the four machines considered. The results of the study show that the hardware setup of a desktop 3D printer can drastically change the influence of basic technological parameters such as feed rate and layer thickness on the interlayer bonding. This means that many of the conclusions drawn from previous studies connecting the technological parameters of the FFF process with the mechanical performance of parts and samples may only be correct for specific hardware setups.
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Grigore, Lucian Stefanita, Amado-George Stefan, Octavian Orban und Ioana-Raluca Adochiei. „Considerations on the Plastic Structure of a UAV Payload Made by 3D Printing Technology“. Materiale Plastice 57, Nr. 4 (06.01.2021): 21–33. http://dx.doi.org/10.37358/mp.20.4.5403.
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With the development of unmanned aerial vehicle (UAV) systems for a multitude of real-time applications, 3D printing technologies have been developed to make thermoplastic structures by fusing filament Fused Deposition Modeling (FDM) or Fused Filament Fabrication (FFF). However, we consider that the realization of new technologies of experimental models / technological demonstrators / prototypes becomes profitable by using 3D printing technologies. The main aim of the paper is to highlight how the use of three types of materials, which are processed differently, influences the Von Mises stresses of the payload used for a UAV, with the mission of photographing and filming from high altitude.
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Tosto, Claudio, Jacopo Tirillò, Fabrizio Sarasini und Gianluca Cicala. „Hybrid Metal/Polymer Filaments for Fused Filament Fabrication (FFF) to Print Metal Parts“. Applied Sciences 11, Nr. 4 (05.02.2021): 1444. http://dx.doi.org/10.3390/app11041444.
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The exploitation of mechanical properties and customization possibilities of 3D printed metal parts usually come at the cost of complex and expensive equipment. To address this issue, hybrid metal/polymer composite filaments have been studied allowing the printing of metal parts by using the standard Fused Filament Fabrication (FFF) approach. The resulting hybrid metal/polymer part, the so called “green”, can then be transformed into a dense metal part using debinding and sintering cycles. In this work, we investigated the manufacturing and characterization of green and sintered parts obtained by FFF of two commercial hybrid metal/polymer filaments, i.e., the Ultrafuse 316L by BASF and the 17-4 PH by Markforged. The Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectrometry (EDS) analyses of the mesostructure highlighted incomplete raster bonding and voids like those observed in conventional FFF-printed polymeric structures despite the sintering cycle. A significant role in the tensile properties was played by the building orientation, with samples printed flatwise featuring the highest mechanical properties, though lower than those achievable with standard metal additive manufacturing techniques.
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Liao, Yuhan, Chang Liu, Bartolomeo Coppola, Giuseppina Barra, Luciano Di Maio, Loredana Incarnato und Khalid Lafdi. „Effect of Porosity and Crystallinity on 3D Printed PLA Properties“. Polymers 11, Nr. 9 (12.09.2019): 1487. http://dx.doi.org/10.3390/polym11091487.
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Additive manufacturing (AM) is a promising technology for the rapid tooling and fabrication of complex geometry components. Among all AM techniques, fused filament fabrication (FFF) is the most widely used technique for polymers. However, the consistency and properties control of the FFF product remains a challenging issue. This study aims to investigate physical changes during the 3D printing of polylactic acid (PLA). The correlations between the porosity, crystallinity and mechanical properties of the printed parts were studied. Moreover, the effects of the build-platform temperature were investigated. The experimental results confirmed the anisotropy of printed objects due to the occurrence of orientation phenomena during the filament deposition and the formation both of ordered and disordered crystalline forms (α and δ, respectively). A heat treatment post-3D printing was proposed as an effective method to improve mechanical properties by optimizing the crystallinity (transforming the δ form into the α one) and overcoming the anisotropy of the 3D printed object.
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Brząkalski, Dariusz, Bogna Sztorch, Miłosz Frydrych, Daria Pakuła, Kamil Dydek, Rafał Kozera, Anna Boczkowska, Bogdan Marciniec und Robert E. Przekop. „Limonene Derivative of Spherosilicate as a Polylactide Modifier for Applications in 3D Printing Technology“. Molecules 25, Nr. 24 (12.12.2020): 5882. http://dx.doi.org/10.3390/molecules25245882.
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The first report of using limonene derivative of a spherosilicate as a modifier of polylactide used for 3D printing and injection moulding is presented. The paper presents the use of limonene-functionalized spherosilicate derivative as a functional additive. The study compared the material characteristics of polylactide modified with SS-Limonene (0.25–5.0% w/w) processed with traditional injection moulding and 3D printing (FFF, FDM). A significant improvement in the processing properties concerning rheology, inter-layer adhesion, and mechanical properties was achieved, which translated into the quality of the print and reduction of waste production. Moreover, the paper describes the elementary stages of thermal transformations of the obtained hybrid systems.
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Spoerk, Martin, Florian Arbeiter, Ivan Raguž, Clemens Holzer und Joamin Gonzalez-Gutierrez. „Mechanical Recyclability of Polypropylene Composites Produced by Material Extrusion-Based Additive Manufacturing“. Polymers 11, Nr. 8 (07.08.2019): 1318. http://dx.doi.org/10.3390/polym11081318.
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Due to a lack of long-term experience with burgeoning material extrusion-based additive manufacturing technology, also known as fused filament fabrication (FFF), considerable amounts of expensive material will continue to be wasted until a defect-free 3D-printed component can be finalized. In order to lead this advanced manufacturing technique toward cleaner production and to save costs, this study addresses the ability to remanufacture a wide range of commercially available filaments. Most of them either tend to degrade by chain scission or crosslinking. Only polypropylene (PP)-based filaments appear to be particularly thermally stable and therefore suitable for multiple remanufacturing sequences. As the extrusion step exerts the largest influence on the material in terms of temperature and shear load, this study focused on the morphological, rheological, thermal, processing, tensile, and impact properties of a promising PP composite in the course of multiple consecutive extrusions as well as the impact of additional heat stabilizers. Even after 15 consecutive filament extrusions, the stabilized additively manufactured PP composite revealed an unaltered morphology and therefore the same tensile and impact strength as the initial material. As the viscosity of the material of the 15th extrusion was nearly identical to that of the 1st extrusion sequence, the processability both in terms of extrusion and FFF was outstanding, despite the tremendous amount of shear and thermal stress that was undergone. The present work provides key insights into one possible step toward more sustainable production through FFF.
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Gradwohl, Marion, Feng Chai, Julien Payen, Pierre Guerreschi, Philippe Marchetti und Nicolas Blanchemain. „Effects of Two Melt Extrusion Based Additive Manufacturing Technologies and Common Sterilization Methods on the Properties of a Medical Grade PLGA Copolymer“. Polymers 13, Nr. 4 (14.02.2021): 572. http://dx.doi.org/10.3390/polym13040572.
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Although bioabsorbable polymers have garnered increasing attention because of their potential in tissue engineering applications, to our knowledge there are only a few bioabsorbable 3D printed medical devices on the market thus far. In this study, we assessed the processability of medical grade Poly(lactic-co-glycolic) Acid (PLGA)85:15 via two additive manufacturing technologies: Fused Filament Fabrication (FFF) and Direct Pellet Printing (DPP) to highlight the least destructive technology towards PLGA. To quantify PLGA degradation, its molecular weight (gel permeation chromatography (GPC)) as well as its thermal properties (differential scanning calorimetry (DSC)) were evaluated at each processing step, including sterilization with conventional methods (ethylene oxide, gamma, and beta irradiation). Results show that 3D printing of PLGA on a DPP printer significantly decreased the number-average molecular weight (Mn) to the greatest extent (26% Mn loss, p < 0.0001) as it applies a longer residence time and higher shear stress compared to classic FFF (19% Mn loss, p < 0.0001). Among all sterilization methods tested, ethylene oxide seems to be the most appropriate, as it leads to no significant changes in PLGA properties. After sterilization, all samples were considered to be non-toxic, as cell viability was above 70% compared to the control, indicating that this manufacturing route could be used for the development of bioabsorbable medical devices. Based on our observations, we recommend using FFF printing and ethylene oxide sterilization to produce PLGA medical devices.
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Buj-Corral, Irene, Xavier Sánchez-Casas und Carmelo J. Luis-Pérez. „Analysis of AM Parameters on Surface Roughness Obtained in PLA Parts Printed with FFF Technology“. Polymers 13, Nr. 14 (20.07.2021): 2384. http://dx.doi.org/10.3390/polym13142384.
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Fused filament fabrication (FFF) 3D printing technology allows very complex parts to be obtained at a relatively low cost and in reduced manufacturing times. In the present work, the effect of main 3D printing parameters on roughness obtained in curved surfaces is addressed. Polylactic acid (PLA) hemispherical cups were printed with a shape similar to that of the acetabular part of the hip prostheses. Different experiments were performed according to a factorial design of experiments, with nozzle diameter, temperature, layer height, print speed and extrusion multiplier as variables. Different roughness parameters were measured—Ra, Rz, Rku, Rsk—both on the outer surface and on the inner surface of the parts. Arithmetical mean roughness value Ra and greatest height of the roughness profile Rz are usually employed to compare the surface finish among different manufacturing processes. However, they do not provide information about the shape of the roughness profile. For this purpose, in the present work kurtosis Rku and skewness Rsk were used. If the height distribution in a roughness profile follows a normal law, the Rku parameter will take a value of 3. If the profile distribution is symmetrical, the Rsk parameter will take a value of 0. Adaptive neural fuzzy inference system (ANFIS) models were obtained for each response. Such models are often employed to model different manufacturing processes, but their use has not yet been extended to 3D printing processes. All roughness parameters studied depended mainly on layer height, followed by nozzle diameter. In the present work, as a general trend, Rsk was close to but lower than 0, while Rku was slightly lower than 3. This corresponds to slightly higher valleys than peaks, with a rounded height distribution to some degree.
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Martín, María Jesús, Juan Antonio Auñón und Francisco Martín. „Influence of Infill Pattern on Mechanical Behavior of Polymeric and Composites Specimens Manufactured Using Fused Filament Fabrication Technology“. Polymers 13, Nr. 17 (31.08.2021): 2934. http://dx.doi.org/10.3390/polym13172934.
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This paper presents the results of a comparative evaluation of the tensile strength behaviors of parts obtained by additive manufacturing using fused filament fabrication (FFF) technology. The study investigated the influences of the deposition printing parameters for both polymers and fiber-reinforced polymers. Polymeric materials that are widely used in FFF were selected, including acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), and nylon. Carbon and glass continuous fibers were used to reinforce the nylon matrix in composite materials. The study utilized two manufacturing methods. Polymers were manufactured using an Ultimaker 2 Extended+ device and the fiber-reinforced polymer specimens were obtained using a Markforged Mark Two printer. The entire set of specimens was eventually subjected to destructive monoaxial tensile tests to measure their responses. The main goal of this study was to estimate the effect of the different infill patterns applied (zig-zag, concentric, and four different orientations lines) on the mechanical properties of pure thermoplastic materials and reinforced polymers. Results show a spectacular increase in the tensile stress at break, which for polymers reaches an average value of 27.53 MPa compared to 94.51 MPa in the case of composites (increase of 70.87%). A similar increase occurs in the case of tensile stress at yield with values of 31.87 MPa and 105.98 MPa, respectively, which represents an increase of 69.93%. The influence of the infill of the fiber is decisive, reaching, in the 0-0 arrangement, mean values of 220.18 MPa for tensile stress at break and 198.26 MPa for tensile stress at yield.
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Pepelnjak, Tomaž, Ako Karimi, Andraž Maček und Nikolaj Mole. „Altering the Elastic Properties of 3D Printed Poly-Lactic Acid (PLA) Parts by Compressive Cyclic Loading“. Materials 13, Nr. 19 (08.10.2020): 4456. http://dx.doi.org/10.3390/ma13194456.
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In designing high-performance, lightweight components, cellular structures are one of the approaches to be considered. The present study aimed to analyze the effect of the infill line distance of 3D printed circular samples on their compressive elastic behavior. Lightweight cellular poly-lactic acid (PLA) samples with a triangular infill pattern were exposed to cyclic compressive loading and their stiffness was investigated. PLA is one of the most commonly used thermoplastic materials in additive manufacturing using the fused filament fabrication (FFF) process. Cylindrical samples with a diameter of 11.42 mm and a height of 10 mm were printed using FFF technology with two different infill line distances (1.6 mm and 2.4 mm). Comparing the nominal compressive stress-nominal strain curves under cyclic loading showed that the first cycle response was significantly different with respect to the subsequent ones. Furthermore, an analysis of the dependence of the modulus of elasticity on the effects of cyclic loading was performed. It was found that through elastic deformation, and combined elastic and plastic deformation, the samples’ properties such as stiffness could be altered.
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Pellegrino, J., S. Wright, J. Ranvill und G. Amy. „Predicting membrane flux decline from complex mixtures using flow-field flow fractionation measurements and semi-empirical theory“. Water Science and Technology 51, Nr. 6-7 (01.03.2005): 85–92. http://dx.doi.org/10.2166/wst.2005.0625.
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Flow-Field Flow Fractionation (Fl-FFF) is an idealization of the cross flow membrane filtration process in that, (1) the filtration flux and crossflow velocity are constant from beginning to end of the device, (2) the process is a relatively well-defined laminar-flow hydrodynamic condition, and (3) the solutes are introduced as a pulse-input that spreads due to interactions with each other and the membrane in the dilute-solution limit. We have investigated the potential for relating Fl-FFF measurements to membrane fouling. An advection-dispersion transport model was used to provide ‘ideal’ (defined as spherical, non-interacting solutes) solute residence time distributions (RTDs) for comparison with ‘real’ RTDs obtained experimentally at different cross-field velocities and solution ionic strength. An RTD moment analysis based on a particle diameter probability density function was used to extract “effective” characteristic properties, rather than uniquely defined characteristics, of the standard solute mixture. A semi-empirical unsteady-state, flux decline model was developed that uses solute property parameters. Three modes of flux decline are included: (1) concentration polarization, (2) cake buildup, and (3) adsorption on/in pores, We have used this model to test the hypothesis—that an analysis of a residence time distribution using Fl-FFF can describe ‘effective’ solute properties or indices that can be related to membrane flux decline in crossflow membrane filtration. Constant flux filtration studies included the changes of transport hydrodynamics (solvent flux to solute back diffusion (J/k) ratios), solution ionic strength, and feed water composition for filtration using a regenerated cellulose ultrafiltration membrane. Tests of the modeling hypothesis were compared with experimental results from the filtration measurements using several correction parameters based on the mean and variance of the solute RTDs. The corrections used to modify the boundary layer mass transfer coefficient and the specific resistance of cake or adsorption layers demonstrated that RTD analysis is potentially useful technique to describe colloid properties but requires improvements.
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Kluczyński, Janusz, Lucjan Śnieżek, Alexander Kravcov, Krzysztof Grzelak, Pavel Svoboda, Ireneusz Szachogłuchowicz, Ondřej Franek, Nikolaj Morozov, Janusz Torzewski und Petr Kubeček. „The Examination of Restrained Joints Created in the Process of Multi-Material FFF Additive Manufacturing Technology“. Materials 13, Nr. 4 (18.02.2020): 903. http://dx.doi.org/10.3390/ma13040903.
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The paper is focused on the examination of the internal quality of joints created in a multi-material additive manufacturing process. The main part of the work focuses on experimental production and non-destructive testing of restrained joints of modified PLA (polylactic acid) and ABS (Acrylonitrile butadiene styrene) three-dimensional (3D)-printed on RepRap 3D device that works on the “open source” principle. The article presents the outcomes of a non-destructive materials test in the form of the data from the Laser Amplified Ultrasonography, microscopic observations of the joints area and tensile tests of the specially designed samples. The samples with designed joints were additively manufactured of two materials: Specially blended PLA (Market name—PLA Tough) and conventionally made ABS. The tests are mainly focused on the determination of the quality of material connection in the joints area. Based on the results obtained, the samples made of two materials were compared in the end to establish which produced material joint is stronger and have a lower amount of defects.
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Савченко, Б. М., Н. В. Сова, Б. С. Дебелий, Р. Ш. Іскандаров, О. О. Слепцов und Т. А. Поліщук. „АДИТИВНЕ ФОРМУВАННЯ ЕЛАСТИЧНИХ ВИРОБІВ З ПВХ ПЛАСТИЗОЛЮ“. Bulletin of the Kyiv National University of Technologies and Design. Technical Science Series 142, Nr. 1 (03.06.2020): 86–93. http://dx.doi.org/10.30857/1813-6796.2020.1.8.
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Development and testing of the technology of additive formation of elastic and soft products. The tensile strength and elongation at break for all the studied samples were determined according to ISO 527, the density of the samples according to PN-EN ISO 1183-1, the melt flow rate according to ISO 1133: 2005, the Shore A hardness according to ISO 868. The technology of additive manufacturing of soft and elastic products from liquid consumables has been created. The initial raw material for the formation of objects is the liquid composition of PVC, which can be transformed from the liquid state of plastisol to elastic plastic part or article. The created technology allows to create products of complex geometric shape with a hardness on the Shore scale of 5 to 90 units. The developed technology allows to create products from composite materials and foam based on PVC and can be implemented on equipment for FFF technology. The composition of the plastisol allows to adjust the hardness and elasticity of the products obtained over a wide range, the addition of pigments and dyes allows reach different colors. The developed technology has a higher forming speed rate than the FFF technology. A possible field of application is the manufacture of seals, soundproof materials, shock and vibration absorbers, design elements of clothing and shoes. The possibility of additive manufacturing of PVC plastisol on a fabric has been experimentally confirmed. The new features of the addition manufacturing of liquid PVC plastisol and properties of products obtained by the method are investigated. Product formation takes place through the process of simultaneously converting plastisol to molten plastic compound in an extruder. The method of additive manufacturing of products from liquid plastisol is developed, which allows to obtain products with low hardness and high elasticity. The developed technology allows the formation of products from composite materials and foams with the modernization of widely available equipment.
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KARGARNEJAD, SAHAND, FARZAN GHALICHI, MOHAMMAD POURGOL-MOHAMMAD, I. Z. OSKUI und ATA GARAJEI. „BIOMECHANICAL EVALUATION OF RECONSTRUCTED EXTENSIVE MANDIBULAR DEFECTS BY DIFFERENT MODELS USING FINITE ELEMENT METHOD“. Journal of Mechanics in Medicine and Biology 20, Nr. 08 (Oktober 2020): 2050053. http://dx.doi.org/10.1142/s0219519420500530.
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Rehabilitation of major mandibular defects after tumor resection has become a serious challenge for surgeons. In this research, four various models were designed to repair a critical mandibular lateral defect. Biomechanical behavior of the models was assessed by Finite Element Method. These models are including Fibular-Free Flap (FFF), Customized Prosthesis (CP), Tray Implant without Bone Graft (TI-wo-BG), and Tray Implant with Bone Graft (TI-w-BG). FFF is a subset of microvascular free flap technique in which some segments of patient’s fibula bone are used to restore mandibular defects. CP is a hollow and light prosthesis which is fabricated using Additive Manufacturing technology from Ti alloy powder. TI-wo-BG is similar to a crib which is designed according to the geometry of the patient’s mandible. TI-w-BG, in fact, is a TI-wo-BG which is filled with small cortico-cancellous chips in order to benefit potential profit of bone grafting. The chewing operation and loading on the mandible was simulated considering the three mandibular muscular forces including masseter, medial pterygoid, and temporalis. The result of FEM analysis of TI-wo-BG and TI-w-BG showed that in both models, screw number 6 endured a strain of 5684 and 2852[Formula: see text][Formula: see text]m/m which exceeded pathological and mild overload risk, respectively. This may increase the probability of screw loosening and system failure. The results proved the stability of the FFF and CP models. In addition, it can be concluded that stress and strain on the screw’s interfaces can decrease by improving the plate and increasing the friction at the interface of plate, bone and screw.
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Przekop, Robert E., Maciej Kujawa, Wojciech Pawlak, Marta Dobrosielska, Bogna Sztorch und Wojciech Wieleba. „Graphite Modified Polylactide (PLA) for 3D Printed (FDM/FFF) Sliding Elements“. Polymers 12, Nr. 6 (29.05.2020): 1250. http://dx.doi.org/10.3390/polym12061250.
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With the development of 3D printing technology, there is a need to produce printable materials with improved properties, e.g., sliding properties. In this paper, the authors present the possibilities of producing composites based on biodegradable PLA with the addition of graphite. The team created composites with the following graphite weight contents: 1%, 2.5%, 5%, 7.5%, and 10%. Neat material was also subjected to testing. Tribological, mechanical, and chemical properties of the mentioned materials were examined. Measurements were also made after keeping the samples in ageing and climatic ovens. Furthermore, SEM observations of samples before and after friction tests were carried out. It was demonstrated that increasing graphite content caused a significant decrease in wear (PLA + 10% graphite had a wear rate three times lower than for a neat material). The addition of graphite did not adversely affect most of the other properties, but it ought to be noted that mechanical properties changed significantly. After conditioning in a climatic oven PLA + 10% graphite has (in comparison with neat material) 11% lower fracture stress, 47% lower impact strength, and 21% higher Young’s modulus. It can be certainly stated that the addition of graphite to PLA is a step towards obtaining a material that is low-cost and suitable for printing sliding spare parts.
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Podesta, Mark, Sebastiaan M. J. J. G. Nijsten, Lucas C. G. G. Persoon, Stefan G. Scheib, Christof Baltes und Frank Verhaegen. „Time dependent pre-treatment EPID dosimetry for standard and FFF VMAT“. Physics in Medicine and Biology 59, Nr. 16 (04.08.2014): 4749–68. http://dx.doi.org/10.1088/0031-9155/59/16/4749.
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Zhang, Haiguang, Di Liu, Tinglong Huang, Qingxi Hu und Herfried Lammer. „Three-Dimensional Printing of Continuous Flax Fiber-Reinforced Thermoplastic Composites by Five-Axis Machine“. Materials 13, Nr. 7 (03.04.2020): 1678. http://dx.doi.org/10.3390/ma13071678.
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A method for printing continuous flax fiber-reinforced plastic (CFFRP) composite parts by five-axis three-dimensional (3D) printer, based on fused filament fabrication (FFF) technology, has been developed. FFF printed parts usually need supporting structures, have a stair step effect, and unfavorable mechanical properties. In order to address these deficiencies, continuous natural fiber prepreg filaments were first manufactured, followed by curved path planning for the model for generation of the G-code, and finally printed by a five-axis 3D printer. The surface quality of printed parts was greatly improved. The tensile strength and modulus of CFFRP increased by 89% and 73%, respectively, compared with polylactic acid (PLA) filaments. The flexural strength and modulus of the 3D-printed CFFRP specimens increased by 211% and 224%, respectively, compared with PLA specimens. The maximal curved bending force load and stiffness of the 3D-printed CFFRP specimens increased by 39% and 115%, respectively, compared with the flat slicing method. Advanced light structures, such as leaf springs, can be designed and manufactured by taking advantage of the favorable properties of these composites, which endow them with significant potential for application in the field of automobiles.