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1
Jiang, Xin, and Ryo Koike. "Numerical Study of the Effect of High Gravity in Material Extrusion System and Polymer Characteristics during Filament Fabrication." Polymers 15, no. 14 (2023): 3037. http://dx.doi.org/10.3390/polym15143037.
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Polymer science plays a crucial role in the understanding and numerical study of material extrusion processes that have revolutionized additive manufacturing (AM). This study investigated the impact of high-gravity conditions on material extrusion and conducted a numerical study by referring to the development of a high-gravity material extrusion system (HG-MEX). In this study, we evaluated the polymeric characteristics of HG-MEX. By analyzing the interplay between polymer behavior and gravity, we provide insights into the effects of high gravity on extrusion processes, including filament flow, material deposition, and the resulting fabrication characteristics. The established numerical study of high-gravity material extrusion in additive manufacturing is a meaningful and valuable approach for improving the quality and efficiency of the process. This study is unique in that it incorporates material surface characteristics to represent the performance and contact with polymer science in additive manufacturing. The findings presented herein contribute to a broader understanding of polymer science and its practical implications for HG-MEX under various gravitational conditions.
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Alzyod, Hussein, Peter Ficzere, and Lajos Borbas. "Cost-efficient additive manufacturing: Unraveling the economic dynamics of material Extrusion (MEX) technology." International Review, no. 3-4 (2024): 185–96. https://doi.org/10.5937/intrev2404185a.
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Material Extrusion (MEX), a prevalent form of additive manufacturing (AM), plays a pivotal role in creating three-dimensional objects layer by layer. Investigating MEX printing parameters is crucial, impacting mechanical properties, roughness, material usage, build time, and dimensional accuracy. This study focuses on the economic dimensions of MEX, essential for widespread technology adoption. Understanding of the economic aspects of MEX is essential for maximizing the benefits of this additive manufacturing technology. It allows for the development of efficient, cost-effective, and sustainable manufacturing practices, contributing to its widespread adoption across diverse industries. Employing the Box-Behnken Design (BBD), the research systematically evaluates total costs, amalgamating material and power costs, providing nuanced insights into MEX economic dynamics. Analysis of variance (ANOVA) uncovers the significant impact of printing parameters, with build orientation emerging as pivotal. The optimization process aligns efficiency with cost-effectiveness, validated through robust regression equations. This study, directly relevant to management and business economics, positions itself at the forefront of advancing additive manufacturing, offering practical guidance for economic and operational optimization, particularly in industries adopting MEX technology.
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Bustos Seibert, Maximilian, Gerardo Andres Mazzei Capote, Maximilian Gruber, Wolfram Volk, and Tim A. Osswald. "Manufacturing of a PET Filament from Recycled Material for Material Extrusion (MEX)." Recycling 7, no. 5 (2022): 69. http://dx.doi.org/10.3390/recycling7050069.
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Due to its low cost and easy use, the use of material extrusion (MEX) as an additive manufacturing (AM) technology has increased rapidly in recent years. However, this process mainly involves the processing of new plastics. Combining the MEX process with polyethylene terephthalate (PET), which offers a high potential for mechanical and chemical recyclability, opens up a broad spectrum of reutilization possibilities. Turning used PET bottles into printable filament for MEX is not only a recycling option, but also an attractive upcycling scenario that can lead to the production of complex, functional parts. This work analyzes the process of extruding recycled PET bottle flakes into a filament, taking different extrusion screws and extrusion parameters into account. The filament is subsequently processed with MEX into tensile tests. An accompanying thermal, rheological and mechanical characterization of the recycled resin is performed to offer a comparison to the virgin material and a commercially available glycol modified polyethylene terephthalate (PETG) filament. The results show the importance of adequate drying parameters prior to the extrusion and the sensitivity of the material to moisture, leading to degradation. The recycled material is more prone to degradation and presents lower viscosities. Mechanical tests display a higher tensile strength of the recycled and virgin resin in comparison to the PETG. The extrusion of the used PET into a filament and the subsequent printing with the MEX process offers a viable recycling process for the discarded material.
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Sakib-Uz-Zaman, Chowdhury, and Mohammad Abu Hasan Khondoker. "A Review on Extrusion Additive Manufacturing of Pure Copper." Metals 13, no. 5 (2023): 859. http://dx.doi.org/10.3390/met13050859.
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Copper, due to its high thermal and electrical conductivity, is used extensively in many industries such as electronics, aerospace, etc. In the literature, researchers have utilized different additive manufacturing (AM) techniques to fabricate parts with pure copper; however, each technique comes with unique pros and cons. Among others, material extrusion (MEX) is a noteworthy AM technique that offers huge potential to modify the system to be able to print copper parts without a size restriction. For that purpose, copper is mixed with a binder system, which is heated in a melt chamber and then extruded out of a nozzle to deposit the material on a bed. The printed part, known as the green part, then goes through the de-binding and sintering processes to remove all the binding materials and densify the metal parts, respectively. The properties of the final sintered part depend on the processing and post-processing parameters. In this work, nine published articles are identified that focus on the 3D printing of pure copper parts using the MEX AM technique. Depending on the type of feedstock and the feeding mechanism, the MEX AM techniques for pure copper can be broadly categorized into three types: pellet-fed screw-based printing, filament-fed printing, and direct-ink write-based printing. The basic principles of these printing methods, corresponding process parameters, and the required materials and feedstock are discussed in this paper. Later, the physical, electrical, and mechanical properties of the final parts printed from these methods are discussed. Finally, some prospects and challenges related to the shrinkage of the printed copper part during post-processing are also outlined.
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Cerejo, Fábio, Daniel Gatões, and M. T. Vieira. "Optimization of metallic powder filaments for additive manufacturing extrusion (MEX)." International Journal of Advanced Manufacturing Technology 115, no. 7-8 (2021): 2449–64. http://dx.doi.org/10.1007/s00170-021-07043-0.
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AbstractAdditive manufacturing (AM) of metallic powder particles has been establishing itself as sustainable, whatever the technology selected. Material extrusion (MEX) integrates the ongoing effort to improve AM sustainability, in which low-cost equipment is associated with a decrease of powder waste during manufacturing. MEX has been gaining increasing interest for building 3D functional/structural metallic parts because it incorporates the consolidated knowledge from powder injection moulding/extrusion feedstocks into the AM scope—filament extrusion layer-by-layer. Moreover, MEX as an indirect process can overcome some of the technical limitations of direct AM processes (laser/electron-beam-based) regarding energy-matter interactions. The present study reveals an optimal methodology to produce MEX filament feedstocks (metallic powder, binder, and additives), having in mind to attain the highest metallic powder content. Nevertheless, the main challenges are also to achieve high extrudability and a suitable ratio between stiffness and flexibility. The metallic powder volume content (vol.%) in the feedstocks was evaluated by the critical powder volume concentration (CPVC). Subsequently, the rheology of the feedstocks was established by means of the mixing torque value, which is related to the filament extrudability performance.
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Michalec, Paweł, Martin Schusser, Robert Weidner, and Mathias Brandstötter. "Designing Hand Orthoses: Advances and Challenges in Material Extrusion." Applied Sciences 14, no. 20 (2024): 9543. http://dx.doi.org/10.3390/app14209543.
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The intricate structure of human hands requires personalized orthotic treatments, especially with the growing aging population’s demand for accessible care. While traditional orthoses are effective, they face challenges of cost, customization time, and accessibility. Additive manufacturing, particularly material extrusion (MEX) techniques, can effectively address challenges in orthotic device production by enabling automated, complex, and cost-effective solutions. This work aims to provide engineers with a comprehensive set of design considerations for developing hand orthoses using MEX technology, focusing on applying design for additive manufacturing principles, to enhance rehabilitation outcomes. This objective is achieved by establishing design requirements for hand orthoses, reviewing design choices and methodologies across conventional and state-of-the-art MEX-based devices, and proposing an innovative approach to orthotic design. Hand orthosis design requirements were gathered through workshops with occupational therapists and categorized into engineer-, medical-, and patient-specific needs. A review of 3D-printed hand orthoses using MEX analyzes various design approaches, providing insights into existing solutions. The study introduces a modular design concept aimed at improving rehabilitation by enhancing customizability and functionality. It highlights the potential of MEX for creating personalized, cost-effective orthoses and offers recommendations for future research, to optimize designs and improve patient outcomes.
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Budzik, Grzegorz, Mateusz Przytuła, Andrzej Paszkiewicz, Mariusz Cygnar, Łukasz Przeszłowski, and Tomasz Dziubek. "Possibilities of Automating the Additive Manufacturing Process of Material Extrusion – MEX." Tehnički glasnik 18, no. 3 (2024): 480–85. http://dx.doi.org/10.31803/tg-20240430191724.
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The article presents the possibilities of automating production pre-processing and post-processing operations for the Material Extrusion - MEX process based on Fused Filament Fabrication technology. Automation is based on hardware and software solutions. For this purpose, a special research station was developed, equipped with a warehouse of working platforms, a 3D printer and a collaborative robot that integrates individual elements of the manufacturing process. The developed solution allows for increasing the efficiency of the manufacturing cell and reducing the operator's involvement in manual operations at the pre-processing and post-processing stages.
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Nowka, Maximilian, Karl Hilbig, Lukas Schulze, Timo Heller, Marijn Goutier, and Thomas Vietor. "Influence of Manufacturing Process on the Conductivity of Material Extrusion Components: A Comparison between Filament- and Granule-Based Processes." Polymers 16, no. 8 (2024): 1134. http://dx.doi.org/10.3390/polym16081134.
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The additive manufacturing of components using material extrusion (MEX) enables the integration of several materials into one component, including functional structures such as electrically conductive structures. This study investigated the influence of the selected additive MEX process on the resistivity of MEX structures. Specimens were produced from filaments and granules of an electrically conductive PLA and filled with carbon nanotubes and carbon black. Specimens were produced with a full-factorial variation of the input variables: extrusion temperature, deposition speed, and production process. The resistivity of the specimens was determined by four-wire measurement. Analysis of the obtained data showed that only the extrusion temperature had a significant influence on the resistivity of the MEX specimens. Furthermore, the impact of the nozzle diameter was evaluated by comparing the results of this study with those of a previous study, with an otherwise equal experimental setup. The nozzle diameter had a significant influence on resistivity and a larger nozzle diameter reduced the mean variance by an order of magnitude. The resistivity was lower for most process parameter sets. As the manufacturing process had no significant influence on the resistivity of MEX structures, it can be selected based on other criteria, e.g., the cost of feedstock.
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Vidakis, Nectarios, Markos Petousis, Panagiotis Mangelis, et al. "Thermomechanical Response of Polycarbonate/Aluminum Nitride Nanocomposites in Material Extrusion Additive Manufacturing." Materials 15, no. 24 (2022): 8806. http://dx.doi.org/10.3390/ma15248806.
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Polycarbonate-based nanocomposites were developed herein through a material extrusion (MEX) additive manufacturing (AM) process. The fabrication of the final nanocomposite specimens was achieved by implementing the fused filament fabrication (FFF) 3D printing process. The impact of aluminum nitride (AlN) nanoparticles on the thermal and mechanical behavior of the polycarbonate (PC) matrix was investigated thoroughly for the fabricated nanocomposites, carrying out a range of thermomechanical tests. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) provided information about the morphological and surface characteristics of the produced specimens. Using energy dispersive spectroscopy (EDS), the elemental composition of the nanocomposite materials was validated. Raman spectroscopy revealed no chemical interactions between the two material phases. The results showed the reinforcement of most mechanical properties with the addition of the AlN nanoparticles. The nanocomposite with 2 wt.% filler concentration exhibited the best mechanical performance overall, with the highest improvements observed for the tensile strength and toughness of the fabricated specimens, with a percentage of 32.8% and 51.6%, respectively, compared with the pure polymer. The successful AM of PC/AlN nanocomposites with the MEX process is a new paradigm, which expands 3D printing technology and opens a new route for the development of nanocomposite materials with multifunctional properties for industrial applications.
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Cherouat, Abel, Thierry Barriere, and Hong Wang. "Optimization of extrudate swell during extrusion-based additive manufacturing process." E3S Web of Conferences 631 (2025): 01007. https://doi.org/10.1051/e3sconf/202563101007.
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Die swell is the expansion of the extrudate diameter upon exiting the die, resulting from the polymer melt or ink undergoes high shear stress due to the pressure-driven flow, viscoelastic relaxation phenomenon and the molecular chains stretching and oriented in the flow direction. Die swell affects dimensional accuracy and interlayer bonding and it's crucial to understood and controlled for high-precision manufacturing. It can be affected by multiple factors including material properties and processing parameters that can be coupled and it is difficult to fully understand their effects. To minimize or control extrudate swell it is necessary to identify the optimal combination of process parameters using Orthogonal Arrays. In this study, Orthogonal Experimental Design is used to optimize extrudate swell during extrusion-based additive manufacturing MEX of biodegradable polylactic acid material. It allows to systematically investigate the influence of multiple process parameters and their interactions on the swell ratio, using a minimal number of experiments. Simulating swell during extrusion with COMSOL Multiphysics requires combining computational fluid dynamics and Level Set method with rheological modeling of the extruded material. The results and analyses of the numerical simulation were used to predict and optimize the extrudate swelling in the MEX process.
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Asami, Karim, Maxim Kuehne, Tim Röver, and Claus Emmelmann. "Application of Machine Learning in Predicting Quality Parameters in Metal Material Extrusion (MEX/M)." Metals 15, no. 5 (2025): 505. https://doi.org/10.3390/met15050505.
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Additive manufacturing processes such as the material extrusion of metals (MEX/M) enable the production of complex and functional parts that are not feasible to create through traditional manufacturing methods. However, achieving high‑quality MEX/M parts requires significant experimental and financial investments for suitable parameter development. In response, this study explores the application of machine learning (ML) to predict the surface roughness and density in MEX/M components. The various models are trained with experimental data using input parameters such as layer thickness, print velocity, infill, overhang angle, and sinter profile enabling precise predictions of surface roughness and density. The various ML models demonstrate an accuracy of up to 97% after training. In conclusion, this research showcases the potential of ML in enhancing the efficiency in control over component quality during the design phase, addressing challenges in metallic additive manufacturing, and facilitating exact control and optimization of the MEX/M process, especially for complex geometrical structures.
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Sadaf, Mahrukh, Mario Bragaglia, Lidija Slemenik Perše, and Francesca Nanni. "Advancements in Metal Additive Manufacturing: A Comprehensive Review of Material Extrusion with Highly Filled Polymers." Journal of Manufacturing and Materials Processing 8, no. 1 (2024): 14. http://dx.doi.org/10.3390/jmmp8010014.
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Additive manufacturing (AM) has attracted huge attention for manufacturing metals, ceramics, highly filled composites, or virgin polymers. Of all the AM methods, material extrusion (MEX) stands out as one of the most widely employed AM methods on a global scale, specifically when dealing with thermoplastic polymers and composites, as this technique requires a very low initial investment and usage simplicity. This review extensively addresses the latest advancements in the field of MEX of feedstock made of polymers highly filled with metal particles. After developing a 3D model, the polymeric binder is removed from the 3D-printed component in a process called debinding. Furthermore, sintering is conducted at a temperature below the melting temperature of the metallic powder to obtain the fully densified solid component. The stages of MEX-based processing, which comprise the choice of powder, development of binder system, compounding, 3D printing, and post-treatment, i.e., debinding and sintering, are discussed. It is shown that both 3D printing and post-processing parameters are interconnected and interdependent factors, concurring in determining the resulting mechanical properties of the sintered metal. In particular, the polymeric binder, along with its removal, results to be one of the most critical factors in the success of the entire process. The mechanical properties of sintered components produced through MEX are generally inferior, compared with traditional techniques, as final MEX products are more porous.
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Ulmeanu, Mihaela-Elena, Cristian-Vasile Doicin, Liviu Roşca, Allan Ew Rennie, Tom Abram, and Andrei-Bogdan Nuţă. "Study regarding the influence of material type on economic objectives in MEX fabrication." MATEC Web of Conferences 343 (2021): 02009. http://dx.doi.org/10.1051/matecconf/202134302009.
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Material Extrusion has been used extensively as an additive manufacturing technology for a variety of applications like visual models, functional prototypes, tooling components, patterns for castings, and final parts. The current research paper proposes a study on the material type influence on economic objectives in material extrusion fabrication of complex assemblies. Three economic objectives have been analysed, namely, estimated fabrication time, material usage and material cost, whilst two commercial additive manufacturing machines have been considered for the simulation. Cura and ZSuite slicing software were used for the generation of Gcode and project files. Five filaments were selected from the same manufacturer and all components of the selected assembly were included in the analysis. Throughout the study, the additive manufacturing parameters were kept constant, as well as the component layout on the build platform of the two machines. Study results were analysed in correspondence with the manufacturing requirements and the optimum fabrication scenario was selected. Further research includes the analysis of multiple material manufacturers, in order to evaluate the influence of chemical composition on economic outputs.
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Pang, Rayson, Mun Kou Lai, Hiu Hong Teo, and Tze Chuen Yap. "Influence of Temperature on Interlayer Adhesion and Structural Integrity in Material Extrusion: A Comprehensive Review." Journal of Manufacturing and Materials Processing 9, no. 6 (2025): 196. https://doi.org/10.3390/jmmp9060196.
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Additive manufacturing technologies are being increasingly adopted in the manufacturing industries due to their capabilities in producing complex geometries without the need for special tools. Material extrusion (MEX-TRB/P) is a popular additive manufacturing technology due to its simple operation. However, optimization of various process parameters remains a challenge, as incorrect combinations can lead to reduced dimensional accuracy and incapacitated mechanical properties of the fabricated parts. Given that the MEX-TRB/P process relies on the heating and cooling of thermoplastic materials, understanding the role of temperature is critical to optimizing the MEX-TRB/P printed parts. This article reviews existing research on the effects of process parameters, specifically those that are temperature sensitive, on the mechanical properties of the printed parts. The review first classified the process parameters into temperature sensitive and non-temperature sensitive process parameters. Then, the influence of temperature on the bonding quality and material properties is investigated, and a relationship between the thermal conditions and mechanical properties of 3D printed parts is established. This review also summarizes experimental and numerical methods for investigating temperature evolution during printing. This study aims to provide a deep understanding of the optimization of temperature-sensitive process parameters and their role in enhancing the mechanical properties of MEX-TRB/P-printed parts.
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Nowka, Maximilian, Karl Hilbig, Lukas Schulze, Eggert Jung, and Thomas Vietor. "Influence of Process Parameters in Material Extrusion on Product Properties Using the Example of the Electrical Resistivity of Conductive Polymer Composites." Polymers 15, no. 22 (2023): 4452. http://dx.doi.org/10.3390/polym15224452.
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Additive manufacturing of components using the material extrusion (MEX) of thermoplastics enables the integration of multiple materials into a single part. This can include functional structures, such as electrically conductive ones. The resulting functional structure properties depend on the process parameters along the entire manufacturing chain. The aim of this investigation is to determine the influence of process parameters in filament production and additive manufacturing on resistivity. Filament is produced from a commercially available composite of polylactide (PLA) with carbon nanotubes (CNT) and carbon black (CB), while the temperature profile and screw speed were varied. MEX specimens were produced using a full-factorial variation in extrusion temperature, layer height and deposition speed from the most and least conductive in-house-produced filament and the commercially available filament from the same composite. The results show that the temperature profile during filament production influences the resistivity. The commercially available filament has a lower conductivity than the in-house-produced filament, even though the starting feedstock is the same. The process parameters during filament production are the main factors influencing the resistivity of an additively manufactured structure. The MEX process parameters have a minimal influence on the resistivity of the used PLA/CNT/CB composite.
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Asami, Karim, Mehar Prakash Reddy Medapati, Titus Rakow, Tim Röver, and Claus Emmelmann. "Design Guidelines for Material Extrusion of Metals (MEX/M)." Journal of Experimental and Theoretical Analyses 3, no. 2 (2025): 15. https://doi.org/10.3390/jeta3020015.
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This study introduced a systematic framework to develop practical design guidelines specifically for filament-based material extrusion of metals (MEX/M), an additive manufacturing (AM) process defined by ISO/ASTM 52900. MEX/M provides a cost-efficient alternative to conventional manufacturing methods, which is particularly valuable for rapid prototyping. Although AM offers significant design flexibility, the MEX/M process imposes distinct geometric and process constraints requiring targeted optimization. The research formulates and validates design guidelines tailored for the MEX/M using an austenitic steel 316L (1.4404) alloy filament. The feedstock consists of a uniform blend of 316L stainless steel powder and polymeric binder embedded within a thermoplastic matrix, extruded and deposited layer by layer. Benchmark parts were fabricated to examine geometric feasibility, such as minimum printable wall thickness, feature inclination angles, borehole precision, overhang stability, and achievable resolution of horizontal and vertical gaps. After fabrication, the as-built (green-state) components undergo a two-step thermal post-processing treatment involving binder removal (debinding), followed by sintering at elevated temperatures to reach densification. Geometric accuracy was quantitatively assessed through a 3D scan by comparing the manufactured parts to their original CAD models, allowing the identification of deformation patterns and shrinkage rates. Finally, the practical utility of the developed guidelines was demonstrated by successfully manufacturing an impeller designed according to the established geometric constraints. These design guidelines apply specifically to the machine and filament type utilized in this study.
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Jasik, Katarzyna, Lucjan Śnieżek, and Janusz Kluczyński. "Additive Manufacturing of Metals Using the MEX Method: Process Characteristics and Performance Properties—A Review." Materials 18, no. 12 (2025): 2744. https://doi.org/10.3390/ma18122744.
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Compared to traditional manufacturing methods, additive manufacturing (AM) enables the production of parts with arbitrary structures, effectively addressing the challenges faced when fabricating complex geometries using conventional techniques. The dynamic development of this technology has led to the emergence of increasingly advanced materials. One of the best examples is metal–polymer composites, which allow the manufacturing of fully dense components consisting of stainless steel and titanium alloys, employing the widely available AM technology based on material extrusion (MEX). Metallic materials intended for this type of 3D printing may serve as an alternative to currently prevalent techniques including techniques like selective laser melting (SLM), owing to significantly lower equipment and material costs. Particularly applicable in low-volume production, where total costs and manufacturing time are critical factors, MEX technology of polymer–metallic composites offer relatively fast and economical AM of metal components, proving beneficial during the design of geometrically complex, and low-cost equipment. Due to the significant advancements in AM technology, this review focuses on the latest developments in the additive manufacturing of metallic components using the MEX approach. The discussion encompasses the printing process characteristics, materials tailored to this technology, and post-processing steps (debinding and sintering) necessary for obtaining fully metallic MEX components. Additionally, the article characterizes the printing process parameters and their influence on the functional characteristics of the resulting components. Finally, it presents the drawbacks of the process, identifies gaps in existing research, and outlines challenges in refining the technology.
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Suwanpreecha, Chanun, and Anchalee Manonukul. "A Review on Material Extrusion Additive Manufacturing of Metal and How It Compares with Metal Injection Moulding." Metals 12, no. 3 (2022): 429. http://dx.doi.org/10.3390/met12030429.
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Material extrusion additive manufacturing of metal (metal MEX), which is one of the 3D printing processes, has gained more interests because of its simplicity and economics. Metal MEX process is similar to the conventional metal injection moulding (MIM) process, consisting of feedstock preparation of metal powder and polymer binders, layer-by-layer 3D printing (metal MEX) or injection (MIM) to create green parts, debinding to remove the binders and sintering to create the consolidated metallic parts. Due to the recent rapid development of metal MEX, it is important to review current research work on this topic to further understand the critical process parameters and the related physical and mechanical properties of metal MEX parts relevant to further studies and real applications. In this review, the available literature is systematically summarised and concluded in terms of feedstock, printing, debinding and sintering. The processing-related physical and mechanical properties, i.e., solid loading vs. dimensional shrinkage maps, sintering temperature vs. relative sintered density maps, stress vs. elongation maps for the three main alloys (316L stainless steel, 17-4PH stainless steel and Ti-6Al-4V), are also discussed and compared with well-established MIM properties and MIM international standards to assess the current stage of metal MEX development.
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Forstner, Thomas, Simon Cholewa, and Dietmar Drummer. "Enhanced Feedstock Processability for the Indirect Additive Manufacturing of Metals by Material Extrusion through Ethylene–Propylene Copolymer Modification." Polymers 16, no. 18 (2024): 2658. http://dx.doi.org/10.3390/polym16182658.
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Filament-based material extrusion (MEX) represents one of the most commonly used additive manufacturing techniques for polymer materials. In a special variation of this process, highly filled polymer filaments are used to create metal parts via a multi-step process. The challenges associated with creating a dense final part are versatile due to the different and partly contrary requirements of the individual processing steps. Especially for processing in MEX, the compound must show sufficiently low viscosity, which is often achieved by the addition of wax. However, wax addition also leads to a significant reduction in ductility. This can cause filaments to break, which leads to failure of the MEX process. Therefore, the present study investigates the influence of different ethylene–propylene copolymers (EPCs) with varying ethylene contents as a ductility-enhancing component within the feedstock to improve filament processing behavior. The resulting feedstock materials are evaluated regarding their mechanical, thermal and debinding behavior. In addition, the processability in MEX is assessed. This study shows that a rising ethylene content within the EPC leads to a higher ductility and an enhanced filament flexibility while also influencing the crystallization behavior of the feedstock. For the MEX process, an ethylene fraction of 12% within the EPC was found to be the optimum regarding processability for the highly filled filaments in MEX and the additional processing steps to create sintered metal parts.
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Bernagozzi, Giulia, Daniele Battegazzore, Rossella Arrigo, and Alberto Frache. "Optimizing the Rheological and Thermal Behavior of Polypropylene-Based Composites for Material Extrusion Additive Manufacturing Processes." Polymers 15, no. 10 (2023): 2263. http://dx.doi.org/10.3390/polym15102263.
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In this study, composites based on a heterophasic polypropylene (PP) copolymer containing different loadings of micro-sized (i.e., talc, calcium carbonate, and silica) and nano-sized (i.e., a nanoclay) fillers were formulated via melt compounding to obtain PP-based materials suitable for Material Extrusion (MEX) additive manufacturing processing. The assessment of the thermal properties and the rheological behavior of the produced materials allowed us to disclose the relationships between the influence of the embedded fillers and the fundamental characteristics of the materials affecting their MEX processability. In particular, composites containing 30 wt% of talc or calcium carbonate and 3 wt% of nanoclay showed the best combination of thermal and rheological properties and were selected for 3D printing processing. The evaluation of the morphology of the filaments and the 3D-printed samples demonstrated that the introduction of different fillers affects their surface quality as well as the adhesion between subsequently deposited layers. Finally, the tensile properties of 3D-printed specimens were assessed; the obtained results showed that modulable mechanical properties can be achieved depending on the type of the embedded filler, opening new perspectives towards the full exploitation of MEX processing in the production of printed parts endowed with desirable characteristics and functionalities.
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Nowka, Maximilian, Katja Ruge, Lukas Schulze, Karl Hilbig, and Thomas Vietor. "Characterization of the Anisotropic Electrical Properties of Additively Manufactured Structures Made from Electrically Conductive Composites by Material Extrusion." Polymers 16, no. 20 (2024): 2891. http://dx.doi.org/10.3390/polym16202891.
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Additive manufacturing (AM) of components using material extrusion (MEX) offers the potential for the integration of functions through the use of multi-material design, such as sensors, actuators, energy storage, and electrical connections. However, there is a significant gap in the availability of electrical composite properties, which is essential for informed design of electrical functional structures in the product development process. This study addresses this gap by systematically evaluating the resistivity (DC, direct current) of 14 commercially available filaments as unprocessed filament feedstock, extruded fibers, and fabricated MEX-structures. The analysis of the MEX-structures considers the influence of anisotropic electrical properties induced by the selective material deposition inherent to MEX. The results demonstrate that composites containing fillers with a high aspect ratio, such as carbon nanotubes (CNT) and graphene, significantly enhance conductivity and improve the reproducibility of MEX structures. Notably, the extrusion of filaments into MEX structures generally leads to an increase in resistivity; however, composites with CNT or graphene exhibit less reduction in conductivity and lower variability compared to those containing only carbon black (CB) or graphite. These findings underscore the importance of filler selection and composition in optimizing the electrical performance of MEX structures.
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Fernández, Alejandro, Pablo Zapico, David Blanco, Fernando Peña, Natalia Beltrán, and Sabino Mateos. "On-Machine LTS Integration for Layer-Wise Surface Quality Characterization in MEX/P." Sensors 24, no. 11 (2024): 3459. http://dx.doi.org/10.3390/s24113459.
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Material Extrusion (MEX) currently stands as the most widespread Additive Manufacturing (AM) process, but part quality deficiencies remain a barrier to its generalized industrial adoption. Quality control in MEX is a complex task as extrusion performance impacts the consistency of mechanical properties and the surface finish, dimensional accuracy, and geometric precision of manufactured parts. Recognizing the need for early-stage process monitoring, this study explores the potential of integrating Laser Triangulation Sensors (LTS) into MEX/P manufacturing equipment for layer-wise 3D inspections. Using a double-bridge architecture, an LTS-based sub-micrometric inspection system operates independently from the manufacturing process, enabling comprehensive digitization and autonomous reconstruction of the target layer’s topography. Surface texture is then computed using standardized indicators and a new approach that provides insight into layer quality uniformity. A case study evaluating two alternative extruder head designs demonstrates the efficacy of this integrated approach for layer quality characterization. Implementing a generalized layer-wise procedure based on this integration can significantly mitigate quality issues in MEX manufacturing and optimize process parameter configurations for enhanced performance.
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Locatelli, Gabriele, Mariangela Quarto, Gianluca D’Urso, and Claudio Giardini. "Geometric Benchmarking of Metal Material Extrusion Technology: A Preliminary Study." Applied Sciences 14, no. 14 (2024): 6229. http://dx.doi.org/10.3390/app14146229.
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Metal additive manufacturing technologies such as powder bed fusion (PBF) and direct energy deposition (DED) are experiencing fast development, due to the growing awareness of industries. However, high energy consumption, slow production processes, and high costs of both machines and feedstocks hamper their competitiveness, compared to conventional manufacturing techniques. Metal material extrusion (metal-MEX) can represent a cost- and energy-effective alternative for metal additive manufacturing. This article aims to assess the potential of such technology by addressing uncertainties related to product design and process stability through a preliminary geometric benchmarking study. The geometric tolerances and minimum achievable sizes of some simple geometries produced in 316L stainless steel were evaluated using geometric benchmark test artifacts (GBTAs). Process maps were also proposed to forecast the feasibility of achieving acceptable values of the investigated tolerances, based on the nominal dimensions of the features.
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Ma, Dingyifei, Xiaoqing Tian, Shengyi Wang, et al. "Strand-Morphology-Based Process Optimization for Extrusion-Based Silicone Additive Manufacturing." Polymers 13, no. 20 (2021): 3576. http://dx.doi.org/10.3390/polym13203576.
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In the silicone material extrusion (MEX) process, product profile error and performance defects are common problems due to changes in strand shape. A process optimization method considering strand morphology, denoted as SMO, which allows adjustment of the strand shape by adjusting process parameters during the printing process is presented. The relation between process parameters (extrusion speed, moving speed, nozzle height, and nozzle radius) and the geometric parameters (strand width and strand height) of the cross-section, as well as the relationship between strand spacing, layer height, and process parameters in no void constraint is discussed and verified. SMO was utilized to produce specimens with tunable strand width and strand height. Tensile tests and profile scans were performed to compare SMO with other methods to verify its feasibility. Specimens fabricated using the SMO method have up to a 7% increase in tensile strength, up to a 10% reduction in processing time, and about a 60% reduction in strand height error over unused ones. The results show that the SMO method with adjustable strand width can effectively balance efficiency and mechanical properties compared to uniform infill, and the SMO method with adjustable strand height can provide higher accuracy compared to uniform strand height. The proposed method is validated and improves the efficiency and accuracy of silicone MEX.
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Jafor, Md Abu, Neshat Sayah, Douglas E. Smith, Gianni Stano, and Trevor J. Fleck. "Systematic Evaluation of Adhesion and Fracture Toughness in Multi-Material Fused Deposition Material Extrusion." Materials 17, no. 16 (2024): 3953. http://dx.doi.org/10.3390/ma17163953.
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Material extrusion (MEX) additive manufacturing has successfully fabricated assembly-free structures composed of different materials processed in the same manufacturing cycle. Materials with different mechanical properties can be employed for the fabrication of bio-inspired structures (i.e., stiff materials connected to soft materials), which are appealing for many fields, such as bio-medical and soft robotics. In the present paper, process parameters and 3D printing strategies are presented to improve the interfacial adhesion between carbon fiber-reinforced nylon (CFPA) and thermoplastic polyurethane (TPU), which are extruded in the same manufacturing cycle using a multi-material MEX setup. To achieve our goal, a double cantilever beam (DCB) test was used to evaluate the mode I fracture toughness. The results show that the application of a heating gun (assembled near the nozzle) provides a statistically significant increase in mean fracture toughness energy from 12.3 kJ/m2 to 33.4 kJ/m2. The underlying mechanism driving this finding was further investigated by quantifying porosity at the multi-material interface using an X-ray computed tomography (CT) system, in addition to quantifying thermal history. The results show that using both bead ironing and the hot air gun during the printing process leads to a reduction of 24% in the average void volume fraction. The findings from the DCB test and X-ray CT analysis agree well with the polymer healing theory, in which an increased thermal history led to an increased fracture toughness at the multi-material interface. Moreover, this study considers the thermal history of each printed layer to correlate the measured debonding energy with results obtained using the reptation theory.
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Gonzalez-Gutierrez, Joamin, Santiago Cano, Josef Valentin Ecker, et al. "Bending Properties of Lightweight Copper Specimens with Different Infill Patterns Produced by Material Extrusion Additive Manufacturing, Solvent Debinding and Sintering." Applied Sciences 11, no. 16 (2021): 7262. http://dx.doi.org/10.3390/app11167262.
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Material extrusion additive manufacturing (MEX) is a versatile technology for producing complex specimens of polymers, ceramics and metals. Highly-filled filaments composed of a binder system and a high-volume content of sinterable powders are needed to produce ceramic or metal parts. After shaping the parts via MEX, the binder is removed and the specimens are sintered to obtain a dense part of the sintered filler particles. In this article, the applicability of this additive manufacturing process to produce copper specimens is demonstrated. The particular emphasis is on investigating the production of lightweight specimens that retain mechanical properties without increasing their weight. The effect of infill grades and the cover presence on the debinding process and the flexural properties of the sintered parts was studied. It was observed that covers could provide the same flexural strength with a maximum weight reduction of approximately 23%. However, a cover on specimens with less than 100% infill significantly slows down the debinding process. The results demonstrate the applicability of MEX to produce lightweight copper specimens.
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Marchal, Valentin, Yicha Zhang, Nadia Labed, Rémy Lachat, and François Peyraut. "Fast layer fiber orientation optimization method for continuous fiber-reinforced material extrusion process." Materials Science in Additive Manufacturing 2, no. 1 (2023): 49. http://dx.doi.org/10.36922/msam.49.
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Material extrusion (MEX) is an additive manufacturing process that uses thermoplastic layer-by-layer building. The use of continuous fiber-reinforced filament enhances mechanical properties, making MEX suitable for use in aerospace, automotive, and robotics industries. This study proposes a laminate optimization method to improve the stiffness of printed parts with low computing time. The 2D stress-flow-based method optimizes fiber’s orientation for each layer in the stacking direction, giving results for a 3D part optimization in a few minutes. Developed with Ansys Parametric Design Language, the computation tool was tested on printed wrenches, resulting in an 18% increase in stiffness. The proposed method is applicable to any printable shape.
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Fernández, Alejandro, Pedro Fernández, Fernando Peña, and David Blanco. "On-Machine CIS SoC-Based Layerwise Inspection System for MEX Additive Manufacturing." Key Engineering Materials 961 (October 11, 2023): 143–50. http://dx.doi.org/10.4028/p-p0iycb.
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Additive manufacturing processes build three-dimensional objects usually following a layer-upon-layer strategy. An interesting feature of this strategy is that each layer could be inspected before the next one is deposited. On-machine integration of layerwise inspection systems would not only allow for early characterization of the dimensional and geometric quality of the part, but also for the detection of intralayer defects. Contact image sensors (CIS), such as those used in desktop flatbed scanners, could be used for this purpose since they would provide bi-dimensional digital images of the whole layer and its neighborhood. CIS images combine high resolutions with a reduced acquisition time. In this work, a material extrusion (MEX) additive manufacturing system, with layerwise inspection capabilities is proposed. The system has been equipped with the CIS that Epson uses in its Perfection V39 flatbed scanner. The sensor provides two analog output signals, each one consisting on 2584 voltage levels, that represent the amount of light reflected by the material. This analog information is sent to a parallel AD converter, where an 8-bit encoding is assigned to each one of the pixels on the digitized image. To overcome microcontroller-related problems, a Zynq®-7000 system-on-chip (SoC) has been used. This SoC integrates an ARM® based processor, with the hardware programming of a field programmable gate array (FPGA). This architecture ensures an accurate and controlled readout of the various AD converters. The resultant digital image of each layer could then be then processed using different algorithms to detect defects, extract the geometry of the layer contour and characterize the dimensional and geometric quality of the object. In the example provided, a forced error consisting on 0.2 mm height local deviations, caused by a variation in extrusion temperature, was identified from 2D grayscale images obtained with the CIS sensor.
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Hanemann, Thomas, Alexander Klein, Siegfried Baumgärtner, Judith Jung, David Wilhelm, and Steffen Antusch. "Material Extrusion 3D Printing of PEEK-Based Composites." Polymers 15, no. 16 (2023): 3412. http://dx.doi.org/10.3390/polym15163412.
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High-performance thermoplastics like polyetheretherketone (PEEK), with their outstanding thermal stability, mechanical properties and chemical stability, have great potential for various structural applications. Combining with additive manufacturing methods extends further PEEK usage, e.g., as a mold insert material in polymer melt processing like injection molding. Mold inserts must possess a certain mechanical stability, a low surface roughness as well as a good thermal conductivity for the temperature control during the molding process. With this in mind, the commercially available high-performance thermoplastic PEEK was doped with small amounts of carbon nanotubes (CNT, 6 wt%) and copper particles (10 wt%) targeting enhanced thermomechanical properties and a higher thermal conductivity. The composites were realized by a commercial combined compounder and filament maker for the usage in a material extrusion (MEX)-based 3D-printer following the fused filament fabrication (FFF) principle. Commercial filaments made from PEEK and carbon fiber reinforced PEEK were used as reference systems. The impact of the filler and the MEX printing conditions like printing temperature, printing speed and infill orientation on the PEEK properties were characterized comprehensively by tensile testing, fracture imaging and surface roughness measurements. In addition, the thermal conductivity was determined by the laser-flash method in combination with differential scanning calorimetry and Archimedes density measurement. The addition of fillers did not alter the measured tensile strength in comparison to pure PEEK significantly. The fracture images showed a good printing quality without the MEX-typical voids between and within the deposited layers. Higher printing temperatures caused a reduction of the surface roughness and, in some cases, an enhanced ductile behavior. The thermal conductivity could be increased by the addition of the CNTs. Following the given results, the most critical process step is the compounding procedure, because for a reliable process–parameter–property relationship, a homogeneous particle distribution in the polymer matrix yielding a reliable filament quality is essential.
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Vidakis, Nectarios, Markos Petousis, Nikolaos Mountakis, et al. "Glass Fillers in Three Different Forms Used as Reinforcement Agents of Polylactic Acid in Material Extrusion Additive Manufacturing." Applied Sciences 13, no. 11 (2023): 6471. http://dx.doi.org/10.3390/app13116471.
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The industrial demand for functional filaments made of bio-sourced, biocompatible, biodegradable, and/or recyclable polymers and composites for material extrusion (MEX) 3D printing is continuously growing. Polylactic acid (PLA), the most popular filament, combines such properties, yet its reinforcement with low-cost, inert, and/or recycled fillers remains challenging. Herein, glass in three different micro/nano-forms was the reinforcement agent in PLA. Three different experimental tiers were elaborated by producing composite filaments with glass in powder, beads, and flake forms in various loadings to optimize the concentrations. A thermomechanical process, i.e., melt filament extrusion, was exploited. The composites were evaluated for their thermal degradation stability and composition using thermogravimetric analysis and Raman. MEX 3D printing was used to produce tensile, flexural, impact, and microhardness specimens, to quantitatively evaluate their mechanical response. Field emission scanning electron microscopy evaluation and fractography were carried out to depict fracture patterns of the specimens after their tests. All three glass types induced impressive reinforcement effects (up to 60% in flexural loading), especially in the flake form. The impact of the additional process cost through glass fillers implementation was also assessed, indicating that such composites are cost-effective.
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Vidakis, Nectarios, Markos Petousis, Amalia Moutsopoulou, et al. "Nanocomposites with Optimized Polytetrafluoroethylene Content as a Reinforcement Agent in PA12 and PLA for Material Extrusion Additive Manufacturing." Polymers 15, no. 13 (2023): 2786. http://dx.doi.org/10.3390/polym15132786.
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Herein, polytetrafluoroethylene (PTFE) is evaluated as a reinforcement agent in material extrusion (MEX) additive manufacturing (AM), aiming to develop nanocomposites with enhanced mechanical performance. Loadings up to 4.0 wt.% were introduced as fillers of polylactic acid (PLA) and polyamide 12 (PA12) matrices. Filaments for MEX AM were prepared to produce corresponding 3D-printed samples. For the thorough characterization of the nanocomposites, a series of standardized mechanical tests were followed, along with AFM, TGA, Raman spectroscopy, EDS, and SEM analyses. The results showed an improved mechanical response for filler concentrations between 2.0 and 3.0 wt.%. The enhancement for the PLA/PTFE 2.0 wt.% in the tensile strength reached 21.1% and the modulus of elasticity 25.5%; for the PA12/PTFE 3.0 wt.%, 34.1%, and 41.7%, respectively. For PLA/PTFE 2.0 wt.%, the enhancement in the flexural strength reached 57.6% and the modulus of elasticity 25.5%; for the PA12/PTFE 3.0 wt.%, 14.7%, and 17.2%, respectively. This research enables the ability to deploy PTFE as a reinforcement agent in the PA12 and PLA thermoplastic engineering polymers in the MEX AM process, expanding the potential applications.
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Puppi, Dario, Gianni Pecorini, and Gianluca Parrini. "Additive Manufacturing of Anatomical Poly(d,l-lactide) Scaffolds." Polymers 14, no. 19 (2022): 4057. http://dx.doi.org/10.3390/polym14194057.
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Poly(lactide) (PLA) is one of the most investigated semicrystalline polymers for material extrusion (MEX) additive manufacturing (AM) techniques based on polymer melt processing. Research on its application for the development of customized devices tailored to specific anatomical parts of the human body can provide new personalized medicine strategies. This research activity was aimed at testing a new multifunctional AM system for the design and fabrication by MEX of anatomical and dog-bone-shaped PLA samples with different infill densities and deposition angles. In particular, a commercial PLA filament was employed to validate the computer-aided design (CAD) and manufacturing (CAM) process for the development of scaffold prototypes modeled on a human bone defect. Physical-chemical characterization of the obtained samples by 1H-NMR spectroscopy, size exclusion chromatography (SEC), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) demonstrated a small reduction of polymer molecular weight (~5%) due to thermal processing, as well as that the commercial polymer employed was a semicrystalline poly(d,l-lactide). Mechanical characterization highlighted the possibility of tuning elastic modulus and strength, as well as the elongation at break up to a 60% value by varying infill parameters.
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Tuazon, Brian J., and John Ryan Cortez Dizon. "Additive Manufacturing Technology in the Furniture Industry: Future Outlook for Developing Countries." Advance Sustainable Science Engineering and Technology 6, no. 3 (2024): 02403024. http://dx.doi.org/10.26877/asset.v6i3.908.
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For the past few years, the adoption of 3D printing technology has benefited various manufacturing industries, including the furniture making industry. However, this adoption has been greatly seen in industrialized countries and lacking in developing countries. Therefore, to understand fully the capability of 3D printing and its benefits, this paper review discusses recent applications of 3D printing in the furniture industry and assesses the potential it can bring for developing countries’ furniture making industry, specifically in the Philippines and other developing countries in Asia. In addition, the drawbacks it brought to the industry, and the challenges that needed to be addressed are also discussed in the paper. The paper covers various 3D printing technologies such as material extrusion, sheet lamination, powder bed fusion, and vat photopolymerization, along with different materials currently used in the furniture industry. Numerous notable examples of applications of 3D-printed furniture are also presented. Based on the review paper, it was found that the most common 3D printing technologies used in the furniture industry are Material Extrusion (MEX) and Powder Bed Fusion (PBF) specifically Fused Deposition Modelling (FDM) and Selective Laser Sintering (SLS), respectively. The most common 3D printing materials used are Polyamide (PA), Polylactic acid (PLA), and recycled Polyethylene terephthalate glycol (PETG). The paper also discusses the possible adoption of 3D printing in developing countries and explores its potential to innovate traditional furniture manufacturing processes.
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Siedlecki, Krzysztof, Marcin Słoma, and Andrzej Skalski. "Comparison between Micro-Powder Injection Molding and Material Extrusion Additive Manufacturing of Metal Powders for the Fabrication of Sintered Components." Materials 16, no. 23 (2023): 7268. http://dx.doi.org/10.3390/ma16237268.
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Original compositions based on iron micro-powders and an organic binder mixture were developed for the fabrication of sintered metallic elements with micro-powder injection molding (µPIM) and material extrusion additive manufacturing of metal powders (MEX). The binder formulation was thoroughly adjusted to exhibit rheological and thermal properties suitable for µPIM and MEX. The focus was set on adapting the proper binder composition to meet the requirements for injection/extrusion and, at the same time, to have comparable thermogravimetric characteristics for the thermal debinding and sintering process. A basic analysis of the forming process indicates that the pressure has a low influence on clogging, while the temperature of the material and mold/nozzle impacts the viscosity of the composition significantly. The influence of the Fe micro-powder content in the range of 45–60 vol.% was evaluated against the injection/extrusion process parameters and properties of sintered elements. Different debinding and sintering processes (chemical and thermal) were evaluated for the optimal properties of the final samples. The obtained sintered elements were of high quality and showed minor signs of binder-related flaws, with shrinkage in the range of 10–15% for both the injection-molded and 3D printed parts. These results suggest that, with minor modifications, compositions tailored for the PIM technique can be adapted for the additive manufacturing of metal parts, achieving comparable characteristics of the parts obtained for both forming methods.
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Vidakis, Nectarios, Markos Petousis, Sotirios Grammatikos, Vassilis Papadakis, Apostolos Korlos, and Nikolaos Mountakis. "High Performance Polycarbonate Nanocomposites Mechanically Boosted with Titanium Carbide in Material Extrusion Additive Manufacturing." Nanomaterials 12, no. 7 (2022): 1068. http://dx.doi.org/10.3390/nano12071068.
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Herein, a polycarbonate (PC) polymer is melt extruded together with titanium carbide (TiC) nano powder for the development of advanced nanocomposite materials in material extrusion (MEX) 3D printing. Raw material for the 3D printing process was prepared in filament form with a thermomechanical extrusion process and specimens were built to be tested according to international standards. A thorough mechanical characterization testing course (tensile, flexural, impact, microhardness, and dynamic mechanical analysis-DMA) was conducted on the 3D printed specimens. The effect of the ceramic filler loading was also investigated. The nanocomposites’ thermal and stoichiometric properties were investigated with thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), energy-dispersive X-ray spectroscopy (EDS), and Raman respectively. The specimens’ 3D printing morphology, quality, and fracture mechanism were investigated with atomic force microscopy (AFM) and scanning electron microscopy (SEM) respectively. The results depicted that the addition of the filler decidedly enhances the mechanical response of the virgin polymer, without compromising properties such as its processability or its thermal stability. The highest improvement of 41.9% was reported for the 2 wt.% filler loading, making the nanocomposite suitable for applications requiring a high mechanical response in 3D printing, in which the matrix material cannot meet the design requirements.
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Repnin, Arseniy, Anton Sotov, Anatoliy Popovich, and Dmitriy Masaylo. "Development of TiO2/ZrO2 Multi-Material Obtained from Ceramic Pastes for Material Extrusion." Micromachines 14, no. 12 (2023): 2177. http://dx.doi.org/10.3390/mi14122177.
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The application of additive manufacturing method such as material extrusion (MEX) allows the successful fabrication of ceramic products, including multi-ceramic products. Promising materials in this research area are TiO2 and ZrO2 ceramics, which can be used in electrical and electronic engineering. The aim of this work is to investigate the possibility of fabricating TiO2/ZrO2 multi-materials from ceramic pastes that can be used in the MEX. In this work, defects, chemical and phase composition, and microhardness were analyzed in multi-ceramic samples after sintering. Multi-ceramic TiO2/ZrO2 samples after the sintering process without interlayer could not be fabricated due to a too large difference in shrinkage between TiO2 and ZrO2. The samples with one and three interlayers also have defects, but they are less significant and can be fabricated. The average hardness for the TiO2 zone was 636.7 HV and for the ZrO2 zone was 1101 HV. In the TiO2 zone, only TiO2 phase in rutile is observed, while in the interlayer zones, in addition to rutile, ZrO2 and ZrTiO4 are also present, as is a small amount of Y2O3. In the zone ZrO2, only the ZrO2 phase is observed. The chemical analysis revealed that the interlayers comprise sintered ZrO2 granules enveloped by TiO2, ZrO2, and ZrTiO4.
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Jasik, Katarzyna, Janusz Kluczyński, Danuta Miedzińska, et al. "Comparison of Additively Manufactured Polymer-Ceramic Parts Obtained via Different Technologies." Materials 17, no. 1 (2024): 240. http://dx.doi.org/10.3390/ma17010240.
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This paper aims to compare two ceramic materials available for additive manufacturing (AM) processes—vat photopolymerization (VPP) and material extrusion (MEX)—that result in fully ceramic parts after proper heat treatment. The analysis points out the most significant differences between the structural and mechanical properties and the potential application of each AM technology. The research revealed different behaviors for the specimens obtained via the two mentioned technologies. In the case of MEX, the specimens exhibited similar microstructures before and after heat treatment. The sintering process did not affect the shape of the grains, only their size. For the VPP specimens, directly after the manufacturing process, irregular grain shapes were registered, but after the sintering process, the grains fused, forming a solid structure that made it impossible to outline individual grains and measure their size. The highest compression strength was 168 MPa for the MEX specimens and 81 MPa for the VPP specimens. While the VPP specimens had half the compression strength, the results for the VPP specimens were significantly more repeatable.
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Santos, Cyril, Daniel Gatões, Fábio Cerejo, and Maria Teresa Vieira. "Influence of Metallic Powder Characteristics on Extruded Feedstock Performance for Indirect Additive Manufacturing." Materials 14, no. 23 (2021): 7136. http://dx.doi.org/10.3390/ma14237136.
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Material extrusion (MEX) of metallic powder-based filaments has shown great potential as an additive manufacturing (AM) technology. MEX provides an easy solution as an alternative to direct additive manufacturing technologies (e.g., Selective Laser Melting, Electron Beam Melting, Direct Energy Deposition) for problematic metallic powders such as copper, essential due to its reflectivity and thermal conductivity. MEX, an indirect AM technology, consists of five steps—optimisation of mixing of metal powder, binder, and additives (feedstock); filament production; shaping from strands; debinding; sintering. The great challenge in MEX is, undoubtedly, filament manufacturing for optimal green density, and consequently the best sintered properties. The filament, to be extrudable, must accomplish at optimal powder volume concentration (CPVC) with good rheological performance, flexibility, and stiffness. In this study, a feedstock composition (similar binder, additives, and CPVC; 61 vol. %) of copper powder with three different particle powder characteristics was selected in order to highlight their role in the final product. The quality of the filaments, strands, and 3D objects was analysed by micro-CT, highlighting the influence of the different powder characteristics on the homogeneity and defects of the greens; sintered quality was also analysed regarding microstructure and hardness. The filament based on particles powder with D50 close to 11 µm, and straight distribution of particles size showed the best homogeneity and the lowest defects.
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Meng, Fankai, Margherita Beretta, Jozef Vleugels, Frederik Desplentere, and Eleonora Ferraris. "Binder formulation and printing performance of zirconia filament feedstocks for material extrusion (MEX) additive manufacturing." Materials & Design 254 (June 2025): 114038. https://doi.org/10.1016/j.matdes.2025.114038.
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Drégelyi-Kiss, Ágota. "Application of Experimental Design-Based Predictive Models and Optimization in Additive Manufacturing – a Review." Hungarian Journal of Industry and Chemistry 52, no. 1 (2024): 55–70. http://dx.doi.org/10.33927/hjic-2024-08.
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Experiments play a crucial role in additive manufacturing to help researchers develop new materials with enhanced properties or in several types of process optimization tasks. Design of Experiments (DoE) is a valuable tool that is efficient, statistically rigorous and offers a systematic approach to experimentation. In this article, several types of DoE methods such as one-factor-at-a-time (OFAT), full and fractional factorial designs, Taguchi, response surface methodology (RSM) and descriptive screening designs (DSD) are briefly described in addition to some single- and multi-objective optimization methods. The optimization methods apply utility theory (UT), Taguchi and desirability optimization as well as some non-conventional, artificial intelligence-based multi-objective optimization methods illustrated by examples from the field of additive manufacturing. In the second part, the potential factors and response variables are reviewed during the investigation of the seven main categories of additive manufacturing, namely binder jetting (BJT), directed energy deposition (DED), material extrusion (MEX), material jetting (MJT), powder bed fusion (PBF), sheet lamination (SHL) and vat photopolymerization (VPP).
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Vidakis, Nectarios, Markos Petousis, Nikolaos Michailidis, et al. "High-Density Polyethylene/Carbon Black Composites in Material Extrusion Additive Manufacturing: Conductivity, Thermal, Rheological, and Mechanical Responses." Polymers 15, no. 24 (2023): 4717. http://dx.doi.org/10.3390/polym15244717.
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High-density polyethylene polymer (HDPE) and carbon black (CB) were utilized to create HDPE/CB composites with different filler concentrations (0.0, 2.0, 4.0, 6.0, 8.0, 10.0, 16.0, 20.0, and 24.0 wt.%). The composites were extruded into filaments, which were then utilized to fabricate 3D-printed specimens with the material extrusion (MEX) method, suitable for a variety of standard mechanical tests. The electrical conductivity was investigated. Furthermore, thermogravimetric analysis and differential scanning calorimetry were carried out for all the HDPE/CB composites and pure HDPE. Scanning electron microscopy in different magnifications was performed on the specimens’ fracture and side surfaces to investigate the morphological characteristics. Rheological tests and Raman spectroscopy were also performed. Eleven different tests in total were performed to fully characterize the composites and reveal connections between their various properties. HDPE/CB 20.0 wt.% showed the greatest reinforcement results in relation to pure HDPE. Such composites are novel in the MEX 3D printing method. The addition of the CB filler greatly enhanced the performance of the popular HDPE polymer, expanding its applications.
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Kluczyński, Janusz, Katarzyna Jasik, Jakub Łuszczek, et al. "A Comparative Investigation of Properties of Metallic Parts Additively Manufactured through MEX and PBF-LB/M Technologies." Materials 16, no. 14 (2023): 5200. http://dx.doi.org/10.3390/ma16145200.
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In this study, the research on 316L steel manufactured additively using two commercially available techniques, Material Extrusion (MEX) and Laser Powder Bed Fusion of Metals (PBF-LB/M), were compared. The additive manufacturing (AM) process based on powder bed synthesis is of great interest in the production of metal parts. One of the most interesting alternatives to PBF-LB/M, are techniques based on material extrusion due to the significant initial cost reduction. Therefore, the paper compares these two different methods of AM technologies for metals. The investigations involved determining the density of the printed samples, assessing their surface roughness in two printing planes, examining their microstructures including determining their porosity and density, and measuring their hardness. The tests carried out make it possible to determine the durability, and quality of the obtained sample parts, as well as to assess their strength. The conducted research revealed that samples fabricated using the PBF-LB/M technology exhibited approximately 3% lower porosity compared to those produced using the MEX technology. Additionally, it was observed that the hardness of PBF-LB/M samples was more than twice as high as that of the samples manufactured using the MEX technology.
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Slattery, Lucinda K., Zackery B. McClelland, and Samuel T. Hess. "Process–Structure–Property Relationship Development in Large-Format Additive Manufacturing: Fiber Alignment and Ultimate Tensile Strength." Materials 17, no. 7 (2024): 1526. http://dx.doi.org/10.3390/ma17071526.
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Parts made through additive manufacturing (AM) often exhibit mechanical anisotropy due to the time-based deposition of material and processing parameters. In polymer material extrusion (MEX), printed parts have weak points at layer interfaces, perpendicular to the direction of deposition. Poly(lactic acid) with chopped carbon fiber was printed on a large-format pellet printer at various extrusion rates with the same tool pathing to measure the fiber alignment with deposition via two methods and relate it to the ultimate tensile strength (UTS). Within a singular printed bead, an X-ray microscopy (XRM) scan was conducted to produce a reconstruction of the internal microstructure and 3D object data on the length and orientation of fibers. From the scan, discrete images were used in an image analysis technique to determine the fiber alignment to deposition without 3D object data on each fiber’s size. Both the object method and the discrete image method showed a negative relationship between the extrusion rate and fiber alignment, with −34.64% and −53.43% alignment per extrusion multiplier, respectively, as the slopes of the linear regression. Tensile testing was conducted to determine the correlation between the fiber alignment and UTS. For all extrusion rates tested, as the extrusion multiplier increased, the percent difference in the UTS decreased, to a minimum of 8.12 ± 14.40%. The use of image analysis for the determination of the fiber alignment provides a possible method for relating the microstructure to the meso-property of AM parts, and the relationship between the microstructure and the properties establishes process–structure–property relationships for large-format AM.
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Kuschmitz, Sebastian, Tobias P. Ring, Hagen Watschke, Sabine C. Langer, and Thomas Vietor. "Design and Additive Manufacturing of Porous Sound Absorbers—A Machine-Learning Approach." Materials 14, no. 7 (2021): 1747. http://dx.doi.org/10.3390/ma14071747.
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Additive manufacturing (AM), widely known as 3D-printing, builds parts by adding material in a layer-by-layer process. This tool-less procedure enables the manufacturing of porous sound absorbers with defined geometric features, however, the connection of the acoustic behavior and the material’s micro-scale structure is only known for special cases. To bridge this gap, the work presented here employs machine-learning techniques that compute acoustic material parameters (Biot parameters) from the material’s micro-scale geometry. For this purpose, a set of test specimens is used that have been developed in earlier studies. The test specimens resemble generic absorbers by a regular lattice structure based on a bar design and allow a variety of parameter variations, such as bar width, or bar height. A set of 50 test specimens is manufactured by material extrusion (MEX) with a nozzle diameter of 0.2 mm and a targeted under extrusion to represent finer structures. For the training of the machine learning models, the Biot parameters are inversely identified from the manufactured specimen. Therefore, laboratory measurements of the flow resistivity and absorption coefficient are used. The resulting data is used for training two different machine learning models, an artificial neural network and a k-nearest neighbor approach. It can be shown that both models are able to predict the Biot parameters from the specimen’s micro-scale with reasonable accuracy. Moreover, the detour via the Biot parameters allows the application of the process for application cases that lie beyond the scope of the initial database, for example, the material behavior for other sound fields or frequency ranges can be predicted. This makes the process particularly useful for material design and takes a step forward in the direction of tailoring materials specific to their application.
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Prajapati, Mayur Jiyalal, Chinmai Bhat, Ajeet Kumar, Saurav Verma, Shang-Chih Lin, and Jeng-Ywan Jeng. "Supportless Lattice Structure for Additive Manufacturing of Functional Products and the Evaluation of Its Mechanical Property at Variable Strain Rates." Materials 15, no. 22 (2022): 7954. http://dx.doi.org/10.3390/ma15227954.
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This study proposes an innovative design solution based on the design for additive manufacturing (DfAM) and post-process for manufacturing industrial-grade products by reducing additive manufacturing (AM) time and improving production agility. The design of the supportless open cell Sea Urchin lattice structure is analyzed using DfAM for material extrusion (MEX) process to print support free in any direction. The open cell is converted into a global closed cell to entrap secondary foam material. The lattice structure is 3D printed with Polyethylene terephthalate glycol (PETG) material and is filled with foam using the Hybrid MEX process. Foam-filling improves the lattice structure’s energy absorption and crash force efficiency when tested at different strain rates. An industrial case study demonstrates the importance and application of this lightweight and tough design to meet the challenging current and future mass customization market. A consumer-based industrial scenario is chosen wherein an innovative 3D-printed universal puck accommodates different shapes of products across the supply line. The pucks are prone to collisions on the supply line, generating shock loads and hazardous noise. The results show that support-free global closed-cell lattice structures filled with foam improve energy absorption at a high strain rate and enhance the functional requirement of noise reduction during the collision.
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Consul, Patrick, Matthias Feuchtgruber, Bernhard Bauer, and Klaus Drechsler. "Influence of Extrusion Parameters on the Mechanical Properties of Slow Crystallizing Carbon Fiber-Reinforced PAEK in Large Format Additive Manufacturing." Polymers 16, no. 16 (2024): 2364. http://dx.doi.org/10.3390/polym16162364.
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Additive Manufacturing (AM) enables the automated production of complex geometries with low waste and lead time, notably through Material Extrusion (MEX). This study explores Large Format Additive Manufacturing (LFAM) with carbon fiber-reinforced polyaryletherketones (PAEK), particularly a slow crystallizing grade by Victrex. The research investigates how extrusion parameters affect the mechanical properties of the printed parts. Key parameters include line width, layer height, layer time, and extrusion temperature, analyzed through a series of controlled experiments. Thermal history during printing, including cooling rates and substrate temperatures, was monitored using thermocouples and infrared cameras. The crystallization behavior of PAEK was replicated in a Differential Scanning Calorimetry (DSC) setup. Mechanical properties were evaluated using three-point bending tests to analyze the impact of thermal conditions at the deposition interface on interlayer bonding and overall part strength. The study suggests aggregated metrics, enthalpy deposition rate and shear rate under the nozzle, that should be maximized to enhance mechanical performance. The findings show that the common practice of setting fixed layer times falls short of ensuring repeatable part quality.
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Asami, Karim, Sebastian Roth, Jan Hünting, Tim Röver, and Claus Emmelmann. "Metallic Bipolar Plate Production Through Additive Manufacturing: Contrasting MEX/M and PBF-LB/M Approaches." Journal of Experimental and Theoretical Analyses 3, no. 2 (2025): 12. https://doi.org/10.3390/jeta3020012.
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Additive manufacturing (AM) technologies have witnessed remarkable advancements, offering opportunities to produce complex components across various industries. This paper explores the potential of AM for fabricating bipolar plates (BPPs) in fuel cell or electrolysis cell applications. BPPs play a critical role in the performance and efficiency of such cells, and conventional manufacturing methods often face limitations, particularly concerning the complexity and customization of geometries. The focus here lies in two specific AM methods: the laser powder bed fusion of metals (PBF-LB/M) and material extrusion of metals (MEX/M). PBF-LB/M, tailored for high-performance applications, enables the creation of highly complex geometries, albeit at increased costs. On the other hand, MEX/M excels in rapid prototyping, facilitating the swift production of diverse geometries for real-world testing. This approach can facilitate the evaluation of geometries suitable for mass production via sinter-based manufacturing processes. The geometric deviations of different BPPs were identified by evaluating 3D scans. The PBF-LB/M method is more suitable for small features, while the MEX/M method has lower deviations for geometrically less complex BPPs. Through this investigation, the limits of the capabilities of these AM methods became clear, knowledge that can potentially enhance the design and production of BPPs, revolutionizing the energy conversion and storage landscape and contributing to the design of additive manufacturing technologies.
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Leubecher, Dominik, Steffen Brier, Pablo Vitale, Bruno Musil, and Philipp Höfer. "Crystallisation Dynamics in Large-Scale Extrusion Additive Manufacturing: An Analysis with and without Temperature Modification." Materials 17, no. 10 (2024): 2243. http://dx.doi.org/10.3390/ma17102243.
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Large-Scale Material Extrusion (LS-MEX) is increasingly being used in small-scale production and prototyping due to its ability to create components in new temporal and spatial dimensions. However, the use of this manufacturing process poses microscopic and macroscopic challenges not encountered in previous small-scale production systems. These challenges arise primarily from the prolonged retention of heat in the material, which leads to insufficient strength in the extruded strands at the macrostructural level. As a result, the component can collapse, a phenomenon known as ‘slumping’. Thermal energy also influences microstructural changes, such as crystallisation kinetics, which affect properties such as the strength and stiffness of the final product. The duration and dynamics of thermal energy are influenced by manufacturing parameters and the possible use of additional peripheral equipment, which affects component quality. In this study, the influence of thermal energy on structural processes through simulations of polyamide 6 with 40% carbon fibres (PA6 wt.%40 CF) is investigated. The results show that by adjusting the process parameters and using modification units, the thermal profile of the material can be accurately controlled, which allows the microstructural processes to be precisely controlled. This leads to the targeted modification of the macroscopic material properties. The focus of this work is on the combination of numerical simulations of the LS-MEX process with semi-empirical methods for the analysis of crystallisation processes. The application of the Nakamura model, which is used throughout similar investigations, allows a detailed description and prediction of the crystallisation kinetics during the manufacturing process. The study shows that the absolute degree of crystallisation can be determined with simplified assumptions using a combination of thermal simulations and semi-empirical approaches. It was found that the absolute degree of crystallisation increases from the outer interface of the strand to the print bed across the cross-section. This can be attributed to the specific thermal boundary conditions and the resulting temperature profiles at different points.
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Hwang, Ji Yong, Seong Je Park, Yong Son, and Hyo Yun Jung. "Influence of In Situ Magnetic Field on Magnetic Properties of a Bonded Permanent Magnet Manufactured through Material Extrusion Additive Manufacturing." Metals 13, no. 10 (2023): 1653. http://dx.doi.org/10.3390/met13101653.
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In this study, a material extrusion (MEX) nozzle for fabricating bond magnets was designed to form a unidirectional magnetic field with a solenoid. The hard magnetic properties of the bonded magnets were enhanced by induced magnetic anisotropy. The magnetic field strength for magnetic alignment was controlled by the current applied to the solenoid, and the magnetic field strength formed at the bottom of the solenoid was approximately 10 mT. When a magnetic field was applied to the magnetic particles in filaments, magnetic spins and domains that existed in spherical magnetic particles were magnetically rotated and preferentially aligned with the induced magnetic field. Subsequently, as the polymer matrix was softened by the heat generated by the current induced in the solenoid, bonded magnets were additively manufactured using MEX with in situ magnetic field, and hard magnetic properties such as coercivity, remanence, and maximum energy product of the manufactured magnets were confirmed to be enhanced. The improvement in hard magnetic properties was attributed to the increased magnetic anisotropy caused by magnetic alignment. Based on the results of this study, we expect MEX with a magnetic field application system to be used in the future for manufacturing complex-shaped bonded magnets with improved magnetic properties.
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Cañadilla, Antonio, Gloria Rodríguez, Ana Romero, Miguel A. Caminero, and Oscar J. Dura. "Sustainable production of copper components using concentrated solar energy in material extrusion additive manufacturing (MEX-CSE)." Sustainable Materials and Technologies 39 (April 2024): e00799. http://dx.doi.org/10.1016/j.susmat.2023.e00799.
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