1,721,080 research outputs found
A preliminary study on multi‐material fused filament fabrication of an embedded strain gauge for low‐cost real‐time monitoring of part strain
Full text linkUnlike other manufacturing techniques, additive manufacturing enables part consolidation through the production of multi- material parts with enhanced functionality. With reference to the functionality of monitoring the structural integrity of a product during its use, conductive filaments can be used in additive manufacturing. This work aims to investigate the appli- cations of multi-material fused filament fabrication to produce embedded strain gauges for real-time monitoring of part deformations. In layer-by-layer fabrication, conductive filaments can be used to produce strain-sensitive elements inside products at a low cost. This preliminary study demonstrated the feasibility of the proposed approach using tensile samples fabricated through additive manufacturing. The samples were produced using a polyethylene terephthalate glycol filament and an acrylonitrile styrene acrylate filament, while electrically conductive polylactic acid was used for the strain gauge. The characterization and testing activities were conducted by comparing the results of the tensile testing with data acquired through an experimental system set up with an Arduino board, aligning with the resistance-based strain gauge theory. The findings show that the co-fabricated strain gauge successfully traces part deformation, enabling real-time monitoring of strain in the elastic field. Nevertheless, further optimization of the proposed approach is imperative to enhance the reliability and accuracy of the methodology
Multimaterial 3D printing of auxetic jounce bumpers for automotive suspensions
Full text linkPurpose – The purpose of this study is to evaluate the 3D printability of a multimaterial, fully self-supporting auxetic structure. This will contribute to expanding the application of additive manufacturing (AM) to new products, such as automotive suspensions.
Design/methodology/approach – An experimental approach for sample fabrication on a multiextruder 3D printer and characterization by compression testing was conducted along with numerical simulations, which were used to support the design of different auxetic configurations for the jounce bumper.
Findings – The effect of stacking different auxetic cell modules was discussed, and the findings demonstrated that a one-piece printed structure has a better performance than one composed of multiple single modules stacked on top of each other.
Research limitations/implications – The quality of the 3D printing process affected the performance of the final components and reproducibility of the results. Therefore, researchers are encouraged to further study component fabrication optimization to achieve a more reliable process.
Practical implications – This research work can help improve the manufacturing and functionality of a critical element of automotive suspension systems, such as the jounce bumper, which can efficiently reduce noise, vibration and harshness by absorbing impact energy.
Originality/value – In previous research, auxetic structures for the application of jounce bumpers have already been suggested. However, to the best of the authors’ knowledge, in this work, an AM approach was used for the first time to fabricate multimaterial auxetic structures, not only by co-printing a flexible thermoplastic polymer with a stiffer one but also by continuously extruding multilevel structures of auxetic cell modules
Assessment of simulation software for predicting induced distortions in laser-beam powder bed fusion of Ti6Al4V
No full textThe right first time (RFT) in the laser-beam powder bed fusion of metal powder (PBF-LB/M) process refers to achieving optimal part quality and minimal distortions in the first manufacturing attempt, which is critical for enhancing productivity and sustainability. This is particularly challenging due to the internal stresses and thermal gradients inherent to the process, which lead to significant distortions. This study addresses the challenge of predicting and mitigating these distortions for Ti6Al4V parts in the PBF-LB/M process. Calibration tests and experimental validations using Amphyon software were conducted, with the process involving software calibration, sensitivity analysis, and simulation validation through reverse engineering tools. Additionally, a pre-compensation method was applied to monitor and reduce distortion. The results demonstrated that Amphyon can predict distortions with a maximum deviation of up to 14% between simulated and experimental results, while pre-compensation reduces deformation by up to 70%. Finally, the simulation approach was validated through a real-world application, fabricating a cranial medical implant, showcasing its practical relevance. This work highlights the potential of simulation tools for optimizing PBF-LB/M processes, improving accuracy, and reducing material waste in industrial applications
Effect of annealing treatment and infill percentage on 3D-printed PEEK samples by Fused Filament Fabrication
Full text linkA strategy that is gaining momentum in several industrial sectors is metal replacement, which aims to find suitable alternatives for replacing metal components with lighter ones. One possible solution is represented by high-performance polymers (HPP), which are a family of materials with improved thermo-mechanical and functional properties, compared to commodity plastics. Additive manufacturing (AM) is revolutionizing the industrial world due to its high design freedom, dimensional accuracy, and shortened total production time. Thus, combining the use of HPP with AM technologies could lead to innovative results, which could offer new metal replacement solutions through redesign and new material properties. However, HPPs have some manufacturing limitations, for example, they require high processing temperatures, and some of them
are subject to significant warping and deformation phenomena. This aspect is particularly significant for semi-crystalline polymers, as in the case of poly(ether-ether-ketone) (PEEK), which is affected by thermal gradients during 3D printing. In this research, an investigation was carried out on the Fused Filament Fabrication (FFF) of different 3D printed PEEK samples, evaluating the effect on final properties not only of various infill percentages (30%, 50%, 70%, and 100%) but also of two different heating treatments. In this regard, a traditional annealing in oven, post 3D printing, was compared to a direct annealing approach, performed during FFF. The mechanical performance of the samples was characterized through tensile and compression tests along with the thermal properties and the thermal stability. In addition, for all different cases, energy consumption was measured, to provide an indication of the sustainability of the presented approaches. The findings suggest that the direct annealing solution holds promise and merits further investigation to bridge knowledge gaps in this domain.
This research contributed to advance the understanding of PEEK 3D printing by FFF and played a vital role in the practical implementation of metal replacement as a sustainable strategy across various industrial applications
Influence of Process Parameters on Compression Properties of 3D Printed Polyether-Ether-Ketone by Fused Filament Fabrication
No full textMetal replacement is an effective approach for sustainable manufacturing of polymer products in various sectors with the key advantage of reducing the component weight. Technopolymers are a class of materials with increased properties, i.e., thermal and chemical stability as well as mechanical resistance, compared to traditional plastics, thus resulting in a more efficient alternative for metal parts. Nowadays, Additive Manufacturing is a game-changer production technology due to its high flexibility, geometrical accuracy, reduced time and costs, and minimal waste. Therefore, an attractive research topic for technopolymers is their application in Additive Manufacturing. Polyether-ether-ketone (PEEK) is a semi-crystalline technopolymer, its thermal susceptibility during the cooling step of the process remains the dominant cause of dimensional warping and job failure. The nozzle and bed/chamber temperature difference should be optimised to reduce the thermal gradient. Previous researchers investigated the nozzle and bed temperature effects deeply. However, the chamber temperature influence on the dimensional accuracy and compression properties is still missing in the literature, particularly for samples printed with an infill lower than 100%. Therefore, this study aims to fill these gaps and deepen the knowledge about PEEK printing via Fused Filament Fabrication by evaluating the effects of chamber temperature and infill percentage over compression properties, printing accuracy and energy consumption. The specific compression properties highlighted that the highest values were reached for not fully dense samples. Furthermore, the heating chamber did not affect the dimensional accuracy and compressive properties as strongly to justify an energy consumption increment of 45%
Additive Manufacturing of a PA11 Prototype Fabricated via Selective Laser Sintering for Advanced Industrial Applications
Full text linkSelective Laser Sintering (SLS) is an Additive Manufacturing (AM) technology that is receiving considerable attention in the scientific and industrial communities due to its great ability to efficiently produce functional and complex parts. The present work aims to fabricate a real prototype via SLS, such as a hose reel for industrial applications, using polyamide 11 (PA11) as a starting material. Characterization of the PA11 powder properties was first carried out from a thermal and morphological viewpoint to determine the powder’s thermal stability by TGA, the sintering window and degree of crystallinity by DSC, and the microstructure by SEM, PSD, and XRD analyses. The results revealed that PA11 has a 45-micron average particle size, circularity close to 1, and a Hausner ratio of 1.17. Together, these parameters ensure that PA11 powder flows smoothly, packs uniformly, and forms dense and defect-free layers during the SLS process, directly contributing to high part quality, dimensional precision, and stable process performance. The printability of the PA11 was optimized for the realization of 3D-printed parts for industrial applications. Finally, the quality of the printed samples and the mechanical and thermal performance were investigated. Several PA11-based parts were fabricated via SLS, showing a high level of complexity and definition, ideal for industrial applications, as confirmed by the predominantly green areas of the colored maps of X-CT. A complete prototypal case for a hose reel was assembled by using the parts realized, and it was chosen as a technological demonstrator to verify the feasibility of PA11 powder in the production of industrial professional components
Characterization of biocompatible scaffolds manufactured by fused filament fabrication of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate
Full text linkWe characterize poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) scaffolds for tissue repair and regeneration, manufactured by three-dimensional fused filament fabrication (FFF). PHBH belongs to the class of polyhydroxyalkanoates with interesting biodegradable and biocompatible capabilities, especially attractive for tissue engineering. Equally, FFF stands as a promising manufacturing technology for the production of custom-designed scaffolds. We address thermal, rheological and cytotoxicity properties of PHBH, placing special emphasis on the mechanical response of the printed material in a wide deformation range. Indeed, effective mechanical properties are assessed in both the linear and nonlinear regime. To warrant uniqueness of the material parameters, these are measured directly through digital image correlation, both in tension and compression, while experimental data fitting of finite-element analyses is only adopted for the determination of the second invariant coefficient in the nonlinear regime. Mechanical data are clearly porosity dependent, and they are given for both the cubic and the honeycomb infill pattern. Local strain spikes due to the presence of defects are observed and measured: those falling in the range 70–100% lead to macro-crack development and, ultimately, to failure. Results suggest the significant potential attached to FFF printing of PHBH for customizable medical devices which are biocompatible and mechanically resilient
Characterization of 3D Printed Polylactic Acid by Fused Granular Fabrication through Printing Accuracy, Porosity, Thermal and Mechanical Analyses
Full text linkFused Granular Fabrication (FGF) or screw-extrusion based 3D printing for polymers is a less diffused alternative to filament-based Additive Manufacturing (AM). Its greatest advantage lies in superior sustainability; in fact, polymer granules can be used to directly feed an FGF printer, reducing the time, cost and energy of producing a part. Moreover, with this technology, a circular economy approach involving the use of pellets made from plastic waste can be easily implemented. Polylactic Acid (PLA) pellets were processed at different printing speeds and with different infill percentages on a customized version of a commercial Prusa i3 Plus 3D printer modified with a Mahor screw extruder. For the characterization of the 3D printed samples, rheological, thermal, mechanical and porosity analyses were carried out. In addition, the energy consumption of the 3D printer was monitored during the production of the specimens. The results showed that a higher printing speed leads to lower energy consumption, without compromising material strength, whereas a slower printing speed is preferable to increase material stiffness
Evaluating Self-Produced PLA Filament for Sustainable 3D Printing: Mechanical Properties and Energy Consumption Compared to Commercial Alternatives
Full text linkThis study investigates the feasibility of self-producing polylactic acid (PLA) filament for use in 3D printing. The filament was fabricated using a desktop single-screw extruder and evaluated against commercially available PLA in terms of mechanical properties and energy consumption. Specimens were printed at two layer heights (0.2 mm and 0.3 mm) and four infill densities (25%, 50%, 75%, and 100%). The self-produced filament exhibited lower diameter precision (1.67 ± 0.21 mm), which resulted in mass variability up to three orders of magnitude higher than that of the commercial filament. Thermal analysis confirmed that the extrusion and printing process did not significantly alter the thermal properties of PLA. Mechanical testing revealed that a layer height 0.3 mm consistently yielded higher stiffness and tensile strength in all samples. When normalized by mass, the specimens printed with commercial filament demonstrated approximately double the ultimate tensile strength compared to those that used self-produced filament. The energy consumption analysis indicated that a 0.3 mm layer height improved printing efficiency, cutting specific energy consumption by approximately 50% and increasing the material deposition rate proportionally. However, the total energy required to print with self-produced filament was nearly three times higher than that for commercial filament, primarily due to material waste that stems from inconsistencies in the diameter of the filament. These findings are significant in evaluating the practicality of self-produced PLA filament, particularly in terms of mechanical performance and energy efficiency
Valorization of Winery By-Products as Bio-Fillers for Biopolymer-Based Composites
Full text linkGrape seeds (GS), wine lees (WL), and grape pomace (GP) are common winery by-products, used as bio-fillers in this research with two distinct biopolymer matrices - poly(butylene adipate-co-terephthalate) (PBAT) and polybutylene succinate (PBS) -to create fully bio-based composite materials. Each composite included at least 30 v% bio-filler, with a sample reaching 40 v%, as we sought to determine a composition that could be economically and environmentally effective as a substitute for a pure biopolymer matrix. The compounding process employed a twin-screw extruder followed by an injection molding procedure to fabricate the specimens. An acetylation treatment assessed the specimen’s efficacy in enhancing matrix–bio-filler affinity, particularly for WL and GS. The fabricated bio-composites underwent an accurate characterization, revealing no alteration in thermal properties after compounding with bio-fillers. Moreover, hygroscopic measurements indicated increased water-affinity in bio-composites compared to neat biopolymer, most significantly with GP, which exhibited a 7-fold increase. Both tensile and dynamic mechanical tests demonstrated that bio-fillers not only preserved, but significantly enhanced, the stiffness of the neat biopolymer across all samples. In this regard, the most promising results were achieved with the PBAT and acetylated GS sample, showing a 162% relative increase in Young’s modulus, and the PBS and WL sample, which exhibited the highest absolute values of Young’s modulus and storage modulus, even at high temperatures. These findings underscore the scientific importance of exploring the interaction between bio-fillers derived from winery by-products and three different biopolymer matrices, showcasing their potential for sustainable material development, and advancing polymer science and bio-sourced material processing. From a practical standpoint, the study highlighted the tangible benefits of using by-product bio-fillers, including cost savings, waste reduction, and environmental advantages, thus paving the way for greener and more economically viable material production practices
- …
