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The increasing electromagnetic pollution due to the widespread use of electronic devices has drawn attention to the development of high-efficiency electromagnetic wave absorption materials. In this study, polypropylene (PP)/Ni composite materials were prepared using the fused deposition modeling method, with PP as the matrix. The mechanical and absorption properties were investigated, showing that the PP-based materials exhibited good mechanical performance with a tensile strength of 25.3 MPa and an elongation at break of 32.1%. At a Ni content of 50% and a thickness of 1.9 mm, the composite material showed absorption properties of −24.31 dB and 5.6 GHz. The absorption bandwidth covered the entire X and Ku bands (6.4–18 GHz) with adjustable thickness ranging from 1.5 to 4 mm. The combination of excellent absorption and mechanical properties makes these materials promising for the fabrication of complex absorber devices. [ABSTRACT FROM AUTHOR]

Fused deposition modeling (FDM), an economical additive manufacturing (AM) technique, is widely used for extruding thermoplastic filaments. Acrylonitrile butadiene styrene (ABS) is a widely used polymer for FDM technique due to its inexpensive cost, strong impact strength, great durability, and intriguing uses. ABS materials are used for interior parts of automotive applications, drug-delivery systems, tracheal tubes, valves for ventilators, and medical masks. Nonetheless, shrinkage and warping are the primary weaknesses of ABS during the FDM process, affecting the dimensional stability of printed parts. In this context, a patent-pending radiant heating system has been developed to improve the overall performance of printed parts. This study aimed to evaluate the effect of in situ thermal treatment on the interlayer adhesion and mechanical properties of printed ABS parts. The thermal treatment was carried out on a radiant heating system at 240 °C and a printing speed of 35 mm·s−1. The physical and mechanical properties of ABS parts printed with and without radiant heating were then characterized. Various techniques, including tensile tests, X-ray microtomography (µ-CT), optical profilometry (OP), atomic force microscopy (AFM), and dynamic mechanical analysis (DMA), were conducted to investigate mechanical, microstructural, and topological properties of printed ABS parts. The results show that treated samples exhibit better interlayer adhesion than untreated ones. In addition, the treated samples had a lower porosity (1.6%) than the untreated samples (3%). Furthermore, the tensile strength, elastic modulus, and elongation at break of treated samples increased by 62%, 6%, and 110%, respectively, compared to untreated ones. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate the variation in the shape memory effect in the Tan Delta output parameter of shape memory polymeric stents, fabricated by the bio-FDM process, during a reversible endothermic cycle with changes in the input parameters. Pure polycaprolactone polymer was directly used in this study. The Damping Factor, or Tan Delta, is a key factor in expressing the shape memory effect of the memory stents. For a more accurate evaluation of this effect, SEM tests, uniaxial tensile tests, and dynamic mechanical and thermal analyses were employed. The Tan Delta of the shape memory stents was approximately 18.81%. Surface morphology changes led to approximately a 14.18% variation in elastic properties, as the dynamic molecular motion and polymer chain constraints resulted in increased pressure. It was found that the fabrication input parameters led to approximately a 20% change in the shape memory effect. [ABSTRACT FROM AUTHOR]

Continuous research in the field of metal additive manufacturing has led to the need for constant improvement of manufacturing parameters especially in the case of FDM (Fused Deposition Modeling) manufacturing. In recent years, the main directions outlined for productivity and quality improvement were related to higher printing speed and the use of ironing-type processes. This article aims to study the manufacturing parameters of the dimensional accuracy and surface quality of FDM-manufactured 316L stainless steel. The degree of novelty is given by the application of the ironing process for the green part. A full factorial 33 experimental design was designed for this study, in which the factors studied were ironing angle, ironing speed, and layer spacing during ironing. The dimensional accuracy and surface roughness were analyzed by means of deviation measurement from CAD to the green part and final part after the sintering process. Using the design of experiments offers the possibility of applying the analysis of variance (ANOVA) which provides information about the degree of influence of each of the studied factors. The results obtained for the dimensional accuracy showed that the ironing direction had the biggest influence on the Z-axis shrinkage. Overall, approximately 6% shrinkage in the Z and Y directions was obtained while in the X directions, the shrinkage percentage was around 20%. Surface roughness showed an improvement with higher ironing speeds for the green part while for the sintered part the most significant factor was ironing spacing. [ABSTRACT FROM AUTHOR]

3D printing has revolutionized product design and manufacturing across various industries by enabling the creation of complex geometries with minimal waste. Despite its advancements, 3D printing still faces significant challenges, including spatial constraints and process control limitations. This paper introduces novel approaches to improve the functionality and precision of material extrusion 3D printers for the fused deposition modeling method, particularly for additional printing tasks such as printing on existing objects or continuing a print on a relocated object without prior knowledge of its position or even the environment is changed. We introduce a compensation system integrating a high-speed vision system for robot arms to address these challenges. Our system employs a three-step pose estimation process—fast point feature histograms (FPFH)-based, corner-based, and sub-pixel edge-based methods—to ensure high accuracy in restoring the position of printed pieces for additional printing tasks on a given object. Experimental results demonstrate substantial improvements in printing precision, with the system achieving sub-millimeter and sub-pixel accuracy. These advancements not only eliminate work area constraints but also enhance the adaptability and reliability of 3D printing processes. [ABSTRACT FROM AUTHOR]

In this study, a silane-treated sunn hemp fiber in a polyester resin and rubber seed husk cellulose toughened Acrylonitrile butadiene styrene honeycomb core were used to create a high-toughness, sudden energy-absorbing, environmentally sustainable composite. Materials include polyester resin, sunn hemp fiber, silane-treated cellulose derived from rubber seed husks, and methyl ethyl ketone peroxide as a catalyst. Using a fused deposition modeling printer, the honeycomb structure is manufactured. The composite materials were created by hand layup and post-cured for 48 h at 120 °C. The cured composites were then characterized in compliance with the American Society for Testing and Materials guidelines. The incorporation of 30% sunn hemp fiber and 10% ABS considerably improves the composites' fatigue behavior, impact resistance, and mechanical properties. According to the results, the composite containing 4.0 phr of silane-treated cellulose is noteworthy for achieving maximum values of 5.8 J for Izod impact, 209 MPa for flexural strength, 7.7 GPa for tensile strength, and 8.24 GPa for flexural modulus. In a comparable way, the composite RAC5 with a 4.0 phr cellulose content generated a maximum fatigue count of 27,841 for 25% of UTS throughout its fatigue cycles. Significant improvements were observed in the thermal stability, with the decomposition temperatures rising as high as 541 °C. The inclusion of reinforcements treated with silane resulted in improved bonding with polyester resin, as confirmed by the SEM study. According to the study's findings, these composites, which are distinguished by their excellent performance, low weight, and durability, have prospective uses in the automotive, sports, construction, and UAV industries. [ABSTRACT FROM AUTHOR]

This article examines the influence of various factors on the precision of 3D printed objects produced through Fused Filament Fabrication (FFF) using Polylactic Acid (PLA) as the primary material. While PLA is widely chosen for its compatibility with biological applications, it does suffer from limited dimensional accuracy. The study focuses on investigating the effects of four independent parameters, namely layer height, infill density, printing speed, and the number of top and bottom layers, on accuracy along the three axes of length, width, and depth. The research objective is to identify the optimal levels of these parameters that minimize dimensional errors across all axes. However, due to conflicting requirements among different dimensions, determining a comprehensive decision-making methodology presents a significant challenge. To address this issue, three distinct approaches are proposed, each offering a unique perspective and practical application. Interestingly, the outcomes of these approaches converge on a single solution. Among these parameters, printing speed emerges as the dominant factor, while, the number of layers is the least influential. Moreover, consistent shrinkage is observed in the length and width dimensions, with greater errors evident in longer dimensions. Overall, a preference for lower layer height and infill density, along with higher printing speed and increased top and bottom layers, is recommended. The study findings indicate that the most effective parameter selection for reducing errors in all dimensions involves a layer height of 0.2 mm, infill density of 60%, printing speed of 50 mm/s, and the use of four top and bottom layers. [ABSTRACT FROM AUTHOR]

Microneedles are an emerging class of transdermal drug delivery systems for biomedical applications. These devices allow minimally invasive and painless drug delivery, making them an attractive alternative to hypodermic injections. This paper focuses on the study of polymer‐based solid microneedles fabrication process using the fused deposition modeling (FDM) method. Biodegradable and biocompatible polymers are selected as printing materials. For this study, the thermoplastic polylactic acid (PLA), currently used for FDM microneedle preparation was selected. To overcome the potential brittleness of PLA during transdermal application, two other materials are also studied: polycaprolactone (PCL) and a PLA/PCL blend. The effect of 3D printing parameters on the dimensional accuracy of the microneedles is studied to determine the optimum printing conditions for each filament. In addition, the dimensions and/or geometry of the microneedles are modified to print its with minimal dimensions. Then, a post‐fabrication chemical etching treatment is used to improve both, size and shape of the printed solid microneedles. [ABSTRACT FROM AUTHOR]

This work studied the influence of process parameters (i.e., numerical factors, such as printing speed, immersion time, and built platform temperature; categorical factor, such as plane orientation type) on fused filament fabrication (FFF) process. The experimental study was conducted using a D-optimal four-factor design (three numerical and one categorical) design based on the response surface methodology. Samples were fabricated on an FFF machine, and tests were conducted to measure volumetric shrinkage and surface roughness. The experimental data were evaluated through analysis of variance and fitted to a second-order polynomial equation using the multiple regression method. The optimal conditions for minimizing both responses were identified by numerical optimization using the desirability function approach. Finally, a confirmatory analysis was performed using optimized parameter values that demonstrated a strong response to the predicted model. Under optimal conditions, the SEM micrographs of the cut surface revealed a decrease in distortion. Findings demonstrated that the response surface methodology based D-optimal approach was effectively utilized for modeling FFFed specimens and proved to be cost-effective in collecting the highest amount of information in the shortest period of time with the fewest possible number of experimental tests. [ABSTRACT FROM AUTHOR]

In recent years, plastic and metal 3D printing has experienced massive development in the professional and hobby spheres, especially for rapid prototyping, reverse engineering, maintenance and quick repairs. However, this technology is limited by a number of factors, with the most common being the cost and availability of the technology but also the lack of information on material properties. This study focuses on investigating the material properties of PLA, PETG, HIPS, PA, ABS and ASA in order to elucidate their behavior in terms of wear and thermal resistance. The research builds on previous studies focusing on the mechanical properties of these materials and includes wear testing and DMA analysis. Weight loss, frictional forces, and frictional work including relative frictional work are recorded as part of this testing. The storage modulus and loss modulus including tan(δ) were then measured using DMA. [ABSTRACT FROM AUTHOR]

In this work, the mechanical and dynamic thermomechanical properties of PEEK based on FDM are experimentally investigated and evaluated comprehensively. The tensile failure mechanism of PEEK prepared by FDM and extrusion modeling (EM) was analyzed by fracture morphology observation. By conducting a differential scanning calorimetry (DSC) test, the crystallinity of PEEK prepared by FDM and EM was measured. The dynamic thermomechanical properties of PEEK were tested and analyzed by dynamic mechanical analysis (DMA). For FDM-prepared PEEK samples, the yield strength and elongation were 98.3 ± 0.49 MPa and 22.86 ± 2.12%, respectively. Compared with the yield strength of PEEK prepared by EM, the yield strength of PEEK prepared by FDM increased by 65.38%. The crystallinity of FDM-prepared and EM-prepared samples was calculated as 34.81% and 31.55%, respectively. Different processing methods resulted in differences in the microscopic morphology and crystallinity of two types of PEEK parts, leading to differences in mechanical properties. The internal micropores generated during the FDM processing of PEEK significantly reduced the elongation. Moreover, according to the DMA results, the glass transition activation energy of PEEK was obtained as ΔE = 685.07 kJ/mol based on the Arrhenius equation. Due to the excellent mechanical properties of PEEK prepared by FDM processing, it is promising for high-performance polymer applications in different fields. [ABSTRACT FROM AUTHOR]

This study investigates the flexural behavior of 3D-printed multi-topology lattice beams, with a specific emphasis on octet and cube lattice geometries created through fused deposition modeling (FDM). The mechanical properties of these beams were evaluated through quasi-static three-point bending tests. A comparative analysis of load-carrying capacity, energy absorption, and specific energy absorption (SEA) indicates that octet lattice beams exhibit superior performance to cube lattice beams. The octet lattice beam in the triple-layer double-column (TL-DC) arrangement absorbed 14.99 J of energy, representing a 38% increase compared to the 10.86 J absorbed by the cube lattice beam in the same design. The specific energy absorption (SEA) of the octet beam was measured at 0.39 J/g, which exceeds the 0.29 J/g recorded for the cube beam. Two distinct types of deformations were identified for the struts and the beam layers. Octet struts exhibit enhanced performance in stretch-dominated zones, whereas the cube system demonstrates superior efficacy in compressive-dominated regions. The results highlight the enhanced efficacy of octet lattice structures in energy absorption and mechanical stability maintenance. The investigation of sandwich lattice topologies integrating octet and cube structures indicates that while hybrid designs may exhibit efficiency, uniform octet structures yield superior performance. This study provides valuable insights into the structural design and optimization of lattice systems for applications requiring high-energy absorption and mechanical robustness. [ABSTRACT FROM AUTHOR]

The advancing development in biomaterials and biology has enabled the extension of 3D printing technology to the bioadditive manufacturing of degradable hard tissue substitutes. One of the key advantages of bioadditive manufacturing is that it has much smaller design limitations than conventional manufacturing and is therefore capable of producing implants with complex geometries. In this study, three distinct blends of polylactic acid (PLA) and polyhydroxybutyrate (PHB) were produced using Fused Deposition Modeling (FDM) technology. Two of these blends were plasticized with oligomeric lactic acid (OLA) at concentrations of 5 wt% and 10 wt%, while the third blend remained unplasticized. Each blend was fabricated in two structural modifications: solid and porous. The biodegradation behavior of the produced specimens was examined through an in vitro experiment using three different immersion solutions: saline solution, Hank's balanced salt solution (HBSS), and phosphate-buffered saline (PBS). All examined samples were also subjected to chemical analysis: atomic absorption spectroscopy (AAS), scanning electron microscopy (SEM), and energy-dispersive spectrometry (EDS). The results of the degradation experiments indicated a predominantly better absorption capacity of the samples with a porous structure compared to the full structure. At the same time, the blend containing a higher concentration of OLA exhibited enhanced pH stability over the evaluation period, maintaining relatively constant pH values before experiencing a minor decline at the end of the study. This observation indicates that the increased presence of the plasticizer may provide a buffering effect, effectively mitigating the acidification associated with material degradation. [ABSTRACT FROM AUTHOR]

This paper presents the process of manufacturing mechanical joint components using additive manufacturing (AM) techniques such as Material Extrusion (Fused Deposition Modelling (FDM)), Material Jetting (PolyJet), and Vat Photopolymerization (VAT)/Stereolithography (SLA). Using the PolyJet technique and a photopolymer resin, spline and threaded joint components were produced. For comparative analysis, the threaded joint was also fabricated using FDM and SLA techniques. PLA material was used for the FDM technique, while photopolymer resin was utilized for the SLA process. The components produced underwent a surface analysis to evaluate the accuracy of the dimensions in relation to the nominal dimensions. For the spline connection components, the dimensional deviations recorded by a 3D scanner ranged from −0.11 to +0.18 mm for the shaft and up to 0.24 mm for the sleeve. Measurements of screw and nut diameters showed the highest accuracy for screws produced using the PolyJet technique, while the nuts exhibited the best accuracy when fabricated with the SLA method. The profile of the screw threads using a contour gauge revealed the most accurate thread profile on the screw manufactured with the PolyJet technique. [ABSTRACT FROM AUTHOR]

This experimental study delves into the vibration response and energy absorption characteristics of three distinct auxetic tubular structures under quasi-static compression: the Reentrant, Double-V, and Anti-Trichiral designs. Notably characterized by their negative Poisson's ratio, these structures exhibit superior mechanical properties in comparison to conventional tubular structures with a positive Poisson's ratio. For consistency, all samples were standardized in terms of diameter and height, while variations due to unit cell geometry were parameterized based on the structure's weight. The samples were fabricated using Fused Deposition Modeling (FDM) with both PLA and PLA-Carbon filaments. Modal testing was conducted to evaluate structural damping, providing insights through time domain plots and frequency response functions. Subsequent compression testing facilitated the assessment of force-displacement relationships, thereby enabling the quantification of energy absorbed, specific energy absorption, and peak crushing force metrics. The analysis revealed that Reentrant unit cells constructed from PLA exhibited a 5% higher damping efficiency compared to Double-V and 4% higher than Anti-Trichiral units. Similarly, Reentrant units in PLA-Carbon demonstrated an 8 and 30% increase in damping relative to Double-V and Anti-Trichiral, respectively. During quasi-static compression, Double-V units in PLA showcased a 66 and 13% superior energy absorption capacity over Reentrant and Anti-Trichiral units, respectively. With PLA-Carbon, Double-V units exhibited a 28 and 116% enhanced energy absorption capacity compared to Reentrant and Anti-Trichiral units, respectively. This comprehensive evaluation offers insightful revelations into the damping and energy absorption capabilities of varying auxetic cell structures when composed of different materials, highlighting their potential in engineering applications. [ABSTRACT FROM AUTHOR]

One of the most critical components of a proton exchange membrane (PEM) fuel cell is the gas diffusion layer (GDL). Conventional preparation methods are complex, energy-consuming, and lack design flexibility. Additive manufacturing (AM) is widely used in various fields, with the fused deposition modeling (FDM) technique being the most widely used. With AM, GDLs can be designed and printed with precise control over their structure, porosity, and thickness. Previous research by the authors has shown high electrical resistance of the FDM-printed GDL. Thus, in this study, surface modification of printed GDL was performed to enhance its performance. The FDM-printed GDL with conductive graphite coating demonstrated a desirable breaking factor (2.11 kN/m) and air permeability (326 cm3/cm2/s). Its thickness, mass, and porosity were also determined to be appropriate and customizable. The performance of the manufactured GDL was examined in an open cathode air-breathing PEM fuel cell, indicating good feasibility at room temperature (20 °C). The results show that the application of the FDM technique in GDL manufacturing has great potential to revolutionize the fuel cell industry and drive progress toward a more sustainable future. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) enables the production of complex geometries that are not accessible by conventional processes. Fused deposition modeling (FDM) 3D printing is an important choice for many industries, particularly for additive manufacturing of microelectronic systems. The various physical properties of printing polymer materials, such as geometry, rheological behavior, and others, need to be taken into account in the printing process. In our study, a semi-crystalline polypropylene polymer PP is used in the FDM process, as it is characterized by deformability due to crystallization. We investigate the thermomechanical behavior of a semi-crystalline polymer PP (polypropylene) with different material deposition geometries ranging from a parallelepiped filament to a cylindrical filament in a numerical model developed. A coupling (to temperature vs. time evolution during printing) of solid mechanics, heat transfer, and crystallization kinetics equations was considered to build the Multiphysics numerical model capable of predicting temperature profiles, residual stresses, and degree of crystallization during the FDM process. The results obtained with the numerical model provide a reliable approach to predicting and adjusting the actual thermomechanical behavior of a printed electronics package. The values are calculated and compared to the six points in the two samples. The results show that the change in deposit shape resulted in a maximum deviation of 3.3 MPa for residual stress and 0.376 for the degree of crystallization, while a decrease was observed in the selected points with an average deviation of 1.81 MPa and 0.193 for residual stress and the degree of crystallization, respectively. This is due to the effects of the modification of the shape model on the temperature profile model, with the change in the 3D structures of the printed polymer material; the methodology presented in this paper allows the numerical model to be validated with an experimental study of the literature. The paper proposes future work and an experimental study to validate the results of the numerical model. [ABSTRACT FROM AUTHOR]

As a notable commercial aquaculture species, channel catfish (Ictalurus punctatus) in US faces challenges including the global market competition and enhanced feed costs. Since fish bone waste is a major source of calcium and hydroxyapatite, re-utilization gives birth to several advanced products in the development of animal feed, fertilizers, and nutrition supplements. Recent research findings introduce fish bone powder (FBP) reinforcement in Fused Deposition Modeling (FDM) of plastic composites. However, FBP so far has not been widely utilized for Direct Ink Writing (DIW) 3D printing of silicone composite. In this paper, catfish bone waste has been recycled and processed with a thermal procedure. FBP reinforced silicone composite structures have been developed and manufactured using low-viscosity DIW 3D printing. Morphological and chemical structures of FBPs were analyzed and compared before and after calcination. The rheological and mechanical characterization have indicated the potential of calcinated FBP in advancing the silicone composites. With 0%–50% weight percentages of FBP, composite samples can be designed to get any specified mechanical response (0.5–1.4 MPa in 50% tension strain and 150–550 N in 30% compression strain). The shape holding, overhang, and dimensional accuracy of FBP reinforced silicone composites in single (DIW) and dual (FDM + DIW) 3D printing processes have been demonstrated and summarized. With appropriate adjustments, this FBP-based 3D printing technology can be applied to byproduct recycling of all the US food-fish species, poultry, and livestock. [ABSTRACT FROM AUTHOR]

In this study, one of the most frequently used polymeric materials in fused deposition modeling (FDM) acrylonitrile butadiene styrene (ABS) is reinforced with different amount of carbon nanotubes (CNTs). Thermogravimetric analysis and differential scanning calorimetry analysis are applied to examine thermal degradation behavior of produced nanocomposite filaments. Specimens are manufactured by fused deposition modeling by using produced nanocomposite filaments. Tensile, creep and viscoelastic-viscoplastic behaviors of FDM-printed nanocomposite samples are investigated by conducting tensile, creep and loading–unloading tests under different strain rates and strain levels. Morphology of 3D printed samples is examined through scanning electron microscopy. Void densities which plays important role in mechanical behavior of additively manufactured samples are determined via ImageJ and CNT reinforcement on void densities are investigated. Data obtained from tests are used in system identification process, and multi-input–single-output model structures are proposed for the prediction of tensile, creep and recovery behaviors of 3D printed nanocomposite materials. [ABSTRACT FROM AUTHOR]

An important aspect to consider in the evaluation of parts and assemblies by X-ray computed tomography (XCT) is the attenuation coefficient of the different materials involved, which are directly related to their density; depending on this coefficient, the X-ray penetration varies and, therefore, varies the contrast between different materials and with the background. This becomes more critical in those assemblies in which materials are characterized by a high difference in density, where the lighter material could be difficult to be characterised. In this paper, the effect of the presence of metals in the dimensional evaluation of polymeric geometries (having lower density than the metal parts) is studied, to evaluate the errors caused in dimensional measurements of different geometries and surface texture characterization. Based on a common geometry, four scenarios have been experimentally tested with variations of metal amount, in which macro geometries (precision spheres made by different polymers) and micro geometries (inclined ramps manufactured by fused deposition modelling (FDM)) have been characterised. Results show errors in the surface determination of the polymeric features directly related to the presence of metal: a high amount of steel makes significantly difficult to accurately determine the interface between background and material due to the noise and artifacts created, while aluminium has less influence on the irregularities of the features extracted. This effect is more evident for polymers with lower density due to the higher difference. Numerically, most affected parameters are those sensible to variations in surface determination, such as spheres' form error and ramps' maximum surface texture (Sz), while more solid features as spheres' diameters, distances and ramps' average surface texture (Sa and Sq) remain more stable. In conclusion and to sum up, it has been found that the quantity of metal present in assemblies made of polymeric and metallic materials is correlated with distortions in the dimensional evaluation of polymeric features by XCT. [ABSTRACT FROM AUTHOR]

Lightweight and durable flexible materials with good mechanical properties, reliability, and excellent environmental compatibility have been increasingly widely applied in the field of wearable devices, microelectronics, and soft robots. An orthogonal experimental method was applied to fabricate thermoplastic polyurethane elastomer rubber (TPU) using fused deposition melting technology. The influence of three processing parameters on the mechanical property of the samples was investigated. The optimized printing parameters are 230 °C for the nozzle temperature, 0.1 mm for the thickness of the printing layer, and 100% for the filling percentage. The relationship between the fracture surface and the filling angle of the specimen under tensile stress was analyzed. To realize the lightweight of planar structural materials by melt deposition molding, nine types of planar porous structures were designed based on different average connectivity. The tensile stress simulation was carried out to obtain further the distribution of stress and the location of stress concentration. The relationship between relative density, fracture strength, and elongation at break was analyzed by static tensile test. The fracture morphology of the sample was observed and compared with the simulation results, which indicated that the hexagonal planar porous structure achieved the best balance between structural lightweight and mechanical properties. [ABSTRACT FROM AUTHOR]

This paper explores the potential use of fused deposition modeling (FDM) technology for manufacturing microwave and millimeter-wave dielectric resonator antennas (DRAs) for 5G and beyond communication systems. DRAs operating at microwave and millimeter-wave (mmWave) frequency bands were simulated, fabricated, and analyzed in terms of manufacturing quality and radio frequency (RF) performance. Samples were manufactured using a 3D printer and PREPERM® ABS1000 filament, which offers a stable dielectric constant ( ε r = 10 ± 0.35) and low losses (tan δ = 0.003) over wide frequency and temperature ranges. Surface profile tests and microscope measurements revealed discrepancies in the dimensions in the xy-plane and along the z-axis, consistent with the observed shift in resonant frequency. Despite these variations, reasonably good agreement between RF-simulated and measured results was achieved, and the DRA array successfully covered the intended mmWave band. However, challenges in achieving high precision may restrict applications at higher mmWave bands. Nevertheless, compared with conventional methods, FDM techniques offer a highly accessible and flexible solution with a wide range of materials for home and micro-manufacturing of mmWave DRAs for modern 5G systems. [ABSTRACT FROM AUTHOR]

Additive manufacturing of thermoplastic elastomers is challenging using fused deposition modeling due to their high melt viscosity, low column strength, and poor fusion among layers. Solvent‐cast 3D printing (SC‐3DP) is an efficient alternative to successfully 3D print such materials. However, selection of suitable 3D printing parameters is crucial to realize parts with optimum physicomechanical properties. In this work, statistical modeling and SC‐3DP parameter optimization for styrene–ethylene–butylene–styrene (SEBS) block copolymer were performed. The effect of 3D printing process parameters on shrinkage, relative density, and tensile strength was analyzed using response surface methodology. Experiments were planned as per central composite design and analysis of variance was performed to evaluate the significant parameters. SEBS content in the polymer solution significantly affected the shrinkage of SC‐3DP samples. Moreover, relative density and tensile strength were significantly affected by print speed and layer height. A significant interaction between print speed and layer height was also noticed for tensile strength and relative density of printed samples. Multi‐objective optimization using genetic algorithm was also performed to minimize shrinkage and maximize relative density and tensile strength. Finally, a case study was conducted comparing the physicomechanical properties of SC‐3DP samples printed at optimized process parameters and compression molded samples. Highlights: Statistical models were developed using response surface methodology.Genetic algorithm based multi‐objective optimization was performed.Optimum solvent‐cast 3D printing (SC‐3DP) process parameters were determined. [ABSTRACT FROM AUTHOR]

Due to its biodegradability, biocompatibility, and mechanical properties, poly‐lactic acid (PLA) is a leading biomaterial for numerous applications, especially for fused deposition modeling and fused filament fabrication. Nonetheless, the absence of a comprehensive recycling strategy may emerge as a significant source of plastic pollution in the future. Indeed, the polymer undergoes deterioration during melt recycling, resulting in a decrease in some mechanical properties that can compromise recyclability. To improve the properties of recycled PLA, the utilization of organic fillers coming from renewable materials can be considered as a sustainable solution. The objective of this work is then to evaluate the effect of recycling (reprocessing) on a virgin raw material as well as on biocomposites based on spent coffee grounds (incorporating 5% of spend coffee grounds in weight). The different types of filaments are extruded and re‐extruded and characterized under tensile, melt flow index, and hardness tests. The results show that the increase in the number of extrusions whether for virgin PLA or the composite contributes to the diameter fluctuation. Regarding the tensile properties, the rise in the frequency of recycling shows a weakness in the tensile strength and the elongation at break. On the other hand, Young's modulus values exhibit fluctuations. Concerning the addition of the spent coffee grounds filler, no major enhancement is observed in the tensile strength and the elongation at break, which is attributed to the poor adhesion between the matrix and the filler. The recycling process affects the hardness values of PLA, leading to an increase in these values, as well as those of the composite, which can be associated with the increased crystallinity caused by the recycling process and the SCG incorporation. Highlights: Recycling and reusability strategy for poly‐lactic acid (PLA) and PLA/spent coffee grounds (SCG) filaments.Assessment of recycling effects on PLA and PLA/SCG.Mechanical characterization through tensile and hardness testing. [ABSTRACT FROM AUTHOR]

Braille is a universal tactile writing system for the blind and visually impaired. Braille can be printed in several ways, including embossing, screen, or UV ink-jet printing. In this study, we propose to use three-dimensional, 3D, printing technology to print dots of the Braille alphabet. The 3D model was designed with CAD software and then overprinted with Fused Deposition Modelling, FDM, technology with polylactide filament. Then, the quality of braille dots was assessed according to the standard for Braille. The estimated height (0.5 mm) and diameter (1.3 mm) for Braille dot were not achieved for the designed model. The measured values of the Braille dots were 0.38 ± 0.03 mm and 1.0 ± 0.07 mm for the height and diameter, respectively. The dot quality was assessed with an optical microscope. The distribution and location of the Braille can be acceptable, but the reproduction of dot shape, curvature, and dimensions is not compatible with the standard for Braille dots. Despite that, Braille is readable, and FDM can be a cheap solution to develop customized and unique plates with Braille imitating conventional Braille dots embossed in cardboard. [ABSTRACT FROM AUTHOR]

This study delves into the manufacturing strategies employed for fabricating tensile samples utilized in the mechanical characterization of material extrusion (MEX) components constructed with polyaryletherketone (PAEK) for aerospace applications. Two distinct methods were investigated for obtaining tensile test samples: direct cutting and extraction from a box. These methods were examined under both as-printed and annealing conditions. Quasistatic tensile tests were conducted along the building direction to evaluate the impact of processing conditions on the adhesion of overlying layers. The results unveiled significant disparities in mechanical behavior and crystallinity between directly printed samples and those derived from the box. The Young's modulus exhibited marginal influence; however, the tensile strength of directly printed samples measured at 30 MPa (prior to annealing), corresponding to 50% of the strength observed in samples cut from the box (60 MPa). Moreover, the elongation at rupture of directly printed samples was found to be less than 2%, while that of cut samples exceeded 8%. Notably, directly printed samples exhibited a significant degree of incipient crystallization (12.18%), contrasting with the lower level of crystallinity observed in samples cut from the box (3.27%). These findings underscore the importance of recognizing the limitations associated with direct sample printing, emphasizing its crucial role in accurately characterizing components destined for the aerospace industry. Furthermore, this understanding is pivotal for optimizing the performance and reliability of MEX-printed PAEK components in aerospace engineering applications. [ABSTRACT FROM AUTHOR]

Fused filament fabrication (FFF), a known variation of fused deposition modeling (FDM), is a fast-growing additive manufacturing technique that is widely used in various industrial and technological applications owing to its ability to build functional parts with complex geometrical features in a reasonably good time. FFF utilizes a variety of thermoplastic materials such as polylactic acid (PLA), acrylonitrile butadiene styrene (ABS), nylon (polyamide), and polycarbonate (PC) each offering distinct properties suitable for different applications. Polycarbonate is a high-performance polymer with engineering applications, but it is a less studied material with respect to the FFF process. The mechanical properties and dimensional accuracy of FFF-built parts are influenced by several process parameters, and choosing the best set of process parameters is essential for achieving the desired properties in the built parts. This study examined the effects of four critical process parameters (layer thickness, extrusion temperature, printing speed, and extrusion width) on the mechanical properties such as the tensile, flexural, and compression strengths of FFF-printed polycarbonate specimens. Tensile, flexural, and compressive tests were performed according to ASTM standards. Mathematical models based on dimensional analysis were developed to determine the correlation between the process parameters and mechanical properties of the printed specimen. The predicted models obtained showed a good correlation with the measured values and could be used to generalize the prediction for the process conditions of the FFF process. Validation tests were conducted to verify the developed mathematical models. The developed mathematical models provide a tool for optimizing the manufacturing parameters during the fused filament fabrication process. [ABSTRACT FROM AUTHOR]

BACKGROUND: Currently, the verification of the precision of personalized bone models is usually performed by methods such as paired t-tests or intraclass correlation coefficient, but such methods often require the production of large batches of models, which do not satisfy the need for immediate use of personalized models. OBJECTIVE: To study the feasibility of establishing the equivalent model to verify the precision of the personalized bone model rapidly. METHODS: Bone CT images of three adults were randomly obtained for reconstruction. 3D printing was used to create personalized bone models, and then the personalized bone models were scanned using CT and reconstructed. Mimics was used to compare the reconstructed models of bone CT images with the bone CT images. Geomagic Studio was used to analyze the fitting deviation between the reconstruction model of personalized bone model CT image and the reconstruction model of skeletal CT image. The 3D-printed personalized bone model was measured against the measurement positions and dimensions marked on the reconstruction model of skeletal CT image, and the error was calculated. RESULTS AND CONCLUSION: (1) By comparing the reconstructed bone CT image model with the bone CT scan image, the two were compatible in terms of anatomical structure and morphology, and the contours almost overlapped. (2) By fitting bias analysis, the standard bias was 0.176, 0.226, and 0.143 mm in order, and all the results were < 0.25 mm. (3) By measuring and calculating the model, the mean relative errors were 0.44%, 0.21%, and 0.13%, and all the results were within 5% error. (4) The constructed equivalent model was in line with the basic conditions for making personalized bone models. The established equivalent model met the clinical needs and design requirements, and it was feasible to use the method of the equivalent model to verify the precision of the personalized bone model quickly. (5) This method could provide a targeted and rapid way to verify the precision of personalized bone models. It could achieve the goal of providing immediate clinical use without the need to produce large batches of models compared to conventional methods such as paired t-tests or intraclass correlation coefficient. [ABSTRACT FROM AUTHOR]

This study aims to explore and select a sample of three-dimensional (3D) printed lattice structures suitable for fabrication of a lumbar brace. In particular, the study compared honeycomb, gyroid, and X-shape lattice structures. Thirty-six samples with two thicknesses, two pattern repeats, three lattice structures, and three 3D printing manufacturing methods and material variables were fabricated to evaluate tensile strength, flexural strength, weight, and density. Mechanical evaluation revealed that the tensile and flexural strengths of the honeycomb structure were higher than those of other structures. In addition, the fused deposition modeling (FDM) method using thermoplastic polyurethane (TPU) material had higher tensile and flexural strengths compared with the other two printing methods and materials. The honeycomb structure weighed the most, followed by the X-shape and gyroid structures. The sample made of PolyJet method with Agilus material showed higher values of weight and density than the other samples. Based on the experimental results, it is considered that TPU material, FDM, and selective laser sintering printing methods are suitable for production of the lumbar support brace because it is flexible and allows body movement but has moderate strength and density. By adjusting the pattern repeat and thickness of the lattice structure variable, we can determine the structure that is most suitable for lumbar support. Considering the lightweight requirements of lumbar support, future studies should devise ways to improve the lightweight properties of samples. [ABSTRACT FROM AUTHOR]

Each year, a significant amount of waste is produced from carbon fiber polymer composites at the end of its lifecycle due to extensive use across various applications. Utilizing regenerative carbon fiber as a feedstock material offers a promising and sustainable approach to additive manufacturing based on materials. This study proposes the additive manufacturing of recycled carbon fiber with a polyamide-12 polymer composite. Filaments of recycled carbon fiber-reinforced polyamide-12 (rCF-PA12) with different recycled carbon fiber contents (0%, 10%, and 15% by weight) in the polyamide-12 matrix are developed. These filaments are utilized for 3D printing of specimens by using various infill density parameters (80% and 100%) on a fused deposition modeling 3D printer. The study examined how the fiber content and infill densities influenced the flexural performance of the printed specimens. Notably, the part containing 15 wt % recycled carbon fiber (rCF) composites showed a significant improvement in flexural performance due to enhanced interface bonding and effective fiber alignment. The results indicated that reinforcing the printed part with 10% and 15 wt% recycled carbon fiber (rCF) improved the flexural properties by 49.86% and 91.75%, respectively, compared to the unreinforced printed part under the same infill density and printing parameters. The investigation demonstrates that the additive manufacturing-based technique presents a potential approach to use carbon fiber-reinforced polymers waste and manufacture high-performance engineering, economic, and environmentally friendly industrial applications with the complicated design using different polymer matrices. [ABSTRACT FROM AUTHOR]

The study examined the degradation process of various types of polymers used to form models using the fused deposition modeling (FDM) and three-dimensional printing (3DP) methods and used in the investment casting method. Commercial filaments made of polylactide (PLA), acrylonitrile butadiene styrene terpolymer (ABS), high-impact polystyrene (HIPS), polyamide 12 (PA12), poly(methyl methacrylate) (PMMA), and polypropylene (PP) were used to produce gypsum molds. The assessment included organic volatile compounds (VOCs) released during mold heating and model degradation, which is characteristic of this technological process. The screening qualitative chromatographic analysis of decomposition products sampled from various points of the production hall made it possible to define potential threats related to the processing of selected polymers and the necessary preventive measures. Furthermore, passive diffusion-type samplers were used at the sampling stage of VOCs emitted to the gaseous phase to reduce nuisance and user interference. Studies have been completed to characterize the thermoplastic polymer degradation process. The coupled thermogravimetry (TGA) with analysis of gaseous products by infrared spectroscopy with Fourier transformation (FT-IR) has been used. The presented results are the first to compare and rate the use of this still-developing novel aspect of castings by the method of fused models. [ABSTRACT FROM AUTHOR]

Highlights Additive manufacturing for polylactic acid (PLA) reinforced with cellulose nanofibrils (CNF) could unlock fabrication of specialized and user‐specific biomedical devices. However, the process of combining PLA and CNF is challenging and proves complicated with possible irreversible CNF agglomeration and organic solvents leftover, particularly when involving solvent‐casting technique. Direct melt‐blending can mitigate these issues, but there are few reports of a single‐step melting and extrusion process to produce ready‐to‐use 3D printing filaments. This study compares the distribution of CNF fillers within the PLA matrix in PLA/CNF composites made by direct melt‐blending into filaments using a benchtop filament maker, and by solvent‐casting followed by extrusion into filaments. The filaments were 3D‐printed via fused deposition modeling (FDM), followed by tensile testing, morphology, and other characterizations. Uneven filament diameters were observed for the composite filaments prepared via solvent‐casting because of severe agglomeration, resulted in poor printability and tensile properties of filaments and 3D‐printed samples. Direct melt‐blended filament diameters were consistent, resulted in only slight decrease of tensile properties compared to pure PLA, contributing to the highest maximum tensile strength of 3D‐printed sample of 51.47 ± 1.73 MPa at 5% CNF loading. Morphology revealed good integration of CNF into PLA matrix starting at 3% CNF loading. Direct melt‐blending was comparable to the conventional methods, which enables simpler PLA/CNF composite preparation especially for 3D printing. Better dispersibility achieved by direct melt‐blending than by solvent‐casting. PLA/CNF filaments produced via solvent‐casting suffered severe agglomeration. Direct melt‐blended PLA/CNF5% yielded the highest maximum tensile strength. Morphology reveals good CNF‐PLA integration starting at 3% of CNF loading. Worsened agglomeration causing increased number of voids observed at 10% CNF. [ABSTRACT FROM AUTHOR]

This study presents a novel approach to the development of high-performance supercapacitors through 3D printing technology. We synthesized a composite material consisting of silver-doped reduced graphene oxide (rGO) and dodecylbenzenesulfonic acid (DBSA)-doped polyaniline (PANI), which was further blended with polylactic acid (PLA) for additive manufacturing. The composite was extruded into filaments and printed into circular disc electrodes using fused deposition modeling (FDM). These electrodes were assembled into symmetric supercapacitor devices with a solid-state electrolyte. Electrochemical characterization, including cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) tests, demonstrated considerable mass-specific capacitance values of 136.2 F/g and 133 F/g at 20 mV/s and 1 A/g, respectively. The devices showed excellent stability, retaining 91% of their initial capacitance after 5000 cycles. The incorporation of silver nanoparticles enhanced the conductivity of rGO, while PANI-DBSA improved electrochemical stability and performance. This study highlights the potential of combining advanced materials with 3D printing to optimize energy storage devices, offering a significant advancement over traditional manufacturing methods. [ABSTRACT FROM AUTHOR]

This study investigates the differences in mechanical properties between acrylonitrile butadiene styrene (ABS) samples produced using fused deposition modeling (FDM) and stereolithography (SLA) using ABS filaments and ABS-like resin, respectively. The central question is to determine how these distinct printing techniques affect the properties of ABS and ABS-like resin and which method delivers superior performance for specific applications, particularly in dental treatments. The evaluation methods used in this study included Shore D hardness, accelerated aging, tensile testing, Izod impact testing, flexural resistance measured by a 3-point bending test, and compression testing. Poisson's ratio was also assessed, along with microstructure characterization, density measurement, confocal microscopy, dilatometry, wettability, Fourier-transform infrared spectroscopy (FTIR), and nanoindentation. It was concluded that ABS has the same hardness in both manufacturing methods; however, the FDM process results in significantly superior mechanical properties compared to SLA. Microscopy demonstrates a more accurate sample geometry when fabricated with SLA. It is also concluded that printable ABS is suitable for applications in dentistry to fabricate models and surgical guides using the SLA and FDM methods, as well as facial protectors for sports using the FDM method. [ABSTRACT FROM AUTHOR]

A novel approach, i.e., Continuous Material Deposition on Filaments (CMDF), for the incorporation of active materials within 3D-printed structures is presented. It is based on passing a filament through a solution in which the active material is dissolved together with the polymer from which the filament is made. This enables the fabrication of a variety of functional 3D-printed objects by fused deposition modeling (FDM) using commercial filaments without post-treatment processes. This generic approach has been demonstrated in objects using three different types of materials, Rhodamine B, ZnO nanoparticles (NPs), and Ciprofloxacin (Cip). The functionality of these objects is demonstrated through strong antibacterial activity in ZnO NPs and the controlled release of the antibiotic Cip. CMDF does not alter the mechanical properties of FDM-printed structures, can be applied with any type of FDM printer, and is, therefore, expected to have applications in a wide variety of fields. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This study focuses on the development of environmentally sustainable polypropylene (PP)-based composites with the potential for biodegradability by incorporating cellulose and the oligomeric siloxane ES-40. Targeting industrial applications such as fused deposition modeling (FDM) 3D printing, ES-40 was employed as a precursor for the in situ formation of silica particles via hydrolytic polycondensation (HPC). Two HPC approaches were investigated: a preliminary reaction in a mixture of cellulose, ethanol, and water, and a direct reaction within the molten PP matrix. The composites were thoroughly characterized using rotational rheometry, optical microscopy, differential scanning calorimetry, and dynamic mechanical analysis. Both methods resulted in composites with markedly reduced crystallinity and shrinkage compared to neat PP, with the lowest shrinkage observed in blends prepared directly in the extruder. The inclusion of cellulose not only enhances the environmental profile of these composites but also paves the way for the development of PP materials with improved biodegradability, highlighting the potential of this technique for fabricating more amorphous composites from crystalline or semi-crystalline polymers for enhancing the quality and dimensional stability of FDM-printed materials. [ABSTRACT FROM AUTHOR]

In terahertz (THz) optical systems, polymer-based manufacturing processes are employed to ensure product quality and the material performance necessary for proper system maintenance. Therefore, the precise manufacturing of system components, such as optical elements, is crucial for the optimal functioning of the systems. In this study, the authors investigated the impact of various 3D printing parameters using fused deposition modeling (FDM) on the optical properties of manufactured structures within the THz radiation range. The measurements were conducted on 3D printed samples using highly transparent and biocompatible cyclic olefin copolymer (COC), which may find applications in THz passive optics for "in vivo" measurements. The results of this study indicate that certain printing parameters significantly affect the optical behavior of the fabricated structures. The improperly configured printing parameters result in the worsening of THz optical properties. This is proved through a significant change in the refractive index value and undesirable increase in the absorption coefficient value. Furthermore, such misconfigurations may lead to the occurrence of defects within the printed structures. Finally, the recommended printing parameters, which improve the optical performance of the manufactured structures are presented. [ABSTRACT FROM AUTHOR]

This study explores the optimization of fused deposition modeling (FDM), a prominent 3D printing technology known for its accessibility and cost-effectiveness. The research aimed to identify and reduce errors associated with key printing parameters, specifically the layer height, printing temperature, and printing speed. Advanced tools such as a Keyence laser scanner and microscope were used to evaluate the dimensional accuracy and surface quality of various samples. The results indicate that the optimal settings for the layer height (0.16 mm), printing temperature (250 °C), and printing speed (350 mm/s) significantly minimize variation, resulting in more consistent and accurate prints. The results also showed that the samples printed with these optimized parameters had the lowest variability, underscoring the critical importance of precisely managing these factors. The findings highlight the critical role of fine-tuned FDM parameters in improving the quality and reliability of printed objects and provide valuable insights for further advances in 3D printing processes. [ABSTRACT FROM AUTHOR]

The technology of additive manufacturing has advantages for prototyping. In certain instances, it may be preferable to use 3D-printed components as the primary component making it essential for these components to have sufficient mechanical properties. Therefore, the effect of ambient conditions on the mechanical properties of these components can be quite significant. In this study, the effect of different ambient conditions on the mechanical properties of 3D-printed PLA parts was investigated. Three specific conditions were considered for this purpose: hot-dry air, hot water, and cold-dry air. Standard samples were fabricated using a 3D-printer and then subjected to the aforementioned environments for 30-min before being tested with a universal testing device. The yield strength, maximum strength, elastic modulus, and toughness values were obtained from the resulting stress–strain graphs of the printed components. The study revealed that ambient conditions significantly affect the mechanical strength of PLA components. Notably, the components retained their tensile strength in cold and dry environments, whereas their mechanical properties deteriorated under wet conditions. Additionally, cold conditions appeared to enhance the mechanical properties of the printed components. In conclusion, it was determined that variable ambient conditions can either degrade or improve the mechanical properties of PLA-printed components. [ABSTRACT FROM AUTHOR]

Highlights Considering the types of carbon fiber reinforced polymer (CFRP) waste and the length of recycled carbon fiber (rCF), it is still a challenge to obtain high‐performance rCF and realize its high‐value reuse. In this paper, rCF was obtained by the thermal activated oxide semiconductor, and the effects of temperature and time on the resin decomposition rate of CFRP with different resin systems were analyzed. Three remanufacturing processes, namely wet fiber alignment (WFA), direct ink writing (DIW) and fused deposition modeling (FDM), were used to remanufacture rCF in millimeter and micron scale into recycled carbon fiber reinforced polymer (rCFRP) and the effects of rCF content on the mechanical properties of rCFRP were studied. The results showed that the optimal recycling parameter for EP‐EDA is 520°C, 45 min, and for EP‐MeTHPA and phenolic resin, the optimal recycling parameter is 520°C, 35 min. With the increase of rCF content, the tensile strength and modulus of WFA, DIW and FDM samples all increased to varying degrees. When the rCF content is 15 wt%, the tensile strength of WFA, DIW and FDM samples is increased by 355.6%, 68.4%, and 34.5%, respectively, compared with the corresponding pure resin samples. The mechanical properties of WFA, DIW and FDM samples are greatly different due to the rCF content, rCF length, interface bonding and alignment of rCF. This paper emphasizes the important effects of remanufacturing process, material composition and rCF content on the properties of rCFRP, and provides multiple ways for high‐value reuse of rCF. rCF obtained by thermal activated oxide semiconductor. Resin decomposition rate of CFRP waste with different resin systems. Multiple remanufacturing processes for rCF. Effects of rCF content and material composition on the properties of rCFRP. [ABSTRACT FROM AUTHOR]

Highlights The increasing awareness in environmental safety has led to rapid development in production of electricity using wind energy with wind turbines. The widespread deployment of wind turbines has outpaced the effective recycling of End‐of‐Life wind turbines. This study explores the potential of mechanically recycling decommissioned wind turbine blades (WTB) as reinforcement material in 3D printing processes. Utilizing mechanical grinding, materials were extracted from the waste blades and subsequently analyzed using Fourier transform infrared spectroscopy, Differential scanning calorimetry, and thermogravimetric analysis to determine optimal processing conditions. The reclaimed materials were then blended with recycled polypropylene through single‐screw extrusion to fabricate tensile test samples via Fused Deposition Modeling. The impact of print orientation on mechanical strength was examined at 0°, 45°, and 90° angles. Morphological analysis was conducted on the fractured specimens to assess the failure characteristics. The findings indicate that samples printed at a 90° orientation exhibited superior mechanical properties, suggesting a viable pathway for incorporating wind turbine waste into sustainable manufacturing cycles. A decentralized‐mechanical recycling technique to the waste WTB. The necessary material parameters for the operations employed in this study. Reinforced 3D printable filaments from waste WTB. Stronger reinforced filaments obtained from proper fiber alignment. [ABSTRACT FROM AUTHOR]

This study investigates the additive manufacturing (AM) process of 30% ceramic‐reinforced composite PLA material using the fused deposition modeling (FDM) technique. The effects of various printing parameters on tensile strength, build time, and material consumption are comprehensively analyzed through a combination of the Taguchi method, analysis of variance (ANOVA), and gray relational analysis (GRA). Experimental design parameters include nozzle diameter, infill density, infill pattern, wall line count, print speed, and layer height. Statistical analyses reveal significant contributions of these parameters to mechanical properties and production efficiency. Single and multi‐objective optimizations of the responses were performed. The single optimization resulted in a significant increase in tensile strength from 39.9 to 48.10 MPa. Production time was reduced from 16 to 9 min; material consumption decreased from 4.95 to 2.43 g for tensile test specimens. The use of GRA in multi‐objective optimization has led to a significant improvement of 8.31% in the gray relational grade (GRG) when compared to the initial parameter settings. These findings provide valuable insights for optimizing FDM processes in the fabrication of composite PLA materials. This contributes towards the advancement of additive manufacturing technology and its applications across various industries. and its applications across various industries. Highlights: Tensile strength increased while reducing build time and material consumption.Optimal printing parameters were identified for a composite PLA material.Layer height and nozzle diameter were effective parameters. [ABSTRACT FROM AUTHOR]

Fused deposition modeling (FDM) process with laser assistance can effectively enhance the interfacial strength of short carbon fiber/poly‐ether‐ether‐ketone (SCF/PEEK) composites. However, excessive crystallization of the semi‐crystalline matrix generally results in irregular shrinkage, which seriously deteriorates dimensional accuracy of composite specimens. To overcome this issue, we establish a novel heat treatment technique by the combinations of laser assistance and post‐treatment to improve the interlayer properties and dimensional accuracy simultaneously. It is found that lateral cracks at the interlayer interfaces can be completely eliminated at laser pre‐heating temperature Tx=210°C, due to the reduction of temperature gradient and residual stresses. The further increased Tx evidently promotes molecular diffusion and crystallization behaviors, thus increasing the interlaminar shear strength of FDM‐printed specimens. The post‐treatment temperature Tp visibly promotes mutual diffusions of the molecules and formations of the perfect crystals, strengthening the interlayer adhesion of specimens. The proposed combination technique can increase the interlayer strengths of composite specimens by approximately 22.5%, while their warpage deformations are suppressed simultaneously. Highlights: Pre‐heated temperature 210°C was a threshold for eliminating lateral cracks at interlayer interfaces.Post‐treatment significantly promoted molecular diffusion and crystallization behaviors.A novel technique was established to improve interlayer strength while suppressing warpage.The combination technique could increase the interlayer shear strength by approximately 22.5%. [ABSTRACT FROM AUTHOR]

Study Design: A fused deposition modeling three-dimensional (3D)-printed model of the L4–5 vertebra for lumbar discectomy was designed. The model included separately printed dura mater, spinal cord, ligamentum flavum, intervertebral disc (from thermoplastic polyurethane), and bony structures (from polylactic acid), and the material cost approximately US$ 1 per model. A simple plumbing endoscope was used for visualization. Dura mater injury was assessed by painting two layers on the dura mater, which peeled off with trauma. Purpose: Endoscopic spine surgery is a subject of high interest in neurosurgery given its minimally invasive nature; however, it has a steep learning curve. This study evaluated the effectiveness of a cost-efficient 3D-printed model when teaching this technique to neurosurgery residents. Overview of Literature: Only a few studies have investigated the efficacy of such a model. Methods: Eight residents with >2 years of training participated. Residents performed the procedure bilaterally and twice at 1-week intervals. Results: From the 32 surgeries, four were excluded because of facet removal (as it widened the surgical corridor), leaving 28 surgeries for analysis. Initial surgeries demonstrated a mean operation time of 21 minutes 18 seconds (standard deviation [SD], 2 minutes 32 seconds), which improved to a mean of 6 minutes 45 seconds (SD, 37 seconds) in the fourth surgery (F(3, 17)=19.18, p<0.0001), demonstrating a significant reduction in surgical time over successive surgeries. The median area with the paint removed decreased, from 161.80 (85.55–217.83) to 95.13 mm2 (12.62–160.54), (F(2.072, Inf)=2.04, p=0.128); however, this was not significant. Resident feedback indicated high satisfaction with the educational value of the model. Conclusions: The developed fully 3D-printed model provides a viable and scalable option for neurosurgical training programs, enhancing the learning experience while maintaining low costs. This model may be an excellent stepping stone for learning lumbar spine endoscopy, acclimating to the two-dimensional view, progressing to cadaver models, and, eventually, independent surgery. [ABSTRACT FROM AUTHOR]

Background/Objectives: The pharmacy profession has undergone significant changes driven by advancements in patient care and healthcare systems. The FDA approval of Spritam® (levetiracetam), the first 3D-printed drug, has sparked increased interest in the use of Fused Deposition Modeling (FDM) 3D printing for pharmaceutical applications, particularly in the production of polypills. Methods: This review provides an overview of FDM 3D printing in the development of pharmaceutical dosage forms, focusing on its operation, printing parameters, materials, additives, advantages, and limitations. Key aspects, such as the ability to personalize medication and the challenges associated with the technique, including drug stability at high temperatures, are discussed. Results: Fourteen studies relevant to FDM 3D-printed polypills were analyzed from an initial pool of 60. The increasing number of publications highlights the growing global interest in this technology, with the UK contributing the highest number of studies. Conclusions: FDM 3D printing offers significant potential for personalized medicine by enabling precise control over dosage forms and tailoring treatments to individual patient needs. However, limitations such as high printing temperatures and the lack of standardized GMP guidelines for large-scale production must be addressed to fully realize its potential in pharmaceutical manufacturing. [ABSTRACT FROM AUTHOR]

The aim of this study is to determine experimentally the higher material parameter g$g$ of a metamaterial with a triangular substructure and to verify a higher‐gradient elasticity model for beams with internal substructures or microstructures. The investigations of the higher‐gradient elasticity models of Bernoulli‐Euler and Timoshenko beams with a periodic triangular substructure in Khakalo et al. show that the bending stiffness strongly depends on the geometrical parameters of the lattice structure. To achieve this goal, beams with triangular substructures were additively manufactured using fused deposition modeling and stereolithography. They were experimentally investigated in tensile and bending tests. Three different types of beams with triangular substructures were produced, consisting of one, two and four layers of triangular beams, using two different materials: Polylactide and epoxy resin. The higher material parameter g was quantitatively determined based on the experimental results using inverse analysis. The results are valid for these specific variations of the substructure and can adequately represent the elastic size effects. In addition, this study investigates the relationship between the bending stiffness and the geometric parameters of the lattice structure as well as the influence of the curing time on the elastic properties of epoxy resin. The experiments involved testing the triangular beams under tensile and bending loads. The numerical and experimental results were compared using digital image correlation. Based on the experimental data, a higher gradient material parameter representing the geometric structure of the lattice was determined. [ABSTRACT FROM AUTHOR]