Струйная 3D-печать керамического интерконнектора на основе Zr0.9Y0.1O1.95 для микротрубчатых твердооксидных топливных элементов

Three-dimensional (3D) cementitious material printing (3DCMP), which produces structures layer by layer without collapse, is gaining popularity due to its various merits such as fabricating complex and highly customised structures, significantly labour-savings, and increasing worker safety. Numerous investigations have been conducted on developing new materials for 3DCMP and examining the impacts of the printing process on filament quality experimentally. However, the 3D cementitious materials have not been tailored in a systematic method, and the material flow behaviour has not been studied thoroughly under various conditions. Hence, this thesis deals with the following four topics: (1) Material multi-objective optimisation based on material rheological properties (dynamic yield stress, plastic viscosity); (2) Modelling of material flow behaviour during the extrusion and deposition process, and investigating the combined effects of material rheological properties and printing process parameters on filament deformation for straight-line printing; (3) Developing numerical models to investigate material flow behaviour by considering the combined effects of material rheological properties and printing process parameters at corners; (4) Identifying printing process windows based on filament cross-section ratio and developing a novel nozzle configuration to improve filament homogeneity at corners. Firstly, the Mixture Design Approach is adopted in this thesis to formulate the correlation between the cementitious material components and material rheological properties (such as static yield stress and dynamic yield stress), and then identify the optimal components for 3DCMP. Additionally, the content of each component is extended to a wider range rather than a specific point by using the Desirability function. Finally, the Mixture Design Approach is proven to be an effective method of optimising the cementitious materials used in 3DCMP applications. Secondly, a numerical model is developed to investigate the material flow behaviour during the extrusion and deposition process in straight-line printing. Additionally, a Support Vector Machine (SVM) approach is proposed to investigate the combined effects of material rheological properties and printing process parameters on deformation of the printed filament. The SVM model results show that the deformation of the printed filament is independent of plastic viscosity, whereas material yield stress and relative nozzle travel speed significantly affect the deformation of the printed filament. Thereafter, an empirical parametric associative model is proposed to predict the filament deformation based on material yield stress and relative nozzle travel speed. Finally, the numerical model is extended to study the formation of voids within printed multi-layer structures. The results show that products porosity decreases with relative nozzle travel speed ζ for both the circular nozzle and rectangular nozzle. The rectangular nozzle performs better in reducing product porosity. Thirdly, tearing or skewing may occur at the filament surface due to uneven mass distribution of the filament produced with a rotational rectangular nozzle at corner. To remove the undesired phenomenon, the one-dimensional (1D) and three-dimensional (3D) models are developed to study the flow behaviour during the extrusion and deposition process, and hence the filament mass distribution at corners. Both the 1D and 3D models give reasonable predictions as the tool path radius R is larger than 60 mm. However, only the 3D model gives better prediction as the tool path radius is smaller than 60 mm. The 3D numerical results show that material flows in three dimensional domains and some material spills from the overfilled zone during the deposition process. Additionally, the results indicate that the rheological properties have little effect on the cross-section ratio, while the printing process parameters affect filament cross-section ratio significantly. A higher relative nozzle travel speed, larger tool path radius, and lower nozzle aspect ratio are promising routes in obtaining a uniform material distribution of the filament. Since the material flow behaviour at corners is sensitive to printing process parameters, it is necessary for the printing process windows to be identified to ensure homogeneous filament mass distribution and good mechanical properties of the printed filament at corners. The support vector machine (SVM) method is used to predict the acceptable printing process window, and the prediction accuracy is improved with the transfer learning method. The experimental results show the feasibility and effectiveness of the machine learning methods in printing process windows determination under various conditions. Generally, the machine learning method (data-driven method) provides more systematic, reliable, and efficient results than the conventional variable control method in printing process windows determination. However, a homogeneity of the filament still cannot be achieved by changing printing process parameters, hence, a novel nozzle configuration (the Gaussian shape) is proposed to address the issue due to its various merits: (a) low-pressure loss, (b) curved nozzle wall, (c) adjustable aspect ratio. The experimental results show that the Gaussian shape performs better in improving the filament homogeneity as compared to rectangular nozzle and trapezoidal nozzle at corners under small tool path radius (R ≤ 30).

Recently, three-dimensional (3D) printing has garnered tremendous amounts of attention in various applications. In this study, we suggest a facile means of creating 3D-printed foldable electrodes on paper via the direct printing of composite pastes consisting of conductive fillers and a thermoplastic elastomer. The 3D-printability of the prepared composite pastes is investigated depending on the rheological properties. It is revealed that the composite paste with a high storage modulus would enable the formation of highly conductive features with a resistance of 0.4 Ω cm−1 on three-dimensional paper structures. The mechanical bending/folding stability levels of the printed electrodes are evaluated to judge the possibility of realizing 3D-printed origami electronics. The resistance is changed slightly with a normalized resistance value of 2.3, when the printed electrodes are folded with a folding angle of 150°. It is demonstrated that the 3D-printed composite electrodes are applicable to various origami electronics, including electrical circuits, strain sensors and electrochemical sensors.

One of the major advantages of 3D food printing is the customizability in terms of structure, design, and nutritional content. However, printability of the ingredients and the quality of the 3D printed food products are dependent on several product and printing parameters. In this study, nutrient dense cookies were developed with underutilized ingredients including jackfruit seed powder and finger millet powder as base materials using 3D food printing. The hardness, rheological behavior, and microstructure of 3D printed cookies with different products (e.g., water butter ratio) and printing (e.g., fill density and temperature) parameters were analyzed. The 3D printed cookies were developed by extruding at 27 and 30 °C with fill density values of 50%, 70%, 90%, and 100% and water butter ratios of 3:10 and 6:5. The 3D-printed cookie dough exhibited a more elastic behavior with higher storage modulus values than the loss modulus. The hardness of the baked cookies was influenced by printing temperature, fill density, and water butter ratio of 3D printed cookie dough and their interactions. The closed porosity of 3D printed cookies increased while the open porosity decreased with an increase in fill density. The baking times required were longer for 3D-printed cookies with higher fill density values. Overall, this study shows the importance of considering the specific ingredient and printing parameters to develop high quality 3D-printed cookies.

PurposeThe purpose of this study, most recent advancements in threedimensional (3D) printing have focused on the fabrication of components. It is typical to use different print settings, such as raster angle, infill and orientation to improve the 3D component qualities while fabricating the sample using a 3D printer. However, the influence of these factors on the characteristics of the 3D parts has not been well explored. Owing to the effect of the different print parameters in fused deposition modeling (FDM) technology, it is necessary to evaluate the strength of the parts manufactured using 3D printing technology.Design/methodology/approachIn this study, the effect of three print parameters − raster angle, build orientation and infill − on the tensile characteristics of 3D-printed components made of three distinct materials − acrylonitrile styrene acrylate (ASA), polycarbonate ABS (PC-ABS) and ULTEM-9085 − was investigated. A variety of test items were created using a commercially accessible 3D printer in various configurations, including raster angle (0°, 45°), (0°, 90°), (45°, −45°), (45°, 90°), infill density (solid, sparse, sparse double dense) and orientation (flat, on-edge).FindingsThe outcome shows that variations in tensile strength and force are brought on by the effects of various printing conditions. In all possible combinations of the print settings, ULTEM 9085 material has a higher tensile strength than ASA and PC-ABS materials. ULTEM 9085 material’s on-edge orientation, sparse infill, and raster angle of (0°, −45°) resulted in the greatest overall tensile strength of 73.72 MPa. The highest load-bearing strength of ULTEM material was attained with the same procedure, measuring at 2,932 N. The tensile strength of the materials is higher in the on-edge orientation than in the flat orientation. The tensile strength of all three materials is highest for solid infill with a flat orientation and a raster angle of (45°, −45°). All three materials show higher tensile strength with a raster angle of (45°, −45°) compared to other angles. The sparse double-dense material promotes stronger tensile properties than sparse infill. Thus, the strength of additive components is influenced by the combination of selected print parameters. As a result, these factors interact with one another to produce a high-quality product.Originality/valueThe outcomes of this study can serve as a reference point for researchers, manufacturers and users of 3D-printed polymer material (PC-ABS, ASA, ULTEM 9085) components seeking to optimize FDM printing parameters for tensile strength and/or identify materials suitable for intended tensile characteristics.

PurposeThis study aims to reveal the influences of three-dimensional (3D) printing parameters such as layer heights (0.1 mm, 0.2 mm and 0.4 mm), infill rates (40, 70 and 100%) and geometrical property as tapered angle (0, 0.25 and 0.50) on vibrational behavior of 3D-printed polyethylene terephthalate glycol (PET-G) tapered beams with fused filament fabrication (FFF) method.Design/methodology/approachIn this performance, all test specimens were modeled in AutoCAD 2020 software and then 3D-printed by FFF. The effects of printing parameters on the natural frequencies of 3D-printed PET-G beams with different tapered angles were also analyzed experimentally, and numerically (finite element analysis) via Ansys APDL 16 program. In addition to vibrational properties, tensile strength, elasticity modulus, hardness, and surface roughness of the 3D-printed PET-G parts were examined.FindingsIt can be stated that average surface roughness values ranged between 1.63 and 6.91 µm. In addition, the highest and lowest hardness values were found as 68.6 and 58.4 Shore D. Tensile strength and elasticity modulus increased with the increase of infill rate and decrease of the layer height. In conclusion, natural frequency of the 3D-printed PET-G beams went up with higher infill rate values though no critical change was observed for layer height and a change in tapered angle fluctuated the natural frequency values significantly.Research limitations/implicationsThe influence of printing parameters on the vibrational properties of 3D-printed PET-G beams with different tapered angles was carried out and the determination of these effects is quite important. On the other hand, with the addition of glass or carbon fiber reinforcements to the PET-G filaments, the material and vibrational properties of the parts can be examined in future works.Practical implicationsAs a result of this study, it was shown that natural frequencies of the 3D-printed tapered beams from PET-G material can be predicted via finite element analysis after obtaining material data with the help of mechanical/physical tests. In addition, the outcome of this study can be used as a reference during the design of parts that are subjected to vibration such as turbine blades, drone arms, propellers, orthopedic implants, scaffolds and gears.Social implicationsIt is believed that determination of the effect of the most used 3D printing parameters (layer height and infill rate) and geometrical property of tapered angle on natural frequencies of the 3D-printed parts will be very useful for researchers and engineers; especially when the importance of resonance is known well.Originality/valueWhen the literature efforts are scanned in depth, it can be seen that there are many studies about mechanical or wear properties of the 3D-printed parts. However, this is the first study which focuses on the influences of the both 3D printing parameters and tapered angles on the vibrational behaviors of the tapered PET-G beams produced with material extrusion based FFF method. In addition, obtained experimental results were also supported with the performed finite element analysis.

Three-dimensional (3D) cell printing is rapidly redefining how we engineer tissues by enabling the precise delivery of living cells within bio-inks to build complex, cell-laden structures. Unlike traditional approaches that seed cells onto inert scaffolds, this technique allows direct integration of cells into the construct, promoting enhanced cell infiltration, extracellular matrix (ECM) remodeling, and tissue-like functionality. Despite the explosion of interest, the field remains fragmented, with limited efforts to unify emerging data across platforms and applications. Our review addresses this gap by synthesizing recent advances in 3D cell printing in terms of key printing factors and parameters and adaptive bioprinting, presenting consensus and translative information such as printing parameters, identifying current established applications, and proposing future research directions based on the currentin vivoor clinical results. We map current trends across biomaterial choices-including gelatin, decellularized ECM, alginate, collagen I, and fibrin-and explore how diverse cell types, from primary human cells to engineered stem cell derivatives, are shaping the future of tissue fabrication. These innovations are already influencingin vivoresearch in skin regeneration, cartilage repair, and vascular grafts, while the high-resolution capabilities of 3D printing are powering next-generation organ-on-chip models. We conclude with key translational challenges and propose future research priorities to move from bench to bedside.

Zirconia-based ceramic has generated considerable interest in specialist structural/engineering ceramics. Among current available additive manufacturing methods for fabrication of ceramic components, the conventional material jetting systems are able to create local deposition of thin layers, dense green bodies, and complex shapes. However, this method is mainly limited to low viscous ceramic inks (mostly in the range of 20–40 mPa/s) with often less than 25 vol% solid loading which has restricted the widespread adoption of this technique. In this work, we employed a novel in-house developed hybrid drop-on-demand material jetting system (DODMJ) to deposit a highly viscous paste (up to 72 wt% solid content, a viscosity of 2100 mPa/s) of yttria-stabilized-zirconia (YSZ), with approximately 20 times higher speed than the current material jetting methods, for the first time. For this study, tetragonal zirconia polycrystal containing 8 wt% Y2O3 (5Y-TPZ), which is commonly used to produce dental restorations by subtractive manufacturing, was utilized. The printability of several visible light–curable zirconia pastes was studied in terms of the rheology, paste composition, solid content, and printing parameters. The density and porosity measurements as well as a two-stage sintering process to achieve fully dense and crack-free parts were carried out. The microstructure and internal features of the printed parts were also explored by X-ray nano-computed tomography (CT) scanning and scanning electron microscopy (SEM). In this work, standard test methods were also utilized to study the Vickers hardness and fracture toughness of the sintered 5Y-TPZ parts for the first time. The results showed that specimens produced with the paste containing 62.3 wt% solid loading yielded a relative density of 99.5% and presented an average fracture toughness and micro-hardness of 5.62 MPa/m0.5 and 1516 HV, respectively. Overall, the outcomes presented in this work confirmed that the novel DODMJ technique adopted for this study has great potential in the development of a feasible, high-speed, and cost-effective manufacturing system to produce zirconia ceramic parts with adequate mechanical and structural properties that meet the demanding requirements for various applications such as dental crowns restoration.

PurposeThe purpose of this study is to cover the influence of selected printing parameters at a macro and micro-geometrical level, focusing on the dimensions, geometry and surface of printed parts with short carbon fibers reinforced PLA. For this case study, a hollow cylindrical shape is considered, aiming to cover the gap detected in previous works analyzed.Design/methodology/approachNowadays, additive manufacturing plays a very important role in the manufacturing industry, as can be seen through its numerous research and applications that can be found. Within the engineering industry, geometrical tolerances are essential for the functionality of the parts and their assembly, but the variability in three-dimensional (3D) printing makes dimensional control a difficult task. Constant development in 3D printing allows, more and more, printed parts with controlled and narrowed geometrical deviations and tolerances. So, it is essential to continue narrowing the studies to achieve the optimal printed parts, optimizing the manufacturing process as well.FindingsResults present the relation between the selected printing parameters and the resulting printed part, showing the main deviations and the eligible values to achieve a better tolerance control. Also, from these results obtained, we present a parametric model that relates the geometrical deviations considered in this study with the printing parameters. It can provide an overview of the piece before printing it and so, adjusting the printing parameters and reducing time and number of printings to achieve a good part.Originality/valueThe main contribution is the study of the geometry selected under a 3D printing process, which is important because it considers parts that are created to fit together and need to comply with the required tolerances. Also, we consider that the parametric model can be a suitable approach to selecting the optimal printing parameters before printing.

Three‐dimensional (3D) printing becomes an attractive technique to fabricate tissue engineering scaffolds through its high control on fabrication and repeatability using the printing parameters. This technique can be combined by the finite element method (FEM), and tissue‐specific scaffolds with desirable morphological and mechanical properties can be designed and manufactured. In this study, the influential 3D printing parameters on the morphological and mechanical properties of polycaprolactone (PCL) filament and scaffold were studied experimentally and numerically. First, the effects of printing parameters and process on the properties of extruded PCL filament were investigated. Then, using FEM, the effects of filament specifications on the overall characteristics of the scaffold were evaluated. Results showed that both the printing process in terms of resting time and remaining time and the printing parameters like pressure, printing speed, and printing path length have influenced the filament properties. In addition, both the filament diameter and elastic modulus had significant effects on the properties of scaffold especially, a 20% increase in the filament diameter caused the scaffold compressive elastic modulus to rise by around 72%. It is concluded that the printing parameters and process must be tuned very well in fabricating scaffolds with the desired morphology and mechanical property.

PurposeThe purpose of this paper is to investigate and discuss the influence of printing parameters on the mechanical properties of acrylonitrile butadiene styrene (ABS) print by fused deposition modelling (FDM). The mechanical properties of ABS are highly influenced by printing parameters, and they determine the final product quality of printed pieces.Design/methodology/approachFor the paper’s purpose, five main parameters (extrusion temperature, infill pattern, air gap, printing speed and layer thickness) were selected and varied during ABS printing on an open-source and self-replicable FDM printer. Three different colors of commercially available ABS were also used to investigate color and printing parameter’s influence on the tensile strength.FindingsThe research results suggest that two parameters (infill pattern and layer thickness) were most influential on the mechanical properties of print ABS, being able to enhance its tensile strength. Another key influential factor was material color selected prior to printing, which influenced the tensile strength of the print specimen.Originality/valueThis study provides information on print parameters’ influence on the tensile strength of ABS print on replicable open-source three-dimensional (3D) printers. It also suggests the influence of materials’ color on print pieces’ tensile strength, indicating a new parameter for materials selection for 3D printing.

Background: Precision medicine refers to the formulation of personalized drug regimens according to the individual characteristics of patients to achieve optimal efficacy and minimize adverse reactions. Additive manufacturing (AM), also known as three-dimensional (3D) printing, has emerged as an optimal solution for precision drug delivery, enabling customizable and the fabrication of multifunctional structures with precise control over morphology and release behavior in pharmaceutics. However, the influence of 3D printing parameters on the printed tablets, especially regarding in vitro and in vivo performance, remains poorly understood, limiting the optimization of manufacturing processes for controlled-release profiles. Objective: To establish the fabrication process of 3D-printed controlled-release tablets via comprehensively understanding the printing parameters using fused deposition modeling (FDM) combined with hot-melt extrusion (HME) technologies. HPMC-AS/HPC-EF was used as the drug delivery matrix and carbamazepine (CBZ) was used as a model drug to investigate the in vitro drug delivery performance of the printed tablets. Methodology: Thermogravimetric analysis (TGA) was employed to assess the thermal compatibility of CBZ with HPMC-AS/HPC-EF excipients up to 230 °C, surpassing typical processing temperatures (160–200 °C). The formation of stable amorphous solid dispersions (ASDs) was validated using differential scanning calorimetry (DSC), hot-stage polarized light microscopy (PLM), and powder X-ray diffraction (PXRD). A 15-group full factorial design was then used to evaluate the effects of the fan speed (20–100%), platform temperature (40–80 °C), and printing speed (20–100 mm/s) on the tablet properties. Response surface modeling (RSM) with inverse square-root transformation was applied to analyze the dissolution kinetics, specifically t50% (time for 50% drug release) and Q4h (drug released at 4 h). Results: TGA confirmed the thermal compatibility of CBZ with HPMC-AS/HPC-EF, enabling stable ASD formation validated by DSC, PLM, and PXRD. The full factorial design revealed that printing speed was the dominant parameter governing dissolution behavior, with high speeds accelerating release and low speeds prolonging release through porosity-modulated diffusion control. RSM quadratic models showed optimal fits for t50% (R2 = 0.9936) and Q4h (R2 = 0.9019), highlighting the predictability of release kinetics via process parameter tuning. This work demonstrates the adaptability of polymer composite AM for tailoring drug release profiles, balancing mechanical integrity, release kinetics, and manufacturing scalability to advance multifunctional 3D-printed drug delivery devices in pharmaceutics.

Three-dimensional (3D) printers have been applied in many fields, including engineering and the medical sciences. In the pharmaceutical field, approval of the first 3D-printed tablet by the U.S. Food and Drug Administration in 2015 has attracted interest in the manufacture of tablets and drugs by 3D printing techniques as a means of delivering tailor-made drugs in the future. In current study, polyvinylalcohol (PVA)-based tablets were prepared using a fused-deposition-modeling-type 3D printer and the effect of 3D printing conditions on tablet production was investigated. Curcumin, a model drug/fluorescent marker, was loaded into PVA-filament. We found that several printing parameters, such as the rate of extruding PVA (flow rate), can affect the formability of the resulting PVA-tablets. The 3D-printing temperature is controlled by heating the print nozzle and was shown to affect the color of the tablets and their curcumin content. PVA-based infilled tablets with different densities were prepared by changing the fill density as a printing parameter. Tablets with lower fill density floated in an aqueous solution and their curcumin content tended to dissolve faster. These findings will be useful in developing drug-loaded PVA-based 3D objects and other polymer-based articles prepared using fused-deposition-modeling-type 3D printers.

Conditions of green body preparation and consequently the conditions of sintering are prerequisite for the preparation of dense samples of Al2O3 with superior optical and mechanical properties. The goal of this work was to determine the optimum forming conditions for preparation of green body, and to find out the optimal sintering regime facilitating the preparation of ultra-fine grained high purity alumina with maximal density, fine microstructure and small pore size. Axial pressing followed by CIP was found to yield green body with the highest density and narrowest pore size distribution. In the two-stage sintering regime the temperature T1 has to be higher or equal to 1300?C to obtain closed porosity unstable against shrinkage. The temperature T2 ? 1130?C was found to be too high for suppression of grain growth in the final stage of sintering and sintering trajectory was identical with that from standard sintering regime.

In this work we present the electrochemical and photoelectrochemical characterization of NiO thin films [thickness (l) range: 2 ≤ l ≤ 4 μm], which have been obtained from screen-printing of three precursor-pastes. All three pastes contained preformed NiO nanoparticles [diameter (Ø) range: 20 < Ø < 50 nm], but differed for the content and nature of the acidic component. The resulting NiO samples were employed as photoactive cathodes of p-type dye-sensitized solar cells (p-DSCs). The temperature of sintering was kept below 450°C to warrant mesoporosity and electrical connectivity between the nanostructured domains while maintaining a good level of adhesion on the substrate. The photoelectrochemical properties of bare and erythrosine b (ERY)-sensitized NiO in p-DSCs depended on the composition of the screen-printing paste. The NiO samples obtained from the pastes with the lowest amount of acidic component or containing the acid with the stronger character, namely HCl, gave the best performances in the corresponding p-DSCs. In the series of ERY-based p-DSCs here tested the most performing screen-printed electrode gave the largest overall conversion efficiency (η > 0.04%) and highest external quantum efficiency (EQE > 9% at 830 nm) with respect to the p-DSCs with NiO photocathodes of similar thickness, which have been prepared via different methods of deposition.

Sintering regimes and resulting microstructure and properties of binder jet 3D printed Ni-Mn-Ga magnetic shape memory alloys