The purpose of this study was to find and optimize the process parameters of producing tool steel 1.2709 at a layer thickness of 100 μm by DMLS (Direct Metal Laser Sintering). HPDC (High Pressure Die Casting) tools are printed from this material. To date, only layer thicknesses of 20-50 μm are used, and parameters for 100 µm were an undescribed area, according to the state of the art. Increasing the layer thickness could lead to time reduction and higher economic efficiency. The study methodology was divided into several steps. The first step was the research of the single-track 3D printing parameters for the subsequent development of a more accurate description of process parameters. Then, in the second step, volume samples were produced in two campaigns, whose porosity was evaluated by metallographic and CT (computed tomography) analysis. The main requirement for the process parameters was a relative density of the printed material of at least 99.9%, which was achieved and confirmed using the parameters for the production of the samples for the tensile test. Therefore, the results of this article could serve as a methodological procedure for optimizing the parameters to streamline the 3D printing process, and the developed parameters may be used for the productive and quality 3D printing of 1.2709 tool steel.
- Keywords
- 3D printing, 3D printing parameters optimization, Direct Metal Laser Sintering (DMLS), additive manufacturing, energy density, layer thickness,
- Publication type
- Journal Article MeSH
BACKGROUND: The presented study investigates the application of bi-arterial 3D printed models to guide transseptal puncture (TSP) in left atrial appendage closure (LAAC). AIMS: The objectives are to (1) test the feasibility of 3D printing (3DP) for TSP guidance, (2) analyse the distribution of the optimal TSP locations, and (3) define a CT-derived 2D parameter suitable for predicting the optimal TSP locations. METHODS: Preprocedural planning included multiplanar CT reconstruction, 3D segmentation, and 3DP. TSP was preprocedurally simulated in vitro at six defined sites. Based on the position of the sheath, TSP sites were classified as optimal, suboptimal, or nonoptimal. The aim was to target the TSP in the recommended position during the procedure. Procedure progress was assessed post hoc by the operator. RESULTS: Of 68 screened patients, 60 patients in five centers (mean age of 74.68 ± 7.64 years, 71.66% males) were prospectively analyzed (3DP failed in one case, and seven patients did not finally undergo the procedure). In 55 patients (91.66%), TSP was performed in the optimal location as recommended by the 3DP. The optimal locations for TSP were postero-inferior in 45.3%, mid-inferior in 45.3%, and antero-inferior in 37.7%, with a mean number of optimal segments of 1.34 ± 0.51 per patient. When the optimal TSP location was achieved, the procedure was considered difficult in only two (3.6%) patients (but in both due to complicated LAA anatomy). Comparing anterior versus posterior TSP in 2D CCT, two parameters differed significantly: (1) the angle supplementary to the LAA ostium and the interatrial septum angle (160.83° ± 9.42° vs. 146.49° ± 8.67°; p = 0.001), and (2) the angle between the LAA ostium and the mitral annulus (95.02° ± 3.73° vs. 107.38° ± 6.76°; p < 0.001), both in the sagittal plane. CONCLUSIONS: In vitro TSP simulation accurately determined the optimal TSP locations for LAAC and facilitated the procedure. More than one-third of the optimal TSP sites were anterior.
- Keywords
- 3D printing, computed tomography, left atrial appendage closure, transseptal puncture,
- MeSH
- Printing, Three-Dimensional MeSH
- Atrial Fibrillation * therapy surgery MeSH
- Humans MeSH
- Tomography, X-Ray Computed MeSH
- Punctures methods MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Atrial Appendage * diagnostic imaging surgery MeSH
- Treatment Outcome MeSH
- Check Tag
- Humans MeSH
- Male MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
OBJECTIVE: Precise control over the ultrasound field parameters experienced by biological samples during sonication experiments in vitro may be quite challenging. The main goal of this work was to outline an approach to construction of sonication test cells that would minimize the interaction between the test cells and ultrasound. METHODS: Optimal dimensions of the test cell were determined through measurements conducted in a water sonication tank using 3D-printed test objects. The offset of local acoustic intensity variability inside the sonication test cell was set to value of ±50% of the reference value (i.e., local acoustic intensity measured at last axial maximum in the free-field condition). The cytotoxicity of several materials used for 3D printing was determined using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay. RESULTS: The sonication test cells were 3D printed from polylactic acid material, which was not toxic to the cells. Silicone membrane HT-6240, which was used to construct the bottom of the test cell, was found to reduce ultrasound energy minimally. Final ultrasound profiles inside the sonication test cells indicated the desired variability of local acoustic intensity. The cell viability in our sonication test cell was comparable to that of commercial culture plates with bottoms constructed with silicone membrane. CONCLUSION: An approach to construction of sonication test cells minimizing the interaction of the test cell and ultrasound has been outlined.
- Keywords
- Optimization of sonication test cell, Sonication experiments, Therapeutic ultrasound, Ultrasound field,
- MeSH
- Printing, Three-Dimensional MeSH
- High-Intensity Focused Ultrasound Ablation * methods MeSH
- Silicones MeSH
- Ultrasonography MeSH
- Sonication * methods MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Silicones MeSH
This paper is primarily concerned with determining and assessing the properties of a cement-based composite material containing large particles of aggregate in digital manufacturing. The motivation is that mixtures with larger aggregate sizes offer benefits such as increased resistance to cracking, savings in other material components (such as Portland cement), and ultimately cost savings. Consequently, in the context of 3D Construction/Concrete Print technology (3DCP), these materials are environmentally friendly, unlike the fine-grained mixtures previously utilized. Prior to printing, these limits must be established within the virtual environment's process parameters in order to reduce the amount of waste produced. This study extends the existing research in the field of large-scale 3DCP by employing coarse aggregate (crushed coarse river stone) with a maximum particle size of 8 mm. The research focuses on inverse material characterization, with the primary goal of determining the optimal combination of three monitored process parameters-print speed, extrusion height, and extrusion width-that will maximize buildability. Design Of Experiment was used to cover all possible variations and reduce the number of required simulations. In particular, the Box-Behnken method was used for three factors and a central point. As a result, thirteen combinations of process parameters covering the area of interest were determined. Thirteen numerical simulations were conducted using the Abaqus software, and the outcomes were discussed.
This paper presents the design, development, and optimization of a 3D printed micro horizontal axis wind turbine blade made of PLA material. The objective of the study was to produce 100 watts of power for low-wind-speed applications. The design process involved the selection of SD7080 airfoil and the determination of the material properties of PLA and ABS. A structural analysis of the blade was carried out using ANSYS software under different wind speeds, and Taguchi's L16 orthogonal array was used for the experiments. The deformation and equivalent stress of the PLA material were identified, and the infill percentage and wind speed velocity were optimized using the moth-flame optimization (MFO) algorithm. The results demonstrate that PLA material has better structural characteristics compared to ABS material. The optimized parameters were used to fabricate the turbine blades using the fusion deposition modeling (FDM) technique, and they were tested in a wind tunnel.
- Keywords
- MFO, PSO, airfoil profile, fusion deposition modeling, micro horizontal axis wind turbine, structure analysis,
- Publication type
- Journal Article MeSH
This study presents a comprehensive experimental investigation into the impact resistance of stacked composite structures fabricated by hybridizing 3D-printed carbon fiber-reinforced polyether ether ketone (CF-PEEK) with perforated aluminum (Al 3004) foil layers. Both perforated and unperforated Al foil, strategically interleaved within CF-PEEK layers and bonded using epoxy resin. Two critical fabrication parameters fiber orientation (0°, 45°, and 90°) and layer height (0.2 mm, 0.3 mm, and 0.4 mm) were systematically varied using a full factorial design to assess their influence on impact performance. Charpy impact tests were conducted in accordance with ASTM D6110 on both hybrid CF-PEEK/Al foil laminates and CF-PEEK-only specimens. Results indicated a substantial improvement in impact energy absorption and impact strength for the hybrid configurations, with peak values reaching up to 30 J and 402.2 J/m2, respectively at a fiber orientation of 90° and a layer height of 0.2 mm. In contrast, corresponding CF-PEEK-only specimens exhibited significantly lower energy absorption, with maximum values of 17 J and 227.9 J/m2 under the same conditions. Among all parameter combinations, the hybrid specimens with a fiber orientation of 45° and a layer height of 0.3 mm demonstrated the most consistent and enhanced performance. These findings highlight the synergistic effect of metallic reinforcement and optimized printing parameters improves mechanical robustness of additively manufactured composite laminates. This work emphasizes the potential of hybrid additive manufacturing (HAM) approaches in developing lightweight, high-strength materials for aerospace, defense, and impact-critical applications, offering a promising pathway for tailoring structural performance through designable interfacial architectures and controlled fabrication parameters.
- Keywords
- 3D printing, Additive manufacturing, Aluminum foil, CF-PEEK composites, FFF, Fiber orientation, Hybrid laminates, Impact resistance, Layer height, Perforated aluminum foil,
- Publication type
- Journal Article MeSH
Bioprinting is a modern tool suitable for creating cell scaffolds and tissue or organ carriers from polymers that mimic tissue properties and create a natural environment for cell development. A wide range of polymers, both natural and synthetic, are used, including extracellular matrix and collagen-based polymers. Bioprinting technologies, based on syringe deposition or laser technologies, are optimal tools for creating precise constructs precisely from the combination of collagen hydrogel and cells. This review describes the different stages of bioprinting, from the extraction of collagen hydrogels and bioink preparation, over the parameters of the printing itself, to the final testing of the constructs. This study mainly focuses on the use of physically crosslinked high-concentrated collagen hydrogels, which represents the optimal way to create a biocompatible 3D construct with sufficient stiffness. The cell viability in these gels is mainly influenced by the composition of the bioink and the parameters of the bioprinting process itself (temperature, pressure, cell density, etc.). In addition, a detailed table is included that lists the bioprinting parameters and composition of custom bioinks from current studies focusing on printing collagen gels without the addition of other polymers. Last but not least, our work also tries to refute the often-mentioned fact that highly concentrated collagen hydrogel is not suitable for 3D bioprinting and cell growth and development.
- Keywords
- bioink, bioprinting, bioprinting parameters, collagen, hydrogel, hydrogel properties,
- Publication type
- Journal Article MeSH
- Review MeSH
This study focuses on selecting a suitable 3D printer and defining experimental methods to gather the necessary data for determining the optimal filament material for printing components of the VEX GO and VEX IQ robotic kits. The aim is to obtain the required data to identify an appropriate filament material and set 3D printing parameters to achieve the desired mechanical properties of the parts while maintaining cost-effectiveness. Another key objective is achieving optimal operational functionality, ensuring the required part performance with minimal printing costs. It is desirable for the modeled and printed parts to exhibit the required mechanical properties while maintaining economic efficiency. Another crucial aspect is achieving optimal functionality of the produced parts with minimal printing costs. This will be assessed by analyzing the impact of key 3D printing technology parameters, focusing in this research phase on material selection. The criteria for selecting filament materials include ease of printability under the conditions of primary and secondary schools, simplicity of printing, minimal need for post-processing, and adequate mechanical properties verified through experimental measurements and destructive tests on original parts from VEX GO and VEX IQ kits. The study analyzed various filaments regarding their mechanical properties, printability, and cost-effectiveness. The most significant practical contribution of this study is selecting a suitable filament material tested through a set of destructive tests, emphasizing maintaining the mechanical properties required for the real-life application of the parts. This includes repetitive assembly and disassembly of various robotic model constructions and their activation for demonstration purposes and applications of STEM/STEAM/STREAM methods in the educational process to achieve the properties of original components. Additionally, the study aims to set up 3D printing such that even a beginner-level operator, such as a primary or secondary school student under the supervision of their teacher or a teacher with minimal knowledge and experience in 3D printing, can successfully execute it. Further ongoing research focuses on evaluating the effects of characteristic 3D printing parameters, such as infill and perimeter, on the properties of 3D-printed parts through additional measurements and analyses.
- Keywords
- 3D printing, ABS, ASA, PETG, PLA, VEX, VEX IQ, deflection, destructive tests, education, filament, kits, model, robotics, tensile load,
- Publication type
- Journal Article MeSH
Additive manufacturing offers great potential for various industrial solutions; in particular, the binder jetting method enables the production of components from various materials, including sand molds for casting. This work presents the results of an extensive set of experiments aimed at enhancing the structural strengthening of 3D-printed sand molds. Structural strengthening was achieved by impregnating the sand-printed structures with two polymer materials: epoxy resin and silicone varnish. Impregnation was performed with variable parameters, such as temperature, pressure, and time. Structural strengthening using polymers was investigated by analyzing the flexural strength and impact resistance of the impregnated products and comparing these obtained values with the reference material in terms of impregnation parameters and the polymer used. Microstructural observations and an analysis of the pore filling were also performed. This approach allowed for a full assessment of the influence of processing parameters and the type of polymer used for impregnation on the properties of sand-printed structures, which allowed for identifying the most optimal method to be used to strengthen the sand molds for casting the components for electrical devices. As a direct proof of concept, it was shown that impregnation with polymeric materials could effectively strengthen the sand mold, increasing its flexural strength and impact resistance by over 20 times and 5 times, respectively. A full-scale mold was printed using binder jetting, impregnated with epoxy resin at 65 °C, and used to successfully fabricate a fully functional electrification device.
- Keywords
- additive manufacturing, polymer impregnation, sand mold, structural strengthening,
- Publication type
- Journal Article MeSH
Fused Deposition Modeling (FDM) is a common additive manufacturing technique known for its ability to quickly produce complex geometries and features according to customer requirements in a short timeframe. Parts produced by FDM technique with (Polylactic Acid) PLA can be used extensively as it is biocompatible in nature. The present investigation involves drilling the fabricated circular discs to assess the material removal rate (MRR) and hole profile. The inputs considered are spindle speed (SS), feed rate (fr), and drill diameter (dia), in relation to the output characteristics such as MRR, surface roughness (Ra and Rz), circularity, and cylindricity. This work employs the Proximity Indexed Value (PIV) tool to predict the near-optimal value for improving hole quality and enhancing the drilling process. In addition, Artificial neural network (ANN), Support vector machine (SVM), and Random Forest (RF) models were employed to predict the optimized results by PIV method. The tests show that the RF model, which has a R² value of 99.16%, does a better job of describing the desired outcome than the ANN model (89.45%) and the SVM model (89.08%). This also proves that the machine learning (ML) models offer better prediction to the optimization of drilling parameters with reference to the quality of the workpiece machined.
