Three-dimensional Printing Technology Research Articles

Технология изготовления образцов из композитных материалов для проведения лабораторных испытаний

Based on the accumulated experience of the staff of the Institute of Marine Technologies, Energy and Transport of the Astrakhan State Technical University, the development of the production of various parts of ship hulls, elements of main and auxiliary power plants, including various fasteners and stanchions, using additive technology and other methods of forming composite materials has begun. During the implementation of the developed direction, issues arise of reducing the cost, weight of manufactured parts and improving the characteristics of sound absorption, sound insulation, vibration isolation, etc. Despite the fact that adhesives based on epoxy or polyester resin, according to technical documentation, are fast-curing adhesives, they are not applicable for the production of products using three-dimensional printing technologies. for several reasons. The factors preventing the use of materials for the production of such parts are listed: the minimum curing time of one layer of glue under optimal conditions is from one and a half hours or more, which significantly increases the interlayer time interval; the glue layer is not a self-supporting structure due to the fact that it is in a liquid state during the induction period; products made of this adhesive without reinforcement cannot withstand the required dynamic loads. In the process of experimental studies, a number of formulations based on polyester resin with different fillers were obtained, which have the necessary consistency to apply layers on top of the previous one without waiting for curing, and also contain the necessary amount of reinforcing material and other fillers required to solve problems related to vibration isolation and sound insulation.

3D printing and bioprinting in the battle against diabetes and its chronic complications

Diabetes is a metabolic disorder characterized by high blood sugar. Uncontrolled blood glucose affects the circulatory system in an organism by intervening blood circulation. The high blood glucose can lead to macrovascular (large blood vessels) and microvascular (small blood vessels) complications. Due to this, the vital organs (notably brain, eyes, feet, heart, kidneys, lungs and nerves) get worsen in diabetic patients if not treated at the earliest. Therefore, acquiring treatment at an appropriate time is very important for managing diabetes and other complications that are caused due to diabetes. The root cause for the occurrence of various health complications in diabetic patients is the uncontrolled blood glucose levels. This review presents a consolidated account of the applications of various types of three-dimensional (3D) printing and bioprinting technologies in treating diabetes as well as the complications caused due to impaired blood glucose levels. Herein, the development of biosensors (for the diagnosis), oral drug formulations, transdermal drug carriers, orthotic insoles and scaffolds (for the treatment) are discussed. Next to this, the fabrication of 3D bioprinted organs and cell-seeded hydrogels (pancreas engineering for producing insulin and bone engineering for managing bone defects) are explained. As the final application, 3D bioprinting of diabetic disease models for high-throughput screening of ant-diabetic drugs are discussed. Lastly, the challenges and future perspective associated with the use of 3D printing and bioprinting technologies against diabetes and its related chronic complications have been put forward.

Accuracy assessment between computer-guided surgery planning and actual tooth position during tooth autotransplantation.

This study aims to evaluate the precision and efficacy of utilizing computer-aided design (CAD) in combination with three-dimensional printing technology for tooth transplantation. This study analysed 50 transplanted teeth from 48 patients who underwent tooth transplantation surgery with the aid of CAD and positional guides. A consistent coordinate system was established using preoperative and postoperative cone-beam computed tomography images. Linear displacements and angular deviations were calculated by identifying key regions in both virtual designs and actual transplanted teeth. Additionally, an analysis was conducted to explore potential factors influencing these deviations. The mean cervical deviation, apical deviation, and angular deviation among the 50 transplanted teeth were 1.16 ± 0.57 mm, 1.80 ± 0.94 mm, and 6.82 ± 3.14°, respectively. Cervical deviation was significantly smaller than apical deviation. No significant difference in deviation was observed among different recipient socket locations, holding true for both single-root, and multi-root teeth. However, a significant difference was noted in apical deviation between single-root and multi-root teeth. Our analysis identified a correlation between apical deviation and root length, leading to the development of a prediction model: Apical deviation = 0.1390 × (root length) + 0.2791. The postoperative position of the donor teeth shows discrepancies compared to preoperative simulation when utilizing CAD and 3D printed templates during autotransplantation procedures. Continual refinement of preoperative design is a crucial endeavour.

Feasibility and impact of three-dimensional (3D) printing technology in simulated teaching of congenital malformations

AimsThis study aimed to investigate the feasibility and effectiveness of utilizing three-dimensional (3D) printing technology in the simulation teaching of congenital malformations.MethodsWe conducted a comparative analysis between an experimental group that received traditional teaching supplemented with 3D printing model demonstrations and hands-on model operation, and a control group that received traditional teaching methods. Various parameters, including classroom interest, classroom interaction, learning enthusiasm, disease awareness, teaching satisfaction, and independent operation confidence, were assessed, along with theoretical and practical tests.ResultsThe results showed no significant difference in theoretical test scores between the two groups (91.92 ± 15.04 vs. 89.44 ± 14.89), but the practical test revealed a significantly higher number of qualified trainees in the experimental group compared to the control group (23 vs. 8). In terms of classroom engagement, both groups exhibited similar levels of interest (8.08 ± 1.52 vs. 8.74 ± 0.984), classroom interaction (7.88 ± 1.97 vs. 8.7 ± 1.33), learning enthusiasm (8.81 ± 1.021 vs. 8.52 ± 1.189), and disease awareness (8.58 ± 0.99 vs. 8.58 ± 0.99). However, the experimental group demonstrated significantly higher teaching satisfaction (8.81 ± 1.06 vs. 9.19 ± 0.96) and greater operation confidence (7.67 ± 2.56 vs. 5.5 ± 2.79) than the control group.Conclusion3D printing technology can be effectively utilized to create surgical teaching models, enhancing the confidence of standardized training doctors and improving teaching outcomes.

Amorphous solid dispersion of a binary formulation with felodipine and HPMC for 3D printed floating tablets

This study focuses on the combination of three-dimensional printing (3DP) and amorphous solid dispersion (ASD) technologies for the manufacturing of gastroretentive floating tablets. Employing hot melt extrusion (HME) and fused deposition modeling (FDM), the study investigates the development of drug-loaded filaments and 3D printed (3DP) tablets containing felodipine as model drug and hydroxypropyl methylcellulose (HPMC) as the polymeric carrier. Prior to fabrication, solubility parameter estimation and molecular dynamics simulations were applied to predict drug-polymer interactions, which are crucial for ASD formation. Physical bulk and surface characterization complemented the quality control of both drug-loaded filaments and 3DP tablets. The analysis confirmed a successful amorphous dispersion of felodipine within the polymeric matrix. Furthermore, the low infill percentage and enclosed design of the 3DP tablet allowed for obtaining low-density systems. This structure resulted in buoyancy during the entire drug release process until a complete dissolution of the 3DP tablets (more than 8 h) was attained. The particular design made it possible for a single polymer to achieve a zero-order controlled release of the drug, which is considered the ideal kinetics for a gastroretentive system. Accordingly, this study can be seen as an advancement in ASD formulation for 3DP technology within pharmaceutics.

Ultrasound treatment improved the physicochemical properties of pea protein with pectin ink used for 3D printing

Pectin, as a gelling agent enhancer, is capable of augmenting the strength of plant protein gels; however, their direct blending often results in insignificant crosslinking efficiency. The application of ultrasonication has been found to effectively promote crosslinking interactions between pectin and plant proteins. This study primarily probes into the physicochemical impacts on the pea protein system instigated by ultrasonicated apple pectin (AP), citrus pectin (CP), and high methoxyl pectin (HM) variances. It has been revealed that the incorporation of pectin, subsequent to ultrasonication, ameliorates the textural and rheological traits of the pea protein matrix. Nevertheless, the introduction of high methoxyl pectin excessively enhances these identical properties, rendering it unsuitable for use in food development and three-dimensional (3D) printing technologies. Under an ultrasound power setting of 390 W, the citrus pectin variant outperforms other variants with its superior hardness, elasticity, and viscoelasticity, thereby significantly bolstering the self-supporting capability and malleability of the pea protein system for potential utilization in 3D printing applications. In conclusion, the ultrasonically treated pectin-pea protein amalgam optimizes the physicochemical attributes of the pea protein system, contributing to the stability enhancement of 3D printed products.

Improved broadband design of SiC/MWCNT absorbing materials through synergistic regulation of heterointerface structure and triple periodic minimal surface meta-structure

SiC/multi-walled carbon nanotube (MWCNT) composites are considered to be promising materials for high-temperature electromagnetic wave (EMW) absorption due to their strong thermal stability and tunable dielectric properties. However, the EMW absorption performance of these composites is limited by poor impedance matching. This study proposes a novel multiscale structure synergistic regulation approach to enhance EMW absorption performance, which involves constructing a heterointerface structure and a triple periodic minimal surface (TPMS) meta-structure. The addition of a SiO2 shell as an impedance layer to the SiC/MWCNT core to improve the intrinsic impedance. Meanwhile, the heterointerface between the core-shell structure leads to multiple interface polarization, significantly enhancing EMW energy dissipation. Consequently, the effective absorption bandwidth (EAB) of SiO2–SiC/MWCNT composites increased from 0.88 to 4.56 GHz. Furthermore, a TPMS meta-structure, fabricated by three-dimensional (3D) printing and sol infiltration technology, is developed to further improve impedance matching with the equivalent electromagnetic effect. Simulation and experimental results demonstrate that the SiO2–SiC/MWCNT TPMS meta-structure exhibits broadband EMW absorption performance, with the EAB reaching 7.2 GHz. This improvement is attributed to the synergistic regulation of the heterointerface structure and TPMS meta-structure, which provides a good balance between the requirements of electromagnetic loss and impedance matching. Additionally, the composites exhibit excellent oxidation resistance, as their EAB remains almost unchanged after exposure to 1000 °C for 6 h. This research offers a new design paradigm for ultrabroadband design of the nonmagnetic high-temperature absorbing materials.

Mechanical, physical and thermal properties of polylactic acid filament composite reinforced with newly isolated Cryptostegia grandiflora fiber

By leveraging the properties of natural or plant fibers and possibilities through three-dimensional (3D) printing technology, a composite filament was fabricated by incorporating newly isolated Cryptostegia grandiflora fiber (CGF), as a reinforcement with polylactic acid (PLA) by using a twin-screw extruder. The fabricated composite filament and pure PLA filament were 3D-printed, using fused deposition modeling (FDM). This study investigated the mechanical, physical, and thermal properties of the 3D-printed CGF reinforced composite filament samples. The mechanical properties of the samples fabricated with 10 wt% CGF were better than that of samples with pure PLA. In addition, impact, tensile, flexural strengths and hardness were increased by 35.6, 33.6, 14.1, and 1.7%, respectively, when compared with the sample with pure PLA. The fractured surface morphology of tensile samples showed a uniform distribution of CGF within the PLA. The addition of CGF improved the thermal stability of the 3D-printed CGF/PLA composite sample by 15%. Therefore, the printed structure could serve as an alternative material for various uses, considering contemporary concepts of sustainability, availability, environmental friendliness, and cost effectiveness.

Compressive Fracture Behavior of Zirconia/Resin Composites Prepared by Fused Deposition Modeling Combined with Vacuum Infiltration.

Although bioceramic materials exhibit good biocompatibilities and bone conductivities, their high brittleness and low toughness properties limit their applications. Zirconia (ZrO2)/resin composites with idealized structures and properties were prepared by fused deposition modeling (FDM) combined with a vacuum infiltration process. The porous structure was prepared using the FDM three-dimensional printing technology, with granular zirconia as the raw material, and the relationship between the pore shape, pore size, and deformation was discussed. The results showed that square pores were more suitable than honeycomb pores for printing small pore sizes, and the resolution was high. Scanning electron microscopy observations showed that the superposition of multiple printing paths promoted the emergence of hole defects. The effects of the resin and the pore shape on the compressive strengths of the composites were studied. It was found that the compressive strengths of the honeycomb pore ZrO2/resin composites and porous ceramics were superior to those of the square pore samples. The introduction of the resin had a significant effect on the compressive strengths of the composites. The compressive strength increased in the direction perpendicular to the pores, while it decreased in the direction parallel to the pores.

Patient-specific implants made of 3D printed bioresorbable polymers at the point-of-care: material, technology, and scope of surgical application

BackgroundBioresorbable patient-specific additive-manufactured bone grafts, meshes, and plates are emerging as a promising alternative that can overcome the challenges associated with conventional off-the-shelf implants. The fabrication of patient-specific implants (PSIs) directly at the point-of-care (POC), such as hospitals, clinics, and surgical centers, allows for more flexible, faster, and more efficient processes, reducing the need for outsourcing to external manufacturers. We want to emphasize the potential advantages of producing bioresorbable polymer implants for cranio-maxillofacial surgery at the POC by highlighting its surgical applications, benefits, and limitations.MethodsThis study describes the workflow of designing and fabricating degradable polymeric PSIs using three-dimensional (3D) printing technology. The cortical bone was segmented from the patient’s computed tomography data using Materialise Mimics software, and the PSIs were designed created using Geomagic Freeform and nTopology software. The implants were finally printed via Arburg Plastic Freeforming (APF) of medical-grade poly (L-lactide-co-D, L-lactide) with 30% β-tricalcium phosphate and evaluated for fit.Results3D printed implants using APF technology showed surfaces with highly uniform and well-connected droplets with minimal gap formation between the printed paths. For the plates and meshes, a wall thickness down to 0.8 mm could be achieved. In this study, we successfully printed plates for osteosynthesis, implants for orbital floor fractures, meshes for alveolar bone regeneration, and bone scaffolds with interconnected channels.ConclusionsThis study shows the feasibility of using 3D printing to create degradable polymeric PSIs seamlessly integrated into virtual surgical planning workflows. Implementing POC 3D printing of biodegradable PSI can potentially improve therapeutic outcomes, but regulatory compliance must be addressed.

AI-driven design of customized 3D-printed multi-layer capsules with controlled drug release profiles for personalized medicine

Personalized medicine aims to effectively and efficiently provide customized drugs that cater to diverse populations, which is a significant yet challenging task. Recently, the integration of artificial intelligence (AI) and three-dimensional (3D) printing technology has transformed the medical field, and was expected to facilitate the efficient design and development of customized drugs through the synergy of their respective advantages. In this study, we present an innovative method that combines AI and 3D printing technology to design and fabricate customized capsules. Initially, we discretized and encoded the geometry of the capsule, simulated the dissolution process of the capsule with classical drug dissolution model, and verified it by experiments. Subsequently, we employed a genetic algorithm to explore the capsule geometric structure space and generate a complex multi-layer structure that satisfies the target drug release profiles, including stepwise release and zero-order release. Finally, Two model drugs, isoniazid and acetaminophen, were selected and fused deposition modeling (FDM) 3D printing technology was utilized to precisely print the AI-designed capsule. The reliability of the method was verified by comparing the in vitro release curve of the printed capsules with the target curve, and the f2 value was more than 50. Notably, accurate and autonomous design of the drug release curve was achieved mainly by changing the geometry of the capsule. This approach is expected to be applied to different drug needs and facilitate the development of customized oral dosage forms.

Effect of a novel mesh design and the sandblasting technique on the bond strength of computer-designed and three-dimension laser printed resin bonded bridges: an in vitro study

Resin-bonded bridges (RBBs) are a minimally invasive and aesthetically pleasing treatment modality. However, their frequent failure has posed challenges for both dental professionals and patients. This necessitates the exploration of innovative strategies to enhance the longevity of RBBs. This study aimed to assess the bond strength of a mesh bridge fabricated using computer-aided design and three-dimensional (3D) printing technology in comparison to the traditional aluminum oxide sandblasting method. A total of 48 lower incisors were embedded in acrylic bases according to a standardized computer-generated model to receive 24 metal RBBs. The two groups underwent distinct metal surface treatments: the 3D mesh novel design and sandblasting with aluminum oxide particles sized at 250.00 µm. The bond strength of the bridges was evaluated, and statistical analysis was performed using the independent samples t-test with a significance level set at α = 0.05. The findings revealed a significant difference between the two methods (p < 0.001). The 3D mesh design exhibited a mean bond strength of 387.89 ± 24.15 N, while the sandblasting technique yielded a mean value of 161.46 ± 31.25 N. In summary, the 3D mesh design substantially enhanced the bond strength of RBBs compared to the traditional sandblasting technique.

Hydrodynamic metamaterial redirector for steering fluid flow in pipelines with arbitrary curvatures

Hydrodynamic metamaterial redirector for steering fluid flow in pipelines with arbitrary curvatures

The Role of 3D Custom Implants in Upper Extremity Surgery.

As the technology of three-dimensional (3D) printing becomes more refined and accessible, multiple applications of its use are becoming more commonplace in upper extremity surgery. 3D-printed models have been beneficial in preoperative planning of complex cases of acute trauma or malunions, contributing to spatial understanding or even contouring of implants. Custom guides can also be created to assist intraoperatively with precise placement of osteotomies or arthroplasty implants. Finally, custom 3D implants have been described for cases of bone loss in the upper extremity. This can be for relatively small gaps after malunion correction or extensive defects, typically for trauma or tumor. Articular defects can also be addressed with this technology, although special considerations should be given to the implant design and longevity in these situations. Because of the relatively recent nature of 3D implants, long-term data are lacking. However, they show great promise in an expanding range of challenging clinical indications.

Landslide model tests with a miniature 2D principal stress (PS) sensor

Understanding the stress distribution derived from monitoring the principal stress (PS) in slopes is of great importance. In this study, a miniature sensor for quantifying the two-dimensional (2D) PS in landslide model tests is proposed. The fundamental principle and design of the sensor are demonstrated. The sensor comprises three earth pressure gages and one gyroscope, with the utilization of three-dimensional (3D) printing technology. The difficulties of installation location during model preparation and sensor rotation during testing can be effectively overcome using this sensor. Two different arrangements of the sensors are tested in verification tests. Additionally, the application of the sensor in an excavated-induced slope model is tested. The results demonstrate that the sensor exhibits commendable performance and achieves a desirable level of accuracy, with a principal stress angle error of ±5° in the verification tests. The stress transformation of the slope model, generated by excavation, is demonstrated in the application test by monitoring the two miniature principal stress (MPS) sensors. The sensor has a significant potential for measuring primary stress in landslide model tests and other geotechnical model experiments.

Perioperative Considerations for Use of Custom Metallic Implants in Limb Reconstruction.

The surgical management of critical bone defects remains challenging. Regardless of whether bone loss is acute or the result of staged surgical resection, current surgical management often requires advanced reconstructive techniques, many of which require multiple surgical procedures and consistent patient involvement with applied internal or external orthopaedic devices. The utilization of three-dimensional (3D) printing technology has continued to expand across orthopaedic subspecialties; in orthopaedic trauma, custom metallic implants are being used in the management of critical bone defects. Implementation of this technique may be advantageous in certain clinical situations. The perioperative considerations for placement of a custom bone defect printed metallic implant are presented in conjunction with demonstrative clinical cases.

Surface Quality Related to Face Milling Parameters in 3D Printed Carbon Fiber-Reinforced PETG

Three-dimensional printing technology holds significant potential for enhancing the flexibility and cost-efficiency of producing carbon fiber-reinforced polymer composites (CFRPs). However, it faces limitations such as challenges in achieving high surface qualityand precise dimensional accuracy and managing the distinctive anisotropic mechanical properties that it demonstrates. This study aims to explore the machinability of 3D printed PETG infused with 20% short carbon fiber and to assess the resulting surface roughness and burr formation. Employing a Design of Experiments (DoE) approach, three factors were considered: rotational speed, feed rate, and depth of cut. These factors were tested at varying levels—rotational speeds of 3000, 5500, and 8000 rpm; feed rates of 400, 600, and 800 mm/min; and depth of cut values of 0.2, 0.4, 0.6, and 0.8 mm. The evaluation of machinability relied on two key response parameters: surface roughness (Sa) determined from the milled surface and burr height measured on both sides using a roughness meter. The findings revealed a significant influence of milling parameters on both roughness and burr formation. However, the ideal conditions for minimizing roughness and reducing burr formation did not align. Furthermore, a comparative analysis was conducted between these results and the machinability of PETG under similar conditions.

Three-dimensional printed pure-titanium implantation for chest wall reconstruction involving the sternum and ribs: a novel approach.

Chest wall reconstruction is challenging due to the complex shape and large defect size. The three-dimensional printing technology enables the fabrication of customized implants, and 3D-printed pure-titanium could provide superior mechanical properties to conventional materials. The aim of this study was to evaluate long-term outcomes of patients undergoing chest wall reconstruction with a 3D-printed pure-titanium implant. Between August 2018 and May 2021, 5 patients underwent surgery due to sternal metastasis (n = 3), postoperative sternal wound infection (n = 1) and deformity (n = 1). The customized implant was designed and constructed based on the size and shape of the chest wall defect measured on computed tomography. All patients demonstrated uneventful recovery without complications during the hospital course. During the median follow-up of 20 months, 1 patient underwent revision surgery due to implant breakage, and 1 removed the implant due to trauma-related chest wall infection. One patient died from cancer progression, while 3 patients are alive without any implant-related complications. Chest wall reconstruction using a 3D-printed pure-titanium implant could be a novel alternative for patients with various conditions affecting the sternum and ribs.

An evaluation of the usability and durability of 3D printed versus standard suture materials.

The capability to produce suture material using three-dimensional (3D) printing technology may have applications in remote health facilities where rapid restocking of supplies is not an option. This is a feasibility study evaluating the usability of 3D-printed sutures in the repair of a laceration wound when compared with standard suture material. The 3D-printed suture material was manufactured using a fused deposition modelling 3D printer and nylon 3D printing filament. Study participants were tasked with performing laceration repairs on the pigs' feet, first with 3-0 WeGo nylon suture material, followed by the 3D-printed nylon suture material. Twenty-six participants were enrolled in the study. Survey data demonstrated statistical significance with how well the 3D suture material performed with knot tying, 8.9 versus 7.5 (p = 0.0018). Statistical significance was observed in the 3D-printed suture's ultimate tensile strength when compared to the 3-0 Novafil suture (274.8 vs. 199.8 MPa, p = 0.0096). The 3D-printed suture also demonstrated statistical significance in ultimate extension when compared to commercial 3-0 WeGo nylon suture (49% vs. 37%, p = 0.0215). This study was successful in using 3D printing technology to manufacture suture material and provided insight into its usability when compared to standard suture material.

Optimization of 3D Printing Parameters for Alumina Ceramic Based on the Orthogonal Test.

In this paper, an alumina ink with good rheological properties was successfully prepared using pseudoboehmite as the main component, nitric acid as the colloidal solvent, and sesbania powder as the lubricant. The impact of nine different ink formulations, namely, Ink1 to Ink9, on the printability and rheological features of the ink was investigated. Consequently, it was found that Ink3 with 5 wt % nitric acid and 5 wt % sesbania powder exhibited the most favorable formability. This ink was utilized to fabricate alumina samples with direct ink writing (DIW) three-dimensional (3D) printing technology. The printed alumina samples were characterized using an automatic Brunauer-Emmett-Teller, X-ray diffractometer, Fourier transform infrared spectroscopy, and scanning electron microscope. To obtain the optimal printing parameters, a three-factor and three-level orthogonal test was designed to research the influences of different 3D printing parameters (filling ratio, nozzle diameter, and layer thickness) on the specific surface area, pore characteristics (size and volume), and radial crushing strength of the alumina specimens. The primary and secondary orders of the effects on the radial crushing strength and pore structure were determined through analysis of the experimental data. The experimental results showed that the alumina sample with a filling ratio of 80%, nozzle diameter of 0.6 mm, and layer thickness of 0.3 mm was found to have better strength of 48.07 ± 9.53 N/mm and specific surface area of 185.7315 m2/g. This study provides a theoretical base for the preparation of alumina carriers by DIW 3D printing.