Printing System Research Articles

Energy management system for biological 3D printing based on manifold model morphing and semi-supervised machine learning

This paper focuses on addressing a critical challenge in 3D printing: managing energy consumption. 3D printing has emerged as a transformative technology in manufacturing, but its energy demands are a key concern for cost-effectiveness and sustainability. To tackle this challenge, an energy management system is proposed to leverage manifold model morphing and semi-supervised machine learning, to reduce production costs for 3D printing. The manifold model is a mathematical representation of the 3D object to be printed, and the refinement process involves optimizing the morphing parameters of the manifold model to achieve desired printing outcomes. To enable flexibility in the grasping space, the semi-supervised machine learning is then incorporated to leverage unlabeled data, enhancing the accuracy and robustness of the energy management system. The proposed system addresses the challenges of limited labeled data and complex morphologies of biological products in layered additive manufacturing. The energy management system is more applicable to soft robotics and biomedical products. The performance of the proposed system is evaluated through extensive experiments that demonstrate its effectiveness and efficacy in predicting and managing energy consumption in 3D printing. Our system offers a practical solution for estimating energy consumption in the design stage, and thus guides the designers to adopt the optimal part geometry and process planning for cleaner production. The results highlight that the proposed system is capable of optimizing energy usage in 3D printing, contributing to the advancement of green and sustainable industrial practices.

Trueness of five different 3D printing systems including budget- and professional-grade printers: An In vitro study

ProblemSeveral types of 3D printers with different techniques and prices are available on the market. However, results in the literature are inconsistent, and there is no comprehensive agreement on the accuracy of 3D printers of different price categories for dental applications. AimThis study aimed to investigate the accuracy of five different 3D printing systems, including a comparison of budget- and higher-end 3D printing systems, according to a standardized production and evaluation protocol. Material and methodsA maxillary reference model with prepared teeth was created using 16 half-ball markers with a diameter of 1 mm to facilitate measurements. A reference file was fabricated using five different 3D printers. The printed models were scanned and superimposed onto the original standard tesselation language (.stl) file, and digital measurements were performed to assess the 3-dimensional and linear deviations between the reference and test models. ResultsAfter examining the entire surface of the models, we found that 3D printers using Fused filament fabrication (FFF) technology −120.2 (20.3) μm create models with high trueness but high distortion. Distortions along the z-axis were found to be the highest with the stereolithography (SLA)-type 3D printer at −153.7 (38.7) μm. For the 4-unit FPD, we found 201.9 (41.8) μm deviation with the digital light processing (DLP) printer. The largest deviation (−265.1 (55.4) μm) between the second molars was observed for the DLP printer. Between the incisor and the second molar, the best results were produced by the FFF printer with −30.5 (76.7) μm. ConclusionBudget-friendly 3D printers are comparable to professional-grade printers in terms of precision. In general, the cost of a printing system is not a reliable indicator of its level of accuracy.

Comparison of the Flexural Strength of Three Different Aged and Nonaged 3D-Printed Permanent Crown Resins.

The aim of this study was to evaluate the flexural strength properties of three different aged and nonaged 3D-printed resins built by different 3D printing systems used in dental applications. Bars (2 × 2 × 25 mm) were additively fabricated using a 3D printer and different dental crown resins (Saremco Crowntec, Senertek P-Crown V2, and Senertek P-Crown V3) per the manufacturers' recommendations. Each subgroup was divided into aged and nonaged subgroups (n = 10 bars per group). Thermocycling procedures (5° to 55°C; 5,000 cycles) were performed under favorable conditions for the aged subgroups from each material. Flexural strength (MPa) was measured in all samples using a universal test machine. When both aged and nonaged resins are compared, significant differences were found in flexural strength measurements (P < .001). The highest flexural strength was observed in the Saremco Crowntec group, while the lowest flexural strength was observed in the Senertek P Crown V2 group. The flexural strength measurements of Saremco Crowntec and Senertek P Crown V3 displayed no significant difference between their aged and nonaged groups (P > .05), while Senertek P Crown V2 (P = .039) showed significant differences between its aged and nonaged groups. Saremco Crowntec showed the highest flexural strength both in aged and nonaged groups, while Senertek P Crown V2 had the lowest strength. The artificial aging process decreased flexural strength values in all 3D-printed resin groups.

Towards a locally constructed multi-element ultrasound imaging transducer for resource poor environments

This paper investigates techniques and materials for making a multi-element ultrasound imaging transducer with craft-based techniques available in resource poor environments. The transducer housing can be conveniently divided into three parts: the body supporting the piezoelectric (PZT) elements and other components; the matching layer between the PZT elements and the human body; and the backing layer behind the PZT elements. Low-cost 3D printing systems based on photopolymers were found to be suitable for manufacturing the body. Finite Element Modelling (FEM) showed that the material characteristics of the backing layer and the thickness of the matching layer were much less critical than predicted by ultrasound plane wave theory and transmission line theory, respectively. The backing and matching layers are normally made from epoxy-tungsten composites that are pourable in the uncured state. However, the composite required for the backing layer was putty-like when uncured. When the tungsten was allowed to settle under gravity during curing, a 20 % by volume uncured tungsten-epoxy composite gave a 30 % by volume concentration of tungsten at the bottom when cured at 20–30 °C. These findings, when coupled with the findings from the FEM modelling, suggests that constructing a multi-element ultrasound imaging transducer using craft-based techniques is feasible.

3D-Printable Sustainable Bioplastics from Gluten and Keratin.

Bioplastic films comprising both plant- and animal-derived proteins have the potential to integrate the optimal characteristics inherent to the specific domain, which offers enormous potential to develop polymer alternatives to petroleum-based plastic. Herein, we present a facile strategy to develop hybrid films comprised of both wheat gluten and wool keratin proteins for the first time, employing a ruthenium-based photocrosslinking strategy. This approach addresses the demand for sustainable materials, reducing the environmental impact by using proteins from renewable and biodegradable sources. Gluten film was fabricated from an alcohol-water mixture soluble fraction, largely comprised of gliadin proteins. Co-crosslinking hydrolyzed low-molecular-weight keratin with gluten enhanced its hydrophilic properties and enabled the tuning of its physicochemical properties. Furthermore, the hierarchical structure of the fabricated films was studied using neutron scattering techniques, which revealed the presence of both hydrophobic and hydrophilic nanodomains, gliadin nanoclusters, and interconnected micropores in the matrix. The films exhibited a largely (>40%) β-sheet secondary structure, with diminishing gliadin aggregate intensity and increasing micropore size (from 1.2 to 2.2 µm) with an increase in keratin content. The hybrid films displayed improved molecular chain mobility, as evidenced by the decrease in the glass-transition temperature from ~179.7 °C to ~173.5 °C. Amongst the fabricated films, the G14K6 hybrid sample showed superior water uptake (6.80% after 30 days) compared to the pristine G20 sample (1.04%). The suitability of the developed system for multilayer 3D printing has also been demonstrated, with the 10-layer 3D-printed film exhibiting >92% accuracy, which has the potential for use in packaging, agricultural, and biomedical applications.

Optimization of Pin Type Single Screw Mixer for Fabrication of Functionally Graded Materials

The direct ink writing (DIW) process, used for creating components with functionally graded materials, holds significant promise for advancement in various advanced fields. However, challenges persist in achieving complex gradient variations in small-sized parts. In this study, we have developed a customized pin shape for an active screw mixer using a combination of quadratic B-Spline, the response surface method, and global optimization. This tailored pin design was implemented in a two-material extrusion-based printing system. The primary objective is to facilitate the transformation of material components with shorter transition distances, overcoming size constraints and enhancing both printing flexibility and resolution. Moreover, we characterized the transition delay time for material component changes and the mixing uniformity of the extruded material by constructing a finite element simulation model based on computational fluid dynamics. Additionally, we employed a particle tracking method to obtain the Lyapunov exponent and Poincaré map of the mixing process. We employed these metrics to represent and compare the degree of chaotic mixing and dispersive mixing ability with two other structurally similar mixers. It was found that the optimized pin-type mixer can reduce the transition delay distance by approximately 30% compared to similar structures. Finally, comparative experiments were carried out to verify the printing performance of the optimized pin-type active mixer and the accuracy of the finite element model.

Establishing optimal testing within a quality management system (QMS) for 3D printing in radiotherapy

Establishing optimal testing within a quality management system (QMS) for 3D printing in radiotherapy

Strain/pressure sensors utilizing advanced nanomaterials

AbstractIn this study, the fabrication techniques employed for strain/pressure sensors are covered, highlighting advancements in materials and manufacturing processes. It discusses the use of nanomaterials, such as nanoparticles, nanowires, and graphene to enhance the sensitivity and durability of strain/pressure sensors. Various fabrication methods, including printing, thin‐film deposition, and microelectromechanical systems technologies, are discussed, emphasizing their superiority for strain/pressure sensing applications.

Feasibility of Easy to Use and Inexpensive Three-Dimensional Printed Educational Model of Temporal Bone: Practiced Without Drilling.

Three-dimensional (3D) printed temporal bone model draws great attention as a promising alternative for conventional cadaveric model in education of otologic surgery. However, its high price and requirement for specialized tools hinder widespread use. We devised a simple educational model based on lattice structure to overcome these problems and compared it with a commercial model. We converted high-resolution temporal bone computed tomography images into stereolithography format, and printed it using the G005 3D printing system from CUBICON©. In this process, the part to be drilled out was made of lattice structure. We evaluated the model by a questionnaire prepared in advance, and compared the results with those of a commercial model. We created an educational 3D printed temporal bone lattice model one-tenth the cost of commercial temporal bone. Our model reproduced the important structures of the temporal bone, produced less dust, and had similar strength and grinding sensation compared to the commercial model. The surface texture and reproducibility were comparable to the commercial model. Although most of structures were remodeled more elaborately in the commercial model than our model, our model demonstrated significant potential as a cost-effective educational tool for medical students and residents. 3D printed temporal bone lattice model has potential for widespread use due to low cost and easy accessibility. Further improvements in the fine structures of the temporal bone are necessary to enhance its utility as an educational model.

Methodology for formulating low-carbon printable mortar through particles packing optimization

High packing density is one of the key factors for obtaining ultra-high-performance cementitious materials in the hardened state. Packing density also plays a role in the fresh state, influencing various properties of dense suspensions, including rheological properties and stability, which are highly important in 3d printing applications. The maximum packing density of a specific mixture can be estimated by considering the geometrical properties and proportions of each component using the compressive packing model (CPM). This paper aims to utilize the CPM as an efficient tool for designing cementitious materials specifically tailored for large-scale 3D printing of mortar in bi-component printing systems, with a focus on maximizing the performance-to-environmental impact ratio. Two different sets of mixtures were prepared for this study. Set A consisted of cement, sand, and silica fume, while Set B utilized cement, multiple sands, and multiple limestone fillers. Within each group, various mixtures were tested on a small scale to validate their rheological properties, particularly the yield stress. Pumpability, extrudabilty and buildability were evaluated by utilizing these mixtures in different printing sessions. Additionally, the compressive strengths of these mixtures were characterized. Finally, a method for designing a printable mixture is presented, and efficient and printable formulations with low cement ratio are proposed and printed.

Development of a novel gantry system for cooperative printing of plastic materials

ABSTRACT It is well known that Additive Manufacturing (AM) is a slow process when compared to conventional manufacturing processes. To address this problem, this paper explores the concept of cooperative printing due to its ability to significantly increase the printing speed. It discusses current cooperative printing systems and proposes a new multi-arm configuration to address current limitations such as reduced cooperative printing area. The proposed configuration allows printing parts that are impossible to print or inefficiently printed by other configurations. Moreover, to improve efficiency and reduce printing time, new algorithms are proposed, including the Intermediate Point Method for collision avoidance. This method is three times more effective at preventing collisions compared to the current state-of-the-art algorithms and generates paths with lower travel durations. The proposed system was successfully tested in printing several single and multi-layer objects, showing a significant speed increase, surpassing the maximum printing time reduction reported in the literature.

Thermal imaging-based diagnostic process using explainable artificial intelligence for 3D printing system

Thermal imaging-based diagnostic process using explainable artificial intelligence for 3D printing system

3D printing sequentially strengthening high-strength natural polymer hydrogel bilayer scaffold for cornea regeneration.

3D printing of high-strength natural polymer biodegradable hydrogel scaffolds simultaneously resembling the biomechanics of corneal tissue and facilitating tissue regeneration remains a huge challenge due to the inherent brittleness of natural polymer hydrogels and the demanding requirements of printing. Herein, concentrated aqueous solutions of gelatin and carbohydrazide-modified alginate (Gel/Alg-CDH) are blended to form a natural polymer hydrogel ink, where the hydrazides in Alg-CDH are found to form strong hydrogen bonds with the gelatin. The hydrogen-bonding-strengthened Gel/Alg-CDH hydrogel demonstrates an appropriate thickened viscosity and shear thinning for extrusion printing. The strong hydrogen bonds contribute to remarkably increased mechanical properties of Gel/Alg-CDH hydrogel with a maximum elongation of over 400%. In addition, sequentially Ca2+-physical crosslinking and then moderately chemical crosslinking significantly enhance the mechanical properties of Gel/Alg-CDH hydrogels that ultimately exhibit an intriguing J-shaped stress-strain curve (tensile strength of 1.068 MPa and the toughness of 677.6 kJ/m2). The dually crosslinked Gel-Alg-CDH-Ca2+-EDC hydrogels demonstrate a high transparency, physiological swelling stability and rapid enzymatic degradability, as well as suturability. The growth factor and drug-loaded biomimetic bilayer hydrogel scaffold are customized via a multi-nozzle printing system. This bioactive bilayer hydrogel scaffold considerably promotes regeneration of corneal epithelium and stroma and inhibits cornea scarring in rabbit cornea keratoplasty.

Cloud and online system of 3D printing for serving multi-client of hospitals and medical colleges in different locations

Cloud and online system of 3D printing for serving multi-client of hospitals and medical colleges in different locations

Topology Optimization in 3D Concrete Printing to Reduce Greenhouse Gas Emissions

The construction industry, responsible for 9% of global CO2 emissions and 40% of extracted natural resources, faces the challenge of reducing Greenhouse Gas (CH4, N2O, fuorinated gases, and CO2 dominant in the civil sector) emissions and managing waste sustain-ably. To address these challenges, a digital design for manufacturing methodology is proposed, which combines gradient-based topology optimization (TO) with additive manufacturing (AM) for cementitious structural design, leveraging the advantages of complex and non-traditional optimized forms. The methodology entails initially creating a finite element (FE) simulation for TO to minimize compliance within the three-dimensional design domain, taking into account volume workspace and other AM constraints. Following this, the optimized design is converted into a CAD model, and a CAM script is generated in G-Code language. Subsequently, the design is executed through a 3D Concrete Printing (3DCP) system, thereby integrating CAD-CAE-CAM technologies. The research evaluates the potential for mass reduction through TO structures and carbon dioxide emissions of 3DCP compared to traditional methods, emphasizing the potential of digital fabrication for eco-efficient construction. The observed margin highlights promising opportunities for the optimization and implementation of sustainable practices in the field of civil engineering and construction.

Influence of Carbon Nanotubes on the Mechanical Properties of PLA/MWCNTS Printed Parts in FDM Process

This study systematically and comprehensively investigates the 3D printing process and mechanical properties of PLA/MWCNTS composite material using pneumatic extrusion. Mechanical test specimens were prepared utilizing a pneumatic extrusion 3D printing system, followed by conducting mechanical performance tests. The study focuses on assessing the influence of different material ratios on the strength of these specimens, employing a controlled variable method with varied printing paths. The results demonstrate a significant improvement in the mechanical properties of PLA printed specimens upon the addition of carbon nanotubes, indicating the promising potential of PLA/MWCNTS composite materials as functional materials for FDM technology.

Струмовий режим при електрохімічному 3d-друці виробів із міді

The peculiarities of the use of copper nitrate electrolytes in local electrodeposition or electrochemical 3D printing systems have been studied. A model of the current mode in electrochemical 3D printing has been proposed. The possibility of obtaining electrochemically 3D printed objects with a profile height up to 100 μm with a compact fine-crystalline metal structure at a current density of 2 A/dm2 in a copper nitrate electrolyte with a content of 300 g/l and with the simultaneous introduction of gloss-forming additives of the Rubin complex (KIESOW OBERFLÄCHENCHEMIE GmbH &amp; Co) and glycine is shown.

Comparative Life Cycle Assessment of molding process and 3D printing of High-Performance Long-fiber Reinforced Composites

Composite materials are widely employed to produce high-performance components. However, their usage is associated with significant environmental impacts, deriving from the constituent materials (e.g., carbon fiber and epoxy resin) and the manufacturing process. Traditional methods of composite manufacturing such as bag molding or compression molding were subjected to discussion due to their high energy requirements, related to the required heat and pressure, the use of molds and the production of composite scraps. In contrast, 3D printing presents a promising alternative, that could reduce material waste and energy consumption.This study investigates an innovative 3D printing process for high-performance composites, in particular continuous carbon fiber and thermosetting epoxy matrix, with the aim of investigating its environmental impact.A comprehensive Life Cycle Assessment (LCA) was conducted to compare the environmental footprints of traditional molding and 3D printing processes of continuous fiber composites. A wide range of factors such as energy consumption, resource utilization, greenhouse gas emissions, and waste generation was considered.The outcomes of this comparative LCA reveal a significant reduction in environmental impacts associated with the innovative 3D printing system with respect to traditional methods. These findings offer crucial insights into the sustainability of 3D printing for high-performance composites, providing a valuable decision-making tool for industries seeking eco-friendly manufacturing solutions.

EVALUATION OF CEMENT GAP OF INLAY RESTORATIONS FABRICATED USİNG A 3D PRINTING SYSTEM

Bu çalışmanın hedefi, üç boyutlu (3B) yazıcı sistemi kullanılarak üretilen inley restorasyonlarının siman aralığı değerlerini araştırmaktır.Bu çalışma kapsamında, toplamda 60 adet typodont diş kullanıldı. Bu dişlerin yarısı (n=15), mesio-oklüzal (MO) kaviteler için, kalan yarısı (n=15) ise mesio-oklüzal-distal (MOD) kaviteler oluşturmak için kullanıldı. Bukkolingual genişlik 2,5-3mm ve pulpal derinlik 2mm olacak şekilde okluzal kaviteler hazırlandı. Proksimal inley kaviteler, basamak derinliği 1,5mm ve basamak kalınlığı 1 mm, bukkolingual genişliği 5 mm olarak tasarlandı. Kaviteler, intraoral dijital tarayıcı (TRIOS 3 Basic, Kopenhag, Danimarka) kullanılarak tarandı ve EXOCAD (Exocad Dental CAD 2.2, Darmstadt, Almanya) yazılımıyla inley restorasyon tasarımları yapıldı. 3B yazıcı (Phrozen sonic mini 4K SLA cihazı, Hsinchu, Tayvan) ile restorasyonların üretimi yapıldı. Restorasyonların siman aralığı değerlendirmek için silikon replika yöntemi kullanıldı ve kesitler stereomikroskop altında x10 büyütmede incelendi. Ölçümler üç farklı noktadan yapılıp, analiz için Adobe Photoshop programı kullanıldı. SPSS 22.0 programında Pairwise-Comparisons ve Kruskal-Wallis testleri ile verilerin analizi yapıldı (α

Development of a Textile Dyeing Fabric Printing System Simulator and Research for Local Production of Servo System

Development of a Textile Dyeing Fabric Printing System Simulator and Research for Local Production of Servo System