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Additive Manufacturing (AM) has emerged as an important digital technology in improving production efficiency by analysing possible environmental impacts of the operations. Therefore, this study aims to investigate the impacts of redesigned products for transition to AM on sustainable production processes. In this study, an industrial-scale product was redesigned according to AM principles and manufactured using the Fused Deposition Modelling (FDM) technique. The environmental impacts of the production methods were evaluated in terms of material consumption and carbon dioxide (CO2) emissions using the Life Cycle Assessment (LCA) method. Thus, according to LCA results, the use of a single type of material and production method for the redesigned product, as well as reducing the amount of material used by eliminating the fasteners, resulted in a 60.45% reduction in material consumption and 85.59% reduction in CO2 emissions compared to CM. Although the production time in CM is shorter than FDM, the necessity of a mould design and manufacture by pre-processing resulted in an increase in delivery time. Results show that the material unit costs for both manufacturing methods are very similar. This study provides various implications that create sustainable development in the manufacturing industry for the transition to AM. ABBREVIATIONS: AM, Additive Manufacturing; CAD, Computer-Aided Design; CAE, Computed-Aided Engineering; CM, Conventional Manufacturing; CNC, Computer Numerical Control; CO2, Carbon Dioxide; DFAM, Design for Additive Manufacturing; DIY, Do It Yourself; FDM, Fused Deposition Modelling; LCA, Life Cycle Assessment; LEM, Laser Engraving Machine; PLA, Polylactic Acid; SLA – Stereolithography; SLS, Selective Laser Sintering; 3D – Three Dimensional [ABSTRACT FROM AUTHOR]

The printing accuracy in ceramic stereolithography is deteriorated by shrinkage due to photopolymerization of monomers and broadening owing to scattering of light. To improve the accuracy of printed alumina parts, a series of experiments involving the reduce of shrinkage and broadening were conducted. Firstly, the dependence of conversion of monomers, shrinkage of suspensions and warpage of parts on energy doses was quantitively investigated and correlated, with which the shrinkage was well controlled through optimization. Besides, the warpage problem was effectively resolved when adding 30 wt% PEG-200 in the suspensions to release the accumulated internal stress. Next, the broadening under different energy doses was observed and reduced by addition of absorbers, after which a self-defined parameter C d / W e was applied to suggest strategies in the selection of appropriate processing parameters and absorber content. On this basis, the holes with a diameter ranging from 50–200 μm were successfully printed. [ABSTRACT FROM AUTHOR]

The modern additive manufacturing process enables the fabrication of innovative structural designs of lattice structures with enhanced mechanical properties. Characterizing the designability of lattice geometries and the corresponding mechanical performance, particularly the compressive strength is vital to commercializing lattice structures for lightweight components. In this paper, a Novel hybrid type of lattice structure was developed inspired by the overlapping pattern of scales on dermal layers of the species like fish and circular patterns observed from the bamboo tree structure. This research designed the lattice cell with 20%,30%,40%, and 50% overlapping areas based on the proposed circular area. The unit cell wall thickness varies between 0.4 mm and 0.6 mm. The designed structures with a constant volume of 40x40x40 mm, varied circular diameters, overlapping areas, and unit wall thickness are modeled in Fusion 360 software. 3D-printed lattice structures were fabricated using the vat polymerization type three-dimensional printing machine using the principle of stereolithography (SLA) technique. Then, the 3D-printed specimens are tested for quasi-static compressive response in a universal testing machine (UTM) by following ASTM standards. The test results are evaluated and compared with the simulation results. Finally, the best lattice structure is selected for energy absorption application in the aerospace and defense sectors. [ABSTRACT FROM AUTHOR]

Reconstruction in cases of osteoporosis or accidents often requires the use of synthetic bones or scaffolds, with hydroxyapatite standing out as a preferred material due to its biocompatibility. This study focuses on the production and characterization of hydroxyapatite-coated 3D-printed bone scaffolds. The 3D-printed structures were fabricated by blending hydroxyapatite powder, synthesized through the solution combustion technique, with a liquid photopolymer, followed by exposure to UV irradiation. The resulting hydroxyapatite/photopolymer scaffolds were characterized by a uniform distribution of fine hydroxyapatite powder on the surface. Subsequently, these scaffolds underwent coating with a hydroxyapatite slurry, experimenting with various coating and sintering conditions. Despite the decomposition of the photopolymer during the sintering process, the coated scaffold displayed an increased thickness of the infill line within the pattern, resulting in reduced void size and enhanced compressive strength. Weibull analysis of the compressive strength indicated a high likelihood of survival at 4 MPa, falling within the acceptable range for cancellous bone strength. This comprehensive study showcased the potential of hydroxyapatite-coated 3D-printed bone scaffolds with a favorable microstructure and mechanical strength, making them promising for applications in bone reconstruction. [ABSTRACT FROM AUTHOR]

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Recent progress in additive manufacturing has enabled the application of stereolithography (SLA) in bioprinting to produce 3D biomimetic structures. Bioinks for SLA often require synthetic polymers as supplements to ensure the structural integrity of the printed cell‐laden constructs. High molecular weight (MW) poly(ethylene‐glycol)‐diacrylate (PEGDA) (MW ≥ 3400 Da) is commonly used to enhance the mechanical property of crosslinked hydrogels. However, the production of bioink with high MW PEGDA requires in‐house polymer synthesis or the acquisition of costly reagents, which may not be readily available in all laboratory settings. As an alternative to high MW PEGDA, this research investigated the use of poly(ethylene‐glycol)‐dimethacrylate (PEGDMA) (MW = 1000 Da) as a supplement of a bioink to enhance the mechanical properties of the SLA‐printed constructs. The successful demonstration showcases 1) the fabrication of 3D constructs with overhang and complex architecture, and 2) the cytocompatibility, with high cell viability of 71–87% over 6 days of culture, of the GelMA‐PEGDMA bioink to enable cell‐laden bioprinting. This study suggests PEGDMA as a viable supplement in the formulation of SLA bioink. The accessibility to PEGDMA will facilitate the advance in 3D bioprinting to fabricate complex bioinspired structures and tissue surrogates for biomedical applications. [ABSTRACT FROM AUTHOR]

The remediation of polluted water is a major concern for public health and the environment. Catalytic removal of model organic and inorganic pollutants in water using carbon catalysts has shown promising results. In the present work, stereolithographically 3D‐printed bio‐based carbon monoliths with different textural and surface chemistry properties were used as catalysts for oxalic acid oxidation and catalyst supports for bromate reduction in continuous systems. A significant synergistic effect between ozone or dihydrogen and carbon catalyst was evidenced by mineralization of 14–25 % of oxalic acid or reduction of 15–45 % of bromates in the steady state, respectively. The best results were achieved with samples with the highest mesoporous surface area or, in the case of lower surface area, with samples having the strongest basic character. As materials with great potential, optimizing the textural properties of architected carbon monoliths will enable them to compete with other macro‐structured carbon catalysts. [ABSTRACT FROM AUTHOR]

This study proposes porous block structures as a viable alternative to conventional pebble bed structures, aiming to overcome the structural drawbacks including low packing fractions, extensive stress concentrations, and low thermal conductivity. To validate the feasibility of the porous block structures, Gyroid Li 2 TiO 3 block breeders were prepared by the hybrid process of stereolithography and gelcasting. The resulting Gyroid Li 2 TiO 3 block breeders, measuring ∼18.8 × 18.8 × 18.8 mm3, achieved a high packing fraction of ∼78.8% through optimized slurry and sintering at 1100 °C for 3 h. These Gyroid Li 2 TiO 3 block breeders exhibited clear contours, integrated channels, a compressive strength of 8.78 MPa, and a low isotropic sintering shrinkage of ∼6%. The hybrid process demonstrated enormous advantages over the reported 3D printing for the preparation of porous block breeders with low shrinkage and large-sized dimensions. This study offers an effective avenue for the manufacture of porous block breeders with tunable tritium-releasing channels and large-sized configurations. [ABSTRACT FROM AUTHOR]

Microneedles offer a promising avenue for painless drug delivery through micro‐perforation, and additive manufacturing, particularly stereolithography, has proven effective for their fabrication. This study focuses on developing a novel biocompatible resin for 3D printing microneedles. Spectroscopic methods are employed to confirm the structures of all intended resin monomers, with a specific analysis of the crystallographic structure of cyclohexanedimethanol methacrylate (CDMM) using x‐ray diffraction. The results indicate that CDMM crystallizes in the monoclinic system, aligning with the P21/c space group. The fabricated conical microneedles, standing at approximately 655 μm in height, underwent thorough mechanical and thermal characterization. Depth analyses of micro‐perforations in Parafilm M and pig skin were performed using optical coherence tomography and histological sections, demonstrating successful penetration through the stratum corneum and epidermal layers into the superficial dermal layer (1.5–4 mm thickness) without affecting nerve endings. Cytocompatibility tests affirm the biocompatibility of the microneedles. This work highlights the potential of the newly developed biocompatible material for printable drug delivery systems, emphasizing microneedles and other implant forms. [ABSTRACT FROM AUTHOR]

Modern polymer‐based technical components not only have to fulfill demanding mechanical‐structural properties but need to integrate different functions to yield hybrid systems for complex operations. Typically, neither materials nor processing technologies are fully compatible with each other. The aim of the work is to combine the advantages of seemingly incompatible manufacturing processes such as high‐volume injection molding (IM) and precision additive manufacturing to produce functional and customized hybrid materials. IM is widely used for polymer processing but stands against high investment costs for tailor‐made molds with high‐resolution features. They focus on overprinting of injection‐molded parts made of thermoplastic polyurethane (TPU) with microstructures via projection‐microstereolithography (PµSL) to generate hybrid polymer materials with spatially tailored stiffness, enabling selective reinforcement, resulting in an E modulus increase of 195% compared to mere IM‐processed TPU. With that, the hybridization of processing methods is showcased to extend the product properties of polymer materials obtained via either IM or PµSL printing that have, prospectively, a maximum degree of individualization as well as a multitude of structural and functional features at the same time. To achieve optimum interfacial adhesion, the influence of surface roughness is studied, and reinforcement effects of different overprinted microstructure types are evaluated. [ABSTRACT FROM AUTHOR]

Highlights This review paper delves into the manufacturing methods, material properties, and applications of polymer‐based composites in the field of advanced manufacturing, offering a detailed explanation of their production through various additive manufacturing (AM) techniques and their diverse applications across multiple industries. Polymer‐based composite materials have emerged as crucial elements in AM due to their enhanced properties and design versatility, enabling the creation of components with unprecedented performance characteristics. The paper comprehensively covers the major AM methods employed for composite materials, including fused filament fabrication, Digital Light Processing/Stereolithography, Direct Ink Writing, and Selective Laser Sintering. Each of these methods is explored in terms of its mechanism, suitability for different composite materials, and the resulting material properties. The review also provides an insightful analysis of how these AM techniques are revolutionizing industries such as soft robotics, mechanical, electrical, and biomedical fields. The paper concludes by discussing the current challenges in this domain and projecting future trends in the development and application of composite materials in advanced manufacturing. This review aims to offer a comprehensive resource for researchers and practitioners in the field, highlighting the transformative impact of polymer‐based composites in AM and their growing significance across various sectors. Comprehensive review and classification of novelties in printing method for polymer based composite material manufacturing. Introduces innovative techniques to create and enhance material properties of composites. Explores interdisciplinary applications in biomedical, electronics, and sensors, demonstrating material versatility. Provides a systematic correlation between manufacturing method, material properties, and applications of novel polymer‐based composites. [ABSTRACT FROM AUTHOR]

Buccal cavernous hemangiomas are uncommon vascular lesions, particularly in adult patients. We present a case of a 23-year-old male with a progressive left cheek swelling over three years. Clinical examination and radiographic imaging revealed a solid, multilobulated mass in the left buccal and masticator spaces. Surgical excision was performed, and histopathological analysis confirmed the diagnosis of a cavernous hemangioma. This case underscores the importance of recognizing and appropriately managing rare vascular lesions in adult patients. [ABSTRACT FROM AUTHOR]

We used stereolithography to print polymer nanocomposite samples of stimuli-responsive spin crossover materials in the commercial photo-curable printing resins DS3000 and PEGDA-250. The thermomechanical analysis of the SLA-printed objects revealed not only the expected reinforcement of the polymer resins by the introduction of the stiffer SCO particles, but also a significant mechanical damping, as well as a sizeable linear strain around the spin transition temperatures. For the highest accessible loads (ca. 13–15 vol.%) we measured transformation strains in the range of 1.2–1.5%, giving rise to peaks in the coefficient of thermal expansion as high as 10−3 °C−1, which was exploited in 3D printed bilayer actuators to produce bending movement. The results pave the way for integrating these advanced stimuli-responsive composites into mechanical actuators and 4D printing applications. [ABSTRACT FROM AUTHOR]

This study presents a short overview of the main 3D polymer composite items that are fabricated by extrusion and stereolithography printing. By coupling polymers traditionally used in additive manufacturing, such as PEGDA, and polymers of biomedical interest, such as PVA, with carbon nanostructures, such as nanodiamond and graphene nanoplates, and conductive polymers, such as PEDOT and PANI, it has been possible to produce objects with specific functional properties exploited for fabricating scaffolds for cell growth and proliferation as well as soft electrodes for developing organic compounds sensing devices and electrocardiogram monitoring systems under real‐time conditions. [ABSTRACT FROM AUTHOR]

The present study is dedicated to the manufacturing of highly porous triply periodic minimal surface (TPMS) constructs, fabricated from recycled end of life borosilicate pharmaceutical glass employing masked stereolithography. The structures were prepared from a simple blend of photocurable resin with glass powder (<38 µm). The gyroid model was selected with the porosity varying from 75 to 90%. Hot stage microscopy was applied to examine the glass sintering behaviour to improve the translucency of the 3D scaffolds. The obtained 3D scaffolds were dip-coated with TiO 2 and further utilized for the photocatalytic degradation of dyes. The photocatalytic efficiency of the 3D scaffolds was evaluated by the degradation of methylene blue in water. It was found that 3D scaffolds coated with TiO 2 showed a 40% higher degradation rate in comparison to bare 3D scaffolds under UV irradiation, which determines the significant role of TiO 2 in the organic dye degradation. The better efficiency of 3D scaffolds coated with TiO 2 , compared with uncoated BSG 3D scaffolds is attributed to a better recombination rate, and the migration of electrons to the surface of the scaffold, where the charges participate in the photodecomposition of MB dye. The efficiency of the scaffolds was assessed for five consecutive cycles. The degradation efficiency after the fifth cycle was 75%, confirming the stability of the system. [ABSTRACT FROM AUTHOR]

The pyramid lattice sandwich structure, characterized by high load‐bearing capacity, lightweight nature, and fully open internal space, is considered an extremely promising super‐strong structure. Stereolithography technology was utilized to achieve the monolithic formation of single‐layer multi‐cell pyramidal lattice sandwich structures. Quasi‐static compression tests and finite element simulations were conducted to characterize the compressive properties and failure modes. Results indicate that the compressive strength, compressive modulus, specific strength, and specific stiffness of the single‐layer multi‐cell pyramidal lattice sandwich structure increase as the relative density increases. Moreover, fracture failure was observed in the structures with various relative densities. Additionally, the compressive failure of multi‐layer density gradient pyramidal lattice sandwich structures was investigated. Experimental and numerical findings indicate that the optimal density gradient scheme for the ZCMLG structure is I‐III‐II, resulting in a peak compression force that is 342.14% and 288.55% higher than that of the ZAMLG and ZBMLG structures, respectively. Highlights: The mechanical properties and failure modes of the lattice structure are investigated.The effect of density gradients on lattice structure failure modes is investigated.The failure mode of the lattice structure is verified by finite element simulation. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive analysis of the utilization of 3D printing technology for the fabrication of ceramic shells in the context of investment casting. This study encompasses an exploration of various 3D printing techniques such as binder jetting technology and lithography-based ceramic manufacturing applied to ceramic materials tailored for investment casting applications for different materials. Comparative analyses between conventionally manufactured shells and those produced through 3D printing techniques are presented, shedding light on the potential advantages and challenges associated with the adoption of additive manufacturing in investment casting processes. The findings of this study reveal that both methods offer viable solutions for creating ceramic materials suitable as shells for investment casting. Both lithography-based ceramic manufacturing and binder jetting technology exhibit unique advantages and challenges. Lithography-based ceramic manufacturing demonstrates a superior surface finish and resolution, making it particularly suitable for intricate designs and fine details. On the other hand, binder jetting technology presents advantages in terms of speed and scalability, allowing for the rapid production of larger components. [ABSTRACT FROM AUTHOR]

3D printing (3DP) is increasingly utilized to achieve quick turnaround on various geometric designs and prototypes, being the growing part of additive manufacturing technology (AMT). The 3DP technique effectively improves the production of complex models in terms of low-cost, time-consuming production, and with less material volume. The key to results optimisation with 3DP is the preparation of the geometry. The following techniques can effectively reduce the required time of the 3D printing process for complex and non-linear CAD files. The fused deposition modelling/fabrication (FDM/FFF) techniques become the first choice in many applications, including biomedical ones. Still, some obstacles exist in the geometry roughness and quality zones. This paper proposes an optimisation method for 3D printed shapes used in biomedical devices and instrumentation by minimising the support structure attached to the model using the FDM technique. In this research, we proposed a method for dynamic compensation against gravity-affected parts extended from the main object's geometry using a forward planar learning (FPL) algorithm to minimise cusp height in 3D printed objects. After the slicing stage, the outcomes proved to be of good quality, optimised the object's surfaces, and minimised the printing time by 32%-38%. The proposed method is promising in defining a better setting for slicing and toolpath for FDM 3D printing. However, this method was not tested on other 3DP methods (Stereolithography (SLA), Selective laser sintering (SLS), and Digital Light Processing (DLP)), as more verification efforts need to be done on these 3D printing processes. [ABSTRACT FROM AUTHOR]

Purpose: This in vitro study aimed to create a graded structured dental crown using 3D printing technology and investigate the fracture resistance and the adaptation of this new design. Materials and Methods: A dental crown with a uniform thickness of 1.5 mm was designed, and the exported stereolithography file (STL) was used to manufacture 30 crowns in three groups (n = 10), solid (SC), bilayer (BL), and multilayer (ML) crowns using 3D jet printing technology. Marginal and internal gaps were measured using the silicone replica technique. Crowns were then luted to a resin die using a temporary luting agent and the fracture resistance was measured using a universal testing machine. One‐way ANOVA and Tukey post hoc tests were used to compare the fracture resistance and the adaptation of crowns at a significance level of 0.05. Results: Mean marginal and internal gap of the ML group were 80 and 82 mm, respectively; which were significantly (p < 0.05) smaller than BL (203 and 183 mm) and SC (318 and 221 mm) groups. The SC group showed the highest mean load at fracture (2330 N) which was significantly (p < 0.05) higher than the BL (1716 N) and ML (1516 N) groups. Conclusion: 3D jet printing technology provides an opportunity to manufacture crowns in a graded structure with various mechanical properties. This study provided an example of graded structured crowns and presented their fracture resistance. SC group had the highest fracture resistance; however, ML had the best marginal and internal adaptation. [ABSTRACT FROM AUTHOR]

Background: The use of polymer bearings in some industries has increased in recent years because of their advantages, such as resistance to dirt and dust, no need for maintenance and lubrication, and chemical resistance, especially in hygienic areas. Additive manufacturing (AD) or 3D printing is also a popular method that makes complex geometric shapes easily produced using polymer material, layer by layer, of the defined component. Purpose: The study aims to investigate the applicability of producing polymer ball bearing with additive manufacturing techniques by experimentally observing the bearing's vibrations, temperature, and rolling resistance. Methods: A set of ball-bearing races—inner and outer—are produced with the stereolithography (SLA) method using polymeric resin and tested under a certain load. Results: Vibrations and load cell data for rolling resistance are analyzed through its lifetime to investigate the evolution of the bearing under the test. Conclusion: The additive manufacturing method could be preferred to produce a ball bearing with limited life. [ABSTRACT FROM AUTHOR]

Additive manufacturing is the state‐of‐the‐art method for producing complex ceramic parts. For cellular materials, the freedom of design is particularly advantageous, as pore networks and shapes can be tailored. Herein, the direct printing of complex parts with high porosity using the cost‐effective manufacturing method of Liquid Crystal Display‐based stereolithography on low‐cost printers is determined. It is investigated how the architecture of the alumina Kelvin cells topology, their fabrication process, the printing parameters, and the microstructure affect the accuracy and mechanical properties of the printed samples. A notable reduction to a strut thickness of Kelvin cells down to 0.20 mm is achieved corresponding to a reduction of 1.5 compared with the state‐of‐the‐art literature (min. 0.35 mm). Ultrahigh porosities between 89.5% and 97.2% and a maximum compressive strength of 1.84 ± 0.17 MPa are reached due to the dense struts of the structure. Low‐cost and simple vat ceramic photopolymerization with high accuracy printing proves to be a promising candidate for the rapid and cost‐effective fabrication of highly porous and complex ceramic structures. [ABSTRACT FROM AUTHOR]

Two‐photon lithography is considered a promising technology because it can achieve high resolution up to scale of 100 nm among additional processing technologies; further, it can be used to fabricate nano‐/microstructures. However, it requires an unrealistic long time to obtain a practical model that is close to the human organ diameter in the order of millimeters. In this study, an in‐process‐resolution‐tunable (iPRT) stereolithography system is reported, that realizes an optimal laser processing pathway using a new algorithm that automatically generates the processing pathway obtained by dividing the fabrication area by the effect of microstructure disappearance during the surface offset. It is demonstrated that the aforementioned algorithm can produce structures up to 50 times faster than the conventional methods and can be applied to cell culture scaffold for regenerative medicine. [ABSTRACT FROM AUTHOR]

Microfluidic devices have immense potential for widespread community use, but a current bottleneck is the transition from research prototyping into mass production because the gold standard prototyping strategy is too costly and labor intensive when scaling up fabrication throughput. For increased throughput, it is common to mold devices out of thermoplastics due to low per-unit costs at high volumes. However, conventional fabrication methods have high upfront development expenses with slow mold fabrication methods that limit the speed of design evolution for expedited marketability. To overcome this limitation, we propose a rapid prototyping protocol to fabricate thermoplastic devices from a stereolithography (SLA) 3D printed template through intermediate steps akin to those employed in soft lithography. We apply this process towards the design of self-operating capillaric circuits, well suited for deployment as low-cost decentralized assays. Rapid development of these geometry- and material-dependent devices benefits from prototyping with thermoplastics. We validated the constructed capillaric circuits by performing an autonomous, pre-programmed, bead-based immunofluorescent assay for protein quantification. Overall, this prototyping method provides a valuable means for quickly iterating and refining microfluidic devices, paving the way for future scaling of production. [ABSTRACT FROM AUTHOR]

Photopolymerization‐based ceramic 3D printing, known as digital light processing (DLP), offers a valuable platform for rapidly prototyping previously unattainable intricate architectures without the need for additional molds. However, the presence of ceramic particles in photocurable suspensions introduces challenges, including elevated viscosity and diminished curing depth due to light‐ceramic particle interactions. This ultimately compromises the efficacy of the photocuring process, resulting in undesirable geometric inaccuracies. In this study, meticulously engineered lead‐free ferroelectric barium titanate (BaTiO3, BTO) ceramic granules, produced through a spray‐drying process, optimize ceramic suspension formulation. This approach enhances ceramic flowability and involves the judicious addition of a binder, yielding a uniform redispersion of ceramic particles within the matrix, while maintaining a bimodal particle size distribution with reduced diameters. Supported by both experimental and numerical simulations, this improves the rheological and curing properties, enabling the successful fabrication of highly dense, complex 3D‐printed BTO structures with excellent shape fidelity. Moreover, by carefully designing the thermal profiles, DLP 3D‐printed BTO ceramics exhibit impressive shape retention after debinding and sintering while demonstrating ferroelectric and dielectric performances comparable to their non‐3D‐printed counterparts. This study presents a transformative approach that unlocks the full potential of ceramic 3D DLP printing. [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal "Lab on a Chip," which focuses on devices and applications at the micro- and nanoscale. It includes a range of articles on various topics, such as periodontal disease diagnosis, tissue barrier function, nucleic acid detection, cardiac muscle rings, and more. The journal aims to connect the world with the chemical sciences and is published by The Royal Society of Chemistry. [Extracted from the article]

Stereolithography 3D printing, although an increasingly used fabrication method for microfluidic chips, has the main disadvantage of producing monolithic chips in a single material. We propose to incorporate during printing various objects using a "print-pause-print" strategy. Here, we demonstrate that this novel approach can be used to incorporate glass slides, hydrosoluble films, paper pads, steel balls, elastic or nanoporous membranes and silicon-based microdevices, in order to add microfluidic functionalities as diverse as valves, fluidic diodes, shallow chambers, imaging windows for bacteria tracking, storage of reagents, blue energy harvesting or filters for cell capture and culture. [ABSTRACT FROM AUTHOR]

Purpose: Hepatocellular carcinoma (HCC) is one of the most common types of liver cancer that could potentially be surrounded by healthy arteries or veins that a surgeon would have to avoid during treatment. A realistic 3D liver model is an unmet need for HCC preoperative planning. Methods: This paper presents a method to create a soft phantom model of the human liver with the help of a 3D-printed mold, silicone, ballistic gel, and a blender. Results: For silicone, the elastic modulus of seven different ratios of base silicone and silicone hardener are tested; while for ballistic gel, a model using 20% gelatin and 10% gelatin is created for the tumor and the rest of the liver, respectively. It is found that the silicone modulus of elasticity matches with the real liver modulus of elasticity. It is also found that the 10% gelatin part of the ballistic gel model is an excellent emulation of a healthy human liver. Conclusion: The 3D flexible liver phantom made from a 10% gelatin-to-water mixture demonstrates decent fidelity to real liver tissue in terms of texture and elasticity. It holds significant potential for improving medical training, preoperative planning, and surgical research. We believe that continued development and validation of such models could further enhance their utility and impact in the field of hepatobiliary treatment planning and education. [ABSTRACT FROM AUTHOR]

The customized processing of polymer materials in the microscale by high‐resolution 3D printing provides an easy access to advanced applications in the fields of optics, microfluidics, tissue engineering, and life science. However, the 3D printing of enclosed structures in the scale of tens of microns such as closed microfluidic channels remains a challenge as channel structures often are clogged by residual cured resin. Dual‐curing systems based on off‐stoichiometric thiol‐ene and thiol‐ene/epoxy chemistry are well‐known for adhesive‐free bonding in the fabrication of cast or injection molded microfluidic devices. Herein, the first high‐resolution stereolithography 3D printing of a dual‐curing thiol‐ene/epoxy system in the microscale for the fabrication of customized microfluidic devices is presented. In the first curing step, by high‐resolution 3D printing open microfluidic structures are produced. Consecutively, the microchannels are sealed by adhesive‐free dry bonding upon thermal initiation, producing well‐controlled structures with channel sizes down to 80 µm. Before bonding, the intermediate material allows for tailored surface modification with biotin, which allows for consecutive immobilization of various biomolecules. A DNA‐bioassay with specific patterning is shown in the sealed chip. The presented work paves the way toward the fabrication of customized microfluidic devices for a large range of specific bioassays. [ABSTRACT FROM AUTHOR]

Even in digital workflows, models are required for fitting during the fabrication of dental prostheses. This study examined the influence of different parameters on the dimensional accuracy of three-dimensionally printed models. A stereolithographic data record was generated from a master model (SOLL). With digital light processing (DLP) and stereolithography (SLA) printing systems, 126 models were produced in several printing runs—SolFlex350 (S) (DLP, n = 24), CaraPrint 4.0 (C) (DLP, n = 48) and Form2 (F) (SLA, n = 54)—and their accuracy was compared with plaster and milled polyurethane models. In addition to the positioning on the build platform, a distinction was made between parallel and across arrangement of the models to the printer's front, solid and hollow models, and printing with and without support structures. For accuracy assessment, five measurement sections were defined on the model (A–E) and measured using a calibrated digital calliper and digital scans in combination with the GOM Inspect Professional software 2021. The mean deviation between the measurement methods for all distances was 79 µm. The mean deviation of the models from the digital SOLL model were 207.1 µm for the S series, 25.1 µm for the C series and 141.8 µm for the F series. While positioning did not have an influence, there were clinically relevant differences mainly regarding the choice of printer, but also individually in alignment, model structure and support structures. [ABSTRACT FROM AUTHOR]

The typical high-density zirconium carbide (ZrC) ceramic requires high temperature and high pressure, leading to high manufacturing cost for complex shapes. Herein, nano-sized carbon layer encapsulated ZrC particles were pressureless sintered to achieve near-net preparation of high-density and complex-shape ZrC ceramic. The results indicate that reaction between carbon layer and the ZrC x O y phase in ZrC was improved because the carbon layer shortened the oxygen diffusion pathway. The oxygen content decreased from 3.52 wt% to 0.82 wt% while the thickness of carbon layer decreased from 4.0 nm to 0.75 nm after sintering at 1950 °C for 1 h. Furthermore, the migration of oxygen from ZrC x O y phase to the carbon layer effectively facilitate the formation and growth of the sintering neck. The resulting ZrC ceramic exhibited a high relative density of 92.3 % and excellent mechanical properties. The Vickers hardness, indentation fracture toughness, micro hardness, elastic modulus, and flexural strength were 17.3 ± 0.7 GPa, 4.0 ± 0.5 MPa m1/2, 22.2 ± 2.4 GPa, 429.9 ± 20.7 GPa, and 324 ± 8 MPa, respectively. This work provides a novel perspective to fabricate near-net, high-density and complex-shape ZrC ceramic at lower temperature without pressure. [ABSTRACT FROM AUTHOR]

Complex Silicon carbide (SiC) structures are hardly achievable via traditional manufacturing methods, while stereolithography 3D printing technology effectively shapes sophisticated structures with high precision. However, it is a huge challenge to prepare SiC slurry for stereolithography 3D printing with excellent curing ability due to the increased light absorption of SiC powder. Therefore, a novel approach to fabricating high-purity SiC structures is proposed in this study based on the stereolithography 3D printing process, where SiO 2 powder is used as an additive to increase the curing thickness from 27.8 μm to 53.0 μm. Moreover, phenolic epoxy resin (PEA) is introduced as a carbon source to transform SiO 2 to SiC during sintering. As a result, there is almost no SiO 2 phase or SiOC remaining in the final parts when the addition of PEA reaches 50 wt% related to the resin weight after sintering at 1600 °C for 4 h. Based on the SiC/SiO 2 /PEA slurry systems prepared, high-purity silicon carbide with complex structures can be successfully fabricated in one step without any pre-oxidation or precursor impregnation processes. This approach provides valuable insights into additive manufacturing of high-purity complex SiC structures. [ABSTRACT FROM AUTHOR]

The adoption of three-dimensional (3D) imaging technologies in orthognathic surgery led to the development of virtual surgical planning and printing of patient-specific orthognathic surgical splints (OSSs). The accuracy and precision of 3D printed OSSs are considered important; however, there is limited data in the literature regarding whether the type of resin materials may influence these measures. A virtual OSS was created using a set of typodont models and printed in Biomed Clear, Dental LT V2, and Surgical Guide resins (Formlabs, Somerville, MA, USA), using a stereolithography printer. The upper intercanine width, intermolar width, and arch length were analysed. Differences between the reference dimensions of the virtual splint and the corresponding mean measurements of the 3D-printed splints were mostly considered clinically acceptable. The greatest variation was observed in the arch length for all 3 materials, which relates to the Z-axis of the printer; only 33.3–66.7% of OSSs were within the tolerance limit of ±0.1 mm quoted by the manufacturer. The Surgical Guide group demonstrated the highest degree of accuracy and precision overall. Further research would help to assess the 3D accuracy and precision, explore the variation found between different resin materials used, and confirm the findings of this research. [ABSTRACT FROM AUTHOR]

The constant improvement of stereolithography (SL) in terms of achievable resolution and printing time has sparked high expectations that SL will enable the rapid prototyping of truly microfluidic chips with features below 100 µm. However, most commercial high‐resolution stereolithography devices are based on Digital Light Processing (DLP) and thus sacrifice lateral printing size for resolution. Consequently, even 10 years after the advent of microstereolithography there is no commercialized 3D printing system that can effectively fulfill all the demands to replace soft lithography for microfluidic prototyping. In this work, for the first time, This study demonstrates that a commercial laser‐based stereolithography device is capable of manufacturing microfluidic chips with embedded channels smaller than 100 µm with a footprint of 7.24 × 0.3 cm2. A chip fabricated in poly(ethylene glycol) diacrylate (PEGDA) that can readily be used for fluid mixing, is presented in this study. This research shows that the accessibility of high‐resolution chips with footprints of several cm2, using laser‐based stereolithography, enables the manufacturing of truly microfluidic systems with high impact on prototyping and manufacturing. [ABSTRACT FROM AUTHOR]

This study proposes a modularized soft robotic arm with integrated sensing of human touches for physical human–robot interactions. The proposed robotic arm is constructed by connecting multiple soft manipulator modules, each of which consists of three bellow-type soft actuators, pneumatic valves, and an on-board sensing and control circuit. By employing stereolithography three-dimensional (3D) printing technique, the bellow actuator is capable of incorporating embedded organogel channels in the thin wall of its body that are used for detecting human touches. The organogel thus serves as a soft interface for recognizing the intentions of the human operators, enabling the robot to interact with them while generating desired motions of the manipulator. In addition to the touch sensors, each manipulator module has compact, soft string sensors for detecting the displacements of the bellow actuators. When combined with an inertial measurement unit (IMU), the manipulator module has a capability of estimating its own pose or orientation internally. We also propose a localization method that allows us to estimate the location of the manipulator module and to acquire the 3D information of the target point in an uncontrolled environment. The proposed method uses only a single depth camera combined with a deep learning model and is thus much simpler than those of conventional motion capture systems that usually require multiple cameras in a controlled environment. Using the feedback information from the internal sensors and camera, we implemented closed-loop control algorithms to carry out tasks of reaching and grasping objects. The manipulator module shows structural robustness and the performance reliability over 5,000 cycles of repeated actuation. It shows a steady-state error and a standard deviation of 0.8 mm and 0.3 mm, respectively, using the proposed localization method and the string sensor data. We demonstrate an application example of human–robot interaction that uses human touches as triggers to pick up and manipulate target objects. The proposed soft robotic arm can be easily installed in a variety of human workspaces, since it has the ability to interact safely with humans, eliminating the need for strict control of the environments for visual perception. We believe that the proposed system has the potential to integrate soft robots into our daily lives. [ABSTRACT FROM AUTHOR]

Ceramic stereolithography 3D printing technology has demonstrated great potential in alumina core manufacturing for advanced turbine blade casting. However, there have been very few photosensitive material formulas specifically designed for alumina core fabrications. Herein, we present the design of a 3D printable ceramic paste based on bimodal particle size distributions for additive manufacturing of high‐quality alumina cores. The coarse particles in the paste remain in their original shape while the fine particles transform into platelet‐like particles during sintering. The effects of coarse particles, platelet‐like particles, and grain growth on maintaining porosity and limiting shrinkage rates are studied. Furthermore, the vacuum sintering process is found to be beneficial for core material properties. The physical properties tests verify that the newly designed alumina paste in this work can meet the application requirement, which is superior to the previous research. [ABSTRACT FROM AUTHOR]

The aim of this study is to provide an overview of the current state-of-the-art in the fabrication of bioceramic scaffolds for bone tissue engineering, with an emphasis on the use of three-dimensional (3D) technologies coupled with generative design principles. The field of modern medicine has witnessed remarkable advancements and continuous innovation in recent decades, driven by a relentless desire to improve patient outcomes and quality of life. Central to this progress is the field of tissue engineering, which holds immense promise for regenerative medicine applications. Scaffolds are integral to tissue engineering and serve as 3D frameworks that support cell attachment, proliferation, and differentiation. A wide array of materials has been explored for the fabrication of scaffolds, including bioceramics (i.e., hydroxyapatite, beta-tricalcium phosphate, bioglasses) and bioceramic–polymer composites, each offering unique properties and functionalities tailored to specific applications. Several fabrication methods, such as thermal-induced phase separation, electrospinning, freeze-drying, gas foaming, particle leaching/solvent casting, fused deposition modeling, 3D printing, stereolithography and selective laser sintering, will be introduced and thoroughly analyzed and discussed from the point of view of their unique characteristics, which have proven invaluable for obtaining bioceramic scaffolds. Moreover, by highlighting the important role of generative design in scaffold optimization, this review seeks to pave the way for the development of innovative strategies and personalized solutions to address significant gaps in the current literature, mainly related to complex bone defects in bone tissue engineering. [ABSTRACT FROM AUTHOR]

High-performance ceramics are recognized as key enabling materials because of their very high thermal, chemical and mechanical resistance in combination with a lower density compared to most metals. These properties apparently predestine ceramics for many different applications, e.g. propulsion engines. Within the present work, the high potential of additive manufacturing in the field of ceramic materials (CerAMfacturing) could be demonstrated. It is possible to produce high-resolution ceramic aerospike engines using CerAM VPP. The manufactured components not only combine the typical ceramic properties, but also exhibit: - high geometric complexity, - very good surface properties, and - very good manufacturing accuracy. These developments will pave the way for a new generation of propulsion engines. • Ceramic aerospike engine additively manufactured by CerAM VPP. • No critical defects or deformations visible with NDT. • Very high resolution (slit width approx. 500 μm) and very good surface quality (R a < 2 μm). • Measurements on specific impulse showed very good reproducibility. [ABSTRACT FROM AUTHOR]

The complex structure of Ti/HA (HA: hydroxyapatite) implants prepared by additive manufacturing technology plays an essential role in its application in bone repair. Digital light processing (DLP) is widely used to prepare bioceramics with complex structures. However, it is a challenge to prepare Ti/HA biomaterials by DLP due to the high ultraviolet (UV) absorption of Ti powder. In the present work, TiH2 powder coated with a TiO2 layer is selected to reduce the UV absorption and improve the curing depth for DLP printed green bodies of TiO2@TiH2/HA, because the TiO2@TiH2 powder can be reduced by 12.7% compared to the TiH2 powder without any oxidation. Then, the shell layer of TiO2 undergoes dehydrogenation and reduction reaction with the core phase of TiH2 during the sintering process to transfer TiO2@TiH2/HA into TixOy@Ti/HA. In addition, the effects of HA content on compressive strength and biocompatibility are investigated in the TixOy@Ti/HA biomaterials. The results show that when adding 60 vol%HA, the maximum monolayer curing depth of the slurry reaches 90.1 ± 3.5 µm. 40%TixOy@Ti/60%HA shows the maximum effect in promoting the pre‐osteoblast differentiation and a relatively high compressive strength of 48.7 ± 3.5 MPa. This work provides an experimental basis for the preparation of ceramic–metal composites with high UV absorptivity using DLP. [ABSTRACT FROM AUTHOR]

Michael addition between thiol‐ and maleimide‐functionalized molecules is a long‐standing approach used for bioconjugation, hydrogel crosslinking, and the functionalization of other advanced materials. While the simplicity of this chemistry enables facile synthesis of hydrogels, network degradation is also desirable in many instances. Here, the susceptibility of thiol–maleimide bonds to radical‐mediated degradation is reported. Irreversible degradation in crosslinked materials is demonstrated using photoinitiated and chemically initiated radicals in hydrogels and linear polymers. The extent of degradation is shown to be dependent on initiator concentration. Using a model linear polymer system, the radical‐mediated mechanism of degradation is elucidated, in which the thiosuccinimide crosslink is converted to a succinimide and a new thioether formed with an initiator fragment. Using laser stereolithography, high‐fidelity spatiotemporal control over degradation in crosslinked gels is demonstrated. Ultimately, this work establishes a platform for controllable, radical‐mediated degradation in thiol–maleimide hydrogels, further expanding their versatility as functional materials. [ABSTRACT FROM AUTHOR]

Additive manufacturing is swiftly transitioning from a prototyping tool to a useful technology for industrial-scale manufacturing. As global industries seek to harness its potential, several 3D printing technologies have been successfully integrated into mainstream manufacturing workflows, based on the range of processable materials, fabrication mechanisms and integration into regulated environments. While metal 3D printing has established a significant niche in the context of aerospace and automotive manufacturing, the upscaled translation of polymer 3D printing lags, limited by several critical challenges, both in the materials domain, as well as the technical fabrication mechanisms. This article seeks to juxtapose the growth, challenges and opportunities of metal and polymer additive manufacturing, emphasizing the latter's potential for future growth in sectors such as polymer waste recycling and point-of-care medical device manufacturing. By dissecting the complexities surrounding feedstocks, manufacturing and post-processing workflows and the advances in simulations and quality control, this review provides comprehensive insights into the progression of 3D printed technologies for industrial-scale additive manufacturing into the future. [ABSTRACT FROM AUTHOR]

Developing affordable electrocatalysts is crucial for driving the sustainable energy transition to green hydrogen. Here, a generalizable method known as polymer infusion additive manufacturing is reported for transforming 3D‐printed photopolymers into core–shell micro lattice electrodes for electrocatalytic water splitting with transition metal/metal oxides/carbon heterointerfaces. The optimized free‐standing architectures integrate Cu/CuOx on carbon (Cu/CuOx/C) microlattices, yielding high electrocatalytic activity (overpotential of 145 mV at 10 mA cm−2 and a Tafel slope of 134 mV dec−1) and excellent durability for the hydrogen evolution reaction (HER) (>100 h), surpassing state‐of‐the‐art Cu foams. Additionally, for the oxygen evolution reaction (OER), Co/CoOx on carbon (Co/CoOx/C) microlattices display exceptional activity with the lowest overpotential (1.40 V to gain 10 mA cm−2) among all reported PGM‐free electrodes. The study explores the gas phase mass‐transport properties of these 3D microlattices via microscopic imaging of bubble evolution, finding that the outstanding electrocatalytic performance and long‐term stability of microlattice electrodes leverages their mesoscale (100–300 µm) pores, providing accessibility of electrolytes, maximizing utilization of active sites, and ensuring rapid evolution of gas bubbles. Thus, a simple but pioneering method is introduced for manufacturing 3D mesostructured electrocatalysts with deep control of liquid and gas phase mass‐transport, enhancing the efficacy of alkaline water electrolysis. [ABSTRACT FROM AUTHOR]

3D printing technology holds tremendous promise for applications in the medical field, particularly in the creation of anatomical models. The accuracy of 3D-printed anatomical models is of utmost importance, especially for surgeons engaged in complex surgical planning. The goal of this study was to create an anatomically precise model of brain tissue using data obtained from an MRI scan, with a resin-based Masked Stereolithography 3D printer, and to assess the model's potential uses. The process of creating an anatomical brain model with an SLA 3D printer was divided into six fundamental stages. The 3D printing process for this project necessitated 55.4 g of resin, and the total printing time was 4 h and 56 min. Any liquid resin residues on the brain structure eliminated through cleaning have been conducted using 99.6 % pure isopropyl alcohol. Following the printing phase, the produced model underwent a curing process in a chamber illuminated with ultraviolet light at a wavelength of 405 nm to ensure complete solidification. Once solidification is completed, the dimensions of the brain are measured with a micrometer and compared with those digitally generated from the MRI scan data. The results showed that the overall dimensional error was less than 1 %. [Display omitted] [ABSTRACT FROM AUTHOR]

The capacity of additive manufacturing and three-dimensional (3D) printing to quickly construct intricate structures and accurate geometries sets them apart from traditional production techniques. The fourth industrial revolution and the digitalization of production were fueled by the emergence of 3D printing, which was made possible by the increasing demand for goods with various designs, functions, and materials. The global influence of 3D printing on healthcare has resulted in the replacement of generic implanted medical devices with patient-customized implants. In the field of oral and maxillofacial surgery, where surgeons use precision medicine daily, this revolution has had a huge influence. Treatments enhanced by 3D technology include orthognathic surgery, complete joint replacement therapy, and trauma. Surgical teams now engage in the 3D design and production of devices at point-of-care treatment facilities with internal infrastructure thanks to the growing and broad adoption of 3D technology in clinical settings. The way doctors approach treatment planning and clinical results are affected greatly by 3D technology. While outlining significant clinical applications, the article presents our viewpoint on the use of 3D-based technology in the field of oral and maxillofacial surgery and the road ahead with the advent of Four-dimensional (4D) printing. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of the study was to investigate the effect of ethanol on the properties of acrylic-urethane resin products obtained by vat photopolymerization using the masked stereolithography method. The effect of alcohol at concentrations of 15, 25, and 35% in the resin on the chemical structure, weight, thickness of the samples, and mechanical properties in static tabltensile tests performed immediately after printing and one month later were studied. The results obtained were evaluated in terms of the use of ethanol as a cosolvent to help load the resin with agomelatine for the potential of obtaining microneedle transdermal systems. It was shown that in terms of stability of properties, the most favorable system was resin with the addition of alcohol at a concentration of 15%. The greatest changes induced by the presence of the solvent in the resin were observed in the case of tensile properties, where the alcohol caused a decrease in the plasticity of the material, reducing the relative elongation at break from 14% for the pure resin to 4% when the alcohol concentration was 35%. Young's modulus and tensile strength also decreased with the addition of alcohol by 18% and 31%, respectively, for testable samples with the maximum amount of alcohol in the resin. The deterioration in properties is most likely related to the effect of the solvent on the radical polymerization process of the resin, particularly the phenomenon of chain transfer to the solvent, which is important in view of the intended application of the developed material. [ABSTRACT FROM AUTHOR]

Copyright of Cirugía y Cirujanos is the property of Publicidad Permanyer SLU and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The conventional manufacturing chain for technical ceramics is too expensive for the production of small series or unique parts with complex designs. Hybrid machines that combine additive and subtractive processes can be an interesting solution to overcome this technology lock-in. However, despite the great interest in hybrid machines for metallic parts, there is a lack of data in the literature when it comes to ceramics. The purpose of this paper is to contribute to closing this gap. It is the first to evaluate the achievable geometrical tolerances according to ISO 2768-2 as well as the surface textures of composite zirconia parts shaped sequentially by pellet additive manufacturing (PAM, from ceramic injection molding feedstock) and finish milling. The green parts were then debinded and sintered to analyze the influence of these steps. Compared to the initial green parts, the sintered parts exhibited shiny and smooth surfaces with sharp edges. Flatness, parallelism and perpendicularity all achieved an H (fine) class, while the surface textures were significantly improved, resulting in arithmetic roughness (Ra) below 1.6 µm. [ABSTRACT FROM AUTHOR]

Objective: To assess and compare the accuracy of 3D-printed digital models, orthognathic surgical splints, retainers or aligners, and implant surgical guides printed using various 3D printing technologies. Methods: The search comprised prospective and retrospective studies related to the accuracy of 3D-printed models, splints, implant surgical guides, and retainers/aligners in patients undergoing orthodontic and orthognathic surgical procedures. The outcomes were assessed in terms of linear measurements, degree of fit, and positional deviations in comparison to conventional plaster models and surgical acrylic splints. The methodologic quality of the articles and the level of evidence were assessed using the QUADAS-2 tool. A meta-analysis was performed to compare the accuracy of models printed by different technologies to plaster models using the random-effects model. Results: Twenty-one retrospective studies were included. Quality assessment of all included articles showed moderate risk of bias and no article was excluded. The systematic review showed that there were no significant differences between printed surgical splints, retainers/aligners compared, and the control group. Meta-analysis of six eligible studies showed that printed models had a general trend toward overestimation of linear measurements (mean difference = 0.22mm; 95% confidence interval= - 0.09 to 0.36 mm, I 2 = 85%). Measurements made on digital light processing-printed models were significantly different than those made on plaster models. Conclusion: The mean difference of 0.22 mm in linear measurements made on 3D-printed models and plaster models was clinically acceptable. Among the various printing technologies, PolyJet and fused deposition modeling-printed models showed higher accuracy. The printed splints and retainers/aligners were as accurate and reliable as their respective gold standards. The findings should be interpreted with caution due to high level of heterogeneity. [ABSTRACT FROM AUTHOR]