Search Results (52)

Edible hydrogels are the central material class in 3D food printing because they reconcile two competing needs: (i) low resistance to flow under nozzle shear and (ii) fast recovery of elastic structure after deposition to preserve geometry. This review consolidates the recent years of progress on hydrogel formulations—gelatin, alginate, pectin, carrageenan, agar, starch-based gels, gellan, and cellulose derivatives, xanthan/konjac blends, protein–polysaccharide composites, and emulsion gels alongside a critical analysis of printing technologies relevant to food: extrusion, inkjet, binder jetting, and laser-based approaches. For each material, this review connects gelation triggers and compositional variables to rheology signatures that govern printability and then maps these to process windows and post-processing routes. This review consolidates a decision-oriented workflow for edible-hydrogel printability that links formulation variables, process parameters, and geometric fidelity through standardized test constructs (single line, bridge, thin wall) and rheology-anchored gates (e.g., yield stress and recovery). Building on these elements, a “printability map/window” is formalized to position inks within actionable operating regions, enabling recipe screening and process transfer. Compared with prior reviews, the emphasis is on decisions: what to measure, how to interpret it, and how to adjust inks and post-set enablers to meet target fidelity and texture. Reporting minima and a stability checklist are identified to close the loop from design to shelf. Full article

This study provides a comprehensive comparison of two leading direct-write manufacturing technologies: Aerosol Jet Printing (AJP) and Micro Dispensing Technology (MDT). The investigation examines their capabilities, limitations, and performance characteristics for printing on both 2D and 3D substrates. The findings offer valuable insights into the suitability of each printing method for flexible electronics based on the morphology and electrical performance of the deposited inks. The results reveal distinct advantages for each technique: AJP excels in resolution, while nScrypt’s micro dispensing offers superior 3D conformality, greater material versatility, and higher throughput. Full article

Electrohydrodynamic (EHD) printing offers mask-free, high-resolution deposition across a broad range of ink viscosities, yet combining void-free filling of high-aspect-ratio through-glass vias (TGVs) with ultrafine drop-on-demand (DOD) line printing on the same platform requires balancing conflicting requirements: for example, high field strengths to drive ink into deep and narrow vias; sufficiently high ink viscosity to prevent gravity-induced leakage; and stable meniscus dynamics to avoid satellite droplets and charge accumulation on the glass surface. By coupling electrostatic field analysis with transient level-set simulations, we establish a dimensionless regime map that delineates stable cone-jetting regime; these predictions are validated by high-speed imaging and surface profilometry. Operating within this window, the platform achieves complete, void-free filling of 200 µm × 1.52 mm TGVs and continuous 10 µm-wide traces in a single print pass. Demonstrating its capabilities, we fabricate transparent Ku-band substrate-integrated waveguide antennas on borosilicate glass: the printed vias and arc feed elements exhibit a reflection coefficient minimum of −18 dB at 14.2 GHz, a −10 dB bandwidth of 12.8–16.2 GHz, and an 8 dBi peak gain with 37° beam tilt, closely matching full-wave predictions. This physics-driven, all-in-one EHD approach provides a scalable route to high-performance, glass-integrated RF devices and transparent electronics. Full article

To address the challenge of imprecise micro-droplet formation control in piezoelectric jetting devices used in sand mold 3D printing and apply on-demand inkjet printing technology to sand mold manufacturing, this study first explains the working principle of a piezoelectric shear-mode printhead. A mathematical model of the droplet ejection process is then established based on Computational Fluid Dynamics (CFD). Building upon this model, numerical simulations of droplet generation, breakup, and flight are conducted by using the Volume of Fluid (VOF) model within the Fluent module of the Workbench 2020 R2 platform. Finally, under consistent driving conditions, the effects of key parameters—viscosity, surface tension, and inlet velocity—on the ejection process are investigated through simulation. Based on the results, appropriate ranges and recommended values for ink properties are determined. This study provides significant engineering value for improving the stability and precision of droplet formation in industrial sand mold 3D printing. Full article

Material Jetting (MJT) 3D printing (3DP) is a specific technology that deposits photocurable droplets of material and colored inks to fabricate objects layer-by-layer. The high resolution and full color capability render MJT 3DP an ideal technology for 3DP in medicine as evidenced by the 3DP literature. The technology has been adopted globally across the Americas, Europe, Asia, and Australia. While MJT 3D printers can be expensive, their ability to fabricate highly accurate and multi-color parts provides a lucrative opportunity in the creation of advanced prototypes and medical models. The literature on MJT 3DP has expanded greatly as of late, in part aided by the lowering costs of the technology, and this report is the first review to document the applications of MJT in medicine. Additionally, this report portrays the technological information behind MJT 3DP, cases involving fabricated MJT 3DP models from the University of Cincinnati 3DP lab, as well as the challenges of MJT in a clinical setting, including cost, expertise in managing the machines, and scalability issues. It is expected that MJT 3DP, as imaging and segmentation technologies undergo future improvement, will be best poised with representing the voxel-level-variations captured by radiologic-image-sets due to its capacity for voxel-level-control. Full article

In the context of sustainable fashion, this paper presents research on the impact of property assessment methods of textile materials and pigment digital printing on the mechanical properties of fabrics and their 3D simulation in the development of digital prototypes for clothing design. Six woven fabrics, with and without a textile ink-jet print, were tested using a KES-FB measuring system and digitized using SEDDI Textura AI technology. The determined mechanical parameters were used for 3D draping simulations based on Cusick Drape Meter method, as well as for the simulation of frilly women’s skirt models. The research showed a good correlation between the draping of real fabric samples and their 3D simulations, particularly supporting the use of AI for fabric assessments due to its sustainability. The drape analysis, performed on the digital 3D prototypes of a frilly women’s skirt model in two different lengths, showed the influence of fabric ink-jet printing on the drape properties, which can be explained by some structural parameters and determined changes in mechanical parameters between unprinted and printed fabric samples. The results provide valuable insights for objective evaluation of clothing digital 3D prototypes, which is a very significant element in the production process from a sustainability point of view and is becoming increasingly prominent as a method for developing new clothing designs that is gradually replacing the traditional, less environmentally friendly approach of creating numerous physical test samples. Full article

Green sustainable solvents have emerged as promising alternatives to petroleum-derived options, such as toluene. This study demonstrates the use of cyrene as an effective exfoliation medium for graphene nanoplatelets (GNPs) and hexagonal boron nitride (hBN) and molybdenum disulfide (MoS₂) particles. The incorporation of polyvinylpyrrolidone (PVP) attenuates the shear-thinning behavior of GNP and hBN suspensions, maintaining a constant shear viscosity over a wide range of shear rates regardless of PVP molecular weight. Despite the presence of polymer, elasticity is hindered by inertia effects, making it impossible to accurately measure the extensional relaxation time in the capillary breakup extensional rheometer (CaBER). Assuming the weak elasticity of the formulations has a negligible impact on the breakup mechanism, we estimated droplet sizes for drop-on-demand (DoD) inkjet printing and electrohydrodynamic (EHD) jet printing based on fluid properties, i.e., viscosity, surface tension and density, and nozzle inner diameter ($D_{nozzle}$). Results indicate that the droplet size ratio ($D_{drop}/D_{nozzle}$) in DoD printing can be up to two orders of magnitude higher than the one predicted for EHD jet printing at the same flow rate. This work highlights the potential of cyrene-based 2D inks as eco-friendly alternatives for advanced printing technologies. Full article

Conductive polymer materials, particularly PEDOT:PSS conductive polymers, have gained widespread attention due to their excellent conductivity, processability, and biocompatibility, making them highly applicable in fields such as bioelectrodes, flexible sensors, and soft robotics. With the rapid development of flexible electronics, the demand for micron-scale precision in the processing of conductive polymers grows. However, advanced fabrication techniques, such as 3D printing and screen printing, which are currently popular in research, face challenges in achieving a micron-level resolution, limiting the further application of conductive polymers. In this study, we demonstrate three types of PEDOT:PSS inks and systematically explore their suitability for electrohydrodynamic (EHD) jet printing. We investigate the impact of critical parameters, including voltage, printing speed, and printing height, on the accuracy of printed patterns. Among the formulations, the optimized PEDOT:PSS to ethylene glycol ratio of 1:1 achieves line widths of 20 µm. Based on this ink, we successfully print flexible conductive polymer patterns with line widths ranging from 20 µm to 90 µm and fabricate PEDOT:PSS conductive films with dimensions of 1.5 cm × 0.5 cm. This high-precision PEDOT:PSS ink demonstrates a strong potential for applications in high-density electrode arrays, electrochemical transistors, and brain–machine interfaces, paving the way for advanced flexible electronics. Full article

In recent years, 3D printing has emerged as a promising technology in energy storage, particularly for the fabrication of Li-ion battery electrodes. This innovative manufacturing method offers significant material composition and electrode structure flexibility, enabling more complex and efficient designs. While traditional Li-ion battery fabrication methods are well-established, 3D printing opens up new possibilities for enhancing battery performance by allowing for tailored geometries, efficient material usage, and integrating multifunctional components. This article examines three key 3D printing methods for fabricating Li-ion battery electrodes: (1) material extrusion (ME), which encompasses two subcategories—fused deposition modeling (FDM), also referred to as fused filament fabrication (FFF), and direct ink writing (DIW); (2) material jetting (MJ), including inkjet printing (IJP) and aerosol jet printing (AJP) methods; and (3) vat photopolymerization (VAT-P), which includes the stereolithographic apparatus (SLA) subcategory. These methods have been applied in fabricating substrates, thin-film electrodes, and electrolytes for half-cell and full-cell Li-ion batteries. This discussion focuses on their strengths, limitations, and potential advancements for energy storage applications. Full article

The aim of this study was to investigate whether PolyJet technology, which uses rubber-like materials for printing and is known for its high resolution and performance, could be suitable for producing flexographic printing plates. In our research, we designed test plates that were printed using PolyJet technology with TangoBlackPlus FLX9870-DM resin. These 3D-printed plates were evaluated for their resistance to various flexographic inks and solvents, and their contact angles were measured. Subsequently, the prints were made on a Flexiproof device using water-based ink with both the test plates and traditional photopolymer plates across six different substrates. The print quality was assessed using densitometry and spectrophotometry. Our findings indicate that the 3D-printed plates are suitable for printing solid areas and lines with water-based inks. However, the print quality of the 3D-printed plates is slightly lower than that of the photopolymer plates, with the optical density values for the high-quality prints on coated papers being approximately 10% lower. Additionally, the plates printed with TangoBlack Plus resin appear to be suitable for UV inks due to their high resistance, but they are not resistant to the solvents used in solvent-based inks. Full article

The technology to jet print metal lines with precise shape fidelity on diverse substrates is gaining higher interest across multiple research fields. It finds applications in additively manufactured flexible electronics, environmentally friendly and sustainable electronics, sensor devices for medical applications, and fabricating electrodes for solar cells. This paper provides an experimental investigation to deepen insights into the non-contact printing of solder lines using StarJet technology, eliminating the need for surface activation, substrate heating, curing, or post-processing. Moreover, it employs bulk metal instead of conventional inks or pastes, leading to cost-effective production and enhanced conductivity. The effect of molten metal temperature, substrate temperature, standoff distance, and printing velocity was investigated on polymer foils (i.e., PET sheets). Robust printing parameters were derived to print uniform, bulge-free, bulk metal lines suitable for additive manufacturing applications. The applicability of the derived parameters was extended to 3D-printed PLA, TPU, PA-GF, and PETG substrates having a much higher surface roughness. Additionally, a high aspect ratio of approx. 16:1 wall structure has been demonstrated by printing multiple metal lines on top of each other. While challenges persist, this study contributes to advancing additively manufactured electronic devices, highlighting the capabilities of StarJet metal jet-printing technology. Full article

The additive manufacturing (AM) of functional copper (Cu) parts is a major goal for many industries, from aerospace to automotive to electronics, because Cu has a high thermal and electrical conductivity as well as being ~10× cheaper than silver. Previous studies on AM of Cu have concentrated mainly on high-energy manufacturing processes such as Laser Powder Bed Fusion, Electron Beam Melting, and Binder Jetting. These processes all require high-temperature heat treatment in an oxygen-free environment. This paper shows an AM route to multi-layered microparts from novel nanoparticle (NP) Cu feedstocks, performed in an air environment, employing a low-power (<10 W) laser sintering process. Cu NP ink was deposited using two mechanisms, inkjet printing, and bar coating, followed by low-power laser exposure to induce particle consolidation. Initial parts were manufactured to a height of approximately 100 µm, which was achieved by multi-layer printing of 15 (bar-coated) to 300 (inkjetted) layers. There was no evidence of oxidised copper in the sintered material, but they were found to be low-density, porous structures. Nonetheless, electrical resistivity of ~28 × 10⁻⁸ Ω m was achieved. Overall, the aim of this study is to offer foundational knowledge for upscaling the process to additively manufacture Cu 3D parts of significant size via sequential nanometal ink deposition and low-power laser processing. Full article

We report the design, fabrication, and experimental characterization of an optically transparent printed planar inverted-F antenna (PIFA) operating at 2.45 GHz using the aerosol jet (AJ) printing method. The proposed antenna was fabricated using a clear conductive ink on glass and Delrin. The antenna exhibits a wide fractional bandwidth (FBW) of 20% centered at 2.45 GHz, with a peak realized gain of −3.6 dBi and transparency of ~80%. The proposed fabrication method provides a cost-effective and scalable solution for manufacturing transparent antennas with potential applications in wireless communication, sensing, and wearable devices operating at mmWave frequencies higher than 30 GHz. Full article

Optical fiber biosensors can be used to develop point-of-care tests (POCTs) for detecting viruses and bacteria in several matrices. In particular, the surface plasmon resonance (SPR) and localized SPR phenomena (LSPR) can be excited by exploiting low-cost and small-size optical fiber chips. Generally, SPR or LSPR sensors are realized using several kinds of modified optical fibers (silica, plastic, or specialty) or by exploiting other optical waveguides (e.g., slab, spoon-shaped waveguides, etc.). More specifically, optical fiber sensors can be classified as intrinsic or extrinsic. In the “optical fiber intrinsic sensors”, the sensing area is realized in the optical fiber directly, such as in the case of plasmonic platforms based on D-shaped plastic optical fibers (POFs), tapered optical fibers, U-bend POFs, or light-diffusing fibers (LDFs). By contrast, when an optical fiber is used as a mere waveguide allowing for the launch of light to the sensing region and its collection, it is defined as an extrinsic optical fiber sensor, like in the case of the plasmonic sensors realized by Cennamo et al. using POFs combined with spoon-shaped waveguides, 3D-printed platforms, bacterial cellulose waveguides, nanogratings, and InkJet-printed chips. To realize optical biosensor chips for the detection of viruses and bacteria, both intrinsic and extrinsic plasmonic POF sensors can be efficiently combined with receptors specific for membrane proteins, either biological (e.g., antibodies, aptamers, enzymes, etc.) or synthetic (e.g., molecularly imprinted polymers), to build groundbreaking POCTs. Full article

Additive manufacturing is a very rapidly developing industrial field. It opens many possibilities for the fast fabrication of complex-shaped products and devices, including functional materials and smart structures. This paper presents an overview of polymer 3D printing technologies currently used to produce magnetic materials and devices based on them. Technologies such as filament-fused modeling (FDM), direct ink writing (DIW), stereolithography (SLA), and binder jetting (BJ) are discussed. Their technological features, such as the optimal concentration of the filler, the shape and size of the filler particles, printing modes, etc., are considered to obtain bulk products with a high degree of detail and with a high level of magnetic properties. The polymer 3D technologies are compared with conventional technologies for manufacturing polymer-bonded magnets and with metal 3D technologies. This paper shows prospective areas of application of 3D polymer technologies for fabricating the magnetic elements of complex shapes, such as shim elements with an optimized shape and topology; advanced transformer cores; sensors; and, in particular, the fabrication of soft robots with a fast response to magnetic stimuli and composites based on smart fillers. Full article