Printing Devices Research Articles

Effect of yttrium nitrate coating on the vat photopolymerization forming process and sintering properties of aluminum nitride ceramics

In this study, a ball-milling method was successfully used to coat yttrium nitrate on the surface of aluminum nitride (AlN) powder and the effects of yttrium nitrate content on the AlN powder particle size, viscosity and curing behavior of the AlN suspension, and performance and microstructure of the sintered AlN bodies were investigated. The results indicated that the AlN powder surface coating significantly reduced the viscosity of the suspension and enhanced the cure depth while increasing the powder particle size, which in turn reduced the stability of the suspension. By studying the performance of sintered bodies, it was found that as the yttrium nitrate content increased, the AlN thermal conductivity and flexural strength initially increased and then decreased. Microstructural analysis results revealed that the second phase in samples with 9.23 and 14.49 wt% yttrium nitrate exhibited an island-like distribution, whereas in samples with 19.18 wt% yttrium nitrate, the second phase exhibited a continuous distribution. Finally, the heat-dissipation performance of AlN components with different structures was also studied, and testing was conducted on the driving chip of a 3D printing device. The results indicated that complex-structured AlN ceramic components exhibited an excellent heat-dissipation performance.

3D Printing of Gradient-Doped Yb:YAG Laser Ceramics by Leveraging Active Mixing

Gradient-doped laser ceramics fabricated via 3D printing have great potential for high-power laser applications. However, it is challenging to produce such types of gain media because it is inconvenient to fabricate different component slurries prepared offline using traditional methods precisely. To address these issues, a facile approach for the additive manufacturing of high-power laser ceramics is proposed for gradient structure fabrication. First, a material-extrusion-based 3D printing device with a homemade active mixing module is developed to fabricate gradient-doped Yb:YAG(Y3Al5O12) laser ceramics using two slurries with different doping concentrations. Subsequently, the active mixing module is systematically investigated to obtain different Yb-doped concentrations of printing slurries with a uniform element distribution. By measuring the switching delay volume between different components, a proper volume adjustment enables the Yb concentration distribution of the green bodies to be consistent with the designed profile in the 3D process. Finally, multi-component (0–5–10–5–0 at% Yb:YAG) green bodies are printed, and experimental tests are conducted to evaluate the performance of these gradient-doped laser ceramics. The results show that the gradient-doped ceramic obtained 82.1% in-line transmittance at 1100 nm (4.6 mm thickness, along with the doping concentration gradient) and the average Yb ions diffusion distance across the interface fitted in the 20–30 μm range. Furthermore, a 1030 nm laser output with an output power of 4.5 W with a slope efficiency of 41.3% is achieved when pumped with a 940 nm laser diode. This study provides useful insights for developing various gradient rare-earth-doped laser ceramics for high-power laser applications.

A new adsorptive 3D–printed sampling device for simultaneous determination of 63 urinary organic acids by LC–MS/MS

BackgroundThe detection and quantification of urinary metabolites play an important role in disease diagnosis. In most cases, urinary analyses are done with liquid urine samples, which must be quickly transported to the laboratory to avoid metabolites degradation that is associated with temperature fluctuations. Consequently, dried sampling devices have emerged to minimize analyte degradation. However, most commercial dried sampling devices are expensive, aggregate low volumes, and need better analytical sensitivity. Therefore, a new dry urine sampling device that is inexpensive, suitable for domestic sampling operation, and efficient for quantifying metabolites without requiring high–resolution instruments is proposed in the present study. ResultsThe newly designed dry urine sampling device was produced by 3D printing that efficiently determines 63 urinary organic acids using liquid chromatography coupled with mass spectrometry (LC–MS/MS). The system's efficiency was demonstrated with analytical figures of merit, such as precision, accuracy, and stability of analytes after the sampling and storing of ordinary urine samples. The limits of quantification ranged from 0.01 to 0.42 ng mL–1. Precision and accuracy tests showed relative standard deviations of less than 15 %. The urine stability in the sampling device was high within seven days without any significant degradation of the metabolites. The method was applied to the analysis of 10 human urine samples and compared to a conventional method without the use of the sampling device. The results showed no statistically significant differences, demonstrating the method's efficiency. SignificanceThe proposed 3–D printing device was developed with fast, low–cost manufacturing features and can be manufactured with different volumetric capacities, adaptable to the needs of each user. Furthermore, it is innovative because this is the first sampling device that is effective for the simultaneous storage and preservation of several important urinary metabolites. Thus, it is anticipated that its application would contribute significantly to the identification of metabolic disorders.

A Water-Processed Mesoscale Structure Enables 18.5% Efficient Binary Layer-by-Layer Organic Solar Cells.

The two-step layer-by-layer (LBL) deposition of donor and acceptor films enables desired vertical phase separation and high performance in organic solar cells (OSCs), which becomes a promising technology for large-scale printing devices. However, limitations including the use of toxic solvents and unpredictable infiltration between donor and acceptor still hinder the commercial production of LBL OSCs. Herein, we developed a water-based nanoparticle (NP) ink containing donor polymer to construct a mesoscale structure that could be infiltrated with an acceptor solution. Using non-halogen o-xylene for acceptor deposition, the LBL strategy with a mesoscale structure delivered outstanding efficiencies of 18.5% for binary PM6:L8-BObased LBL OSCs. Enhanced charge carrier mobility and restricted trap states were observed in the meso-LBL devices with optimized vertical morphology. It is believed that the findings in this work will bring about more research interest and effort on eco-friendly processing in preparation for the industrial production of OSCs.

Optimization of Laser-Induced Graphene Electrodes for High Voltage Micro-Supercapacitors

With the development of grid-based distributed sensing with low-power electronics, the need for delocalized power supplies, Energy Storage Devices (ESDs) are moving toward miniaturized scales. Among ESDs, micro-supercapacitors (µSC) are currently under development as an alternative or complementary power supply/backup to batteries. Laser-induced graphene (LIG) is an emerging technology based on the laser conversion of polymers into graphene-based conductive materials. Polyimide (PI) is the most investigated polymer, moreover, it finds several applications in the electronics field. Laser scribing of polymers fastens the device processing reducing the number of wet chemistry steps carried out to fabricate micro-devices.PI Kapton foils of 125 µm thickness were used as substrate materials to produce LIG samples. A CO2 laser was exploited to convert polymeric samples and to pattern hard masks to print devices of optimized geometry and material properties. Further, electrodeposition processes can be used to increase the material capacity by depositing transition metal oxides with pseudocapacitive features. Among them, maganese oxide can be electrodeposited anodically without recurring to any thermal step. Tuning the LIG storage mechanism, and combining them, allows several degrees of freedom to design devices able to work in organic electrolyte environments in voltage windows ranging from 2.5 V up to 4.5 V. Moreover, optimization of electrode charges allows for improving the overall device lifetime and energetic efficiency.

Dimerized small molecular acceptors: Regulation of dimer conformation realizes binary organic solar cells with highly comprehensive performance

Dimerized small-molecular-acceptors (DSMA)-based organic solar cells have gained much progress but insufficient flexibility of the rigid DSMAs limits application in wearable electronics. By regulating dimer conformation, a series of DSMAs (2BOHD-T, 2BOHD-TCxT (x = 4, 6)) are synthesized through microwave-assist-reaction. Conformation evolution from 2-dimension planarity to 3-dimension architecture evoked by linkage engineering from rigidity to flexibility precisely controls the electronic structures, intermolecular interactions, film-forming processes, and flexibility of DSMAs. The rigid terminal-linked 2BOHD-T performs best in small-area devices with efficiency of 17.68%. The 3-dimensional flexible terminal-linked 2BOHD-TC4T achieves a record efficiency of 16.50% with a notable VOC of 0.980 V among the reported flexible DSMAs. 2BOHD-TC4T-based large-area printing device obtains the best efficiency (14.53%) among these acceptors. Furthermore, PM6:2BOHD-TC4T not only improves thermal stability close to the all-polymer system but also achieves an excellent crack onset strain, producing the large-area flexible device with excellent bending tolerance. An updated evaluation parameter, efficiency-stretchability-thermal stability-factor (ESSTF), is proposed. 2BOHD-TC4T-based device yields the highest ESSTF, demonstrating the most balanced large-area device efficiency, thermal stability, and mechanical robustness.

Solvent-free high-performance photocurable 3D printing resin from a noncoplanar branched maleimide oligomer for high-resolution fabrication

The ever-increasing requirements of photosensitive materials are put forward by the increase in the applications of photocuring 3D printing in high-tech fields. Nevertheless, the poor compatibility between high-performance resins and photocurable monomers renders challenges associated with the preparation of solvent-free resins with excellent comprehensive properties. In this work, a maleimide oligomer with a noncoplanar branched structure is synthesized in one step, which can be dissolved in a photocurable monomer. A low-viscosity, high-performance photocurable resin is prepared without an organic solvent and printed in layer by layer into a high-resolution (50 µm) three-dimensional complex shape. The material’s crosslinking density is further increased by thermal curing, achieving a improvement in mechanical properties. The printing device exhibits an storage modulus of up to 1.9 GPa at 200 °C and a dimensional shrinkage of less than 4%; it can also support a heavy object that exceeds its own weight by 1124 times. This resin achieves the balance between the viscosity, printing accuracy, and performance, demonstrating immense application potential in microelectronics, aerospace, etc.

On the dynamics of head-on collision of sessile droplets on the traveling substrate

In this work, the dynamics of the head-on collision of two sessile water droplets, namely the moving droplet and pinning droplet, on a traveling substrate was experimentally investigated. Unlike the traditional scenario of sessile droplets collision, the traveling substrate propelled the moving droplet attached to it to move at a certain speed. The results revealed that there are only two distinct regimes of collision consequences: coalescence without separation and separation with separation. A series of time-resolved photographic images mapping all the collision regimes in the parameter space of Capillary number and size ratio were used to identify the controlling factors for different collision results. The breakup of the receding meniscus in separation regime was discussed in detail as it is caused by the change of the droplet morphology. The findings indicated that the length of the receding meniscus played a significant role in the droplet impact dynamics, and when it exceeded about 8.2 mm, the receding meniscus broke up. Furthermore, it was demonstrated that the sum of the volume of initial pinning droplet’s receding meniscus and the volume of the moving droplet before collision is equal to the volume of the receding meniscus at its maximum length after collision. The critical Capillary number/size ratio for the transition between these two regimes was derived based on the volume principle before and after the collision. The model-predicated results show good agreement with the experiments. The findings could contribute to a better understanding of the droplet collision dynamics and the optimization of the anti-icing, self-cleaning and inkjet printing devices.

Multipotent Mesenchymal Cells Homing and Differentiation on Poly(ε-caprolactone) Blended with 20% Tricalcium Phosphate and Polylactic Acid Incorporating 10% Hydroxyapatite 3D-Printed Scaffolds via a Commercial Fused Deposition Modeling 3D Device.

As highlighted by the 'Global Burden of Disease Study 2019' conducted by the World Health Organization, ensuring fair access to medical care through affordable and targeted treatments remains crucial for an ethical global healthcare system. Given the escalating demand for advanced and urgently needed solutions in regenerative bone procedures, the critical role of biopolymers emerges as a paramount necessity, offering a groundbreaking avenue to address pressing medical needs and revolutionize the landscape of bone regeneration therapies. Polymers emerge as excellent solutions due to their versatility, making them reliable materials for 3D printing. The development and widespread adoption of this technology would impact production costs and enhance access to related healthcare services. For instance, in dentistry, the use of commercial polymers blended with β-tricalcium phosphate (TCP) is driven by the need to print a standardized product with osteoconductive features. However, modernization is required to bridge the gap between biomaterial innovation and the ability to print them through commercial printing devices. Here we showed, for the first time, the metabolic behavior and the lineage commitment of bone marrow-derived multipotent mesenchymal cells (MSCs) on the 3D-printed substrates poly(e-caprolactone) combined with 20% tricalcium phosphate (PCL + 20% β-TCP) and L-polylactic acid (PLLA) combined with 10% hydroxyapatite (PLLA + 10% HA). Although there are limitations in printing additive-enriched polymers with a predictable and short half-life, the tested 3D-printed biomaterials were highly efficient in supporting osteoinductivity. Indeed, considering different temporal sequences, both 3D-printed biomaterials resulted as optimal scaffolds for MSCs' commitment toward mature bone cells. Of interest, PLLA + 10% HA substrates hold the confirmation as the finest material for osteoinduction of MSCs.

Study of tension control systems for automatic rotogravure machines

In the manufacturing sector, a large number of machines today use automation technologies. Production will grow and speed up thanks to automation technologies, which includes using rotogravure machines. A machine using a printing technique known as a rotogravure machine is frequently used to print packaging on materials like paper or plastic. No one presently makes fully automatic rotogravure machines in Indonesia. Tension control is one of the automation systems of a rotogravure machine. In this research, tension control, kinds of tension control, and the building of a rotogravure machine tension control system are all topics that will be covered. It uses a descriptive qualitative approach. employing a literature review to gather data and descriptive statistics to analyze it. The study's findings demonstrate that the rotogravure machine is a fast printing device that uses substrates like paper, aluminum, and plastic. The printing procedure begins with the unwinding roll, moves to the infeed, and then continues with the first and second color printing processes, moving as necessary to the outfeed and rewinding roll using a tension control mechanism. The roller-to-roll mechanism used by the machine allows for the tension management because the printed material is subjected to varying strains that must be managed. A rotogravure machine can use four different forms of tension management, specifically speed control for unwinding and rewinding, speed control for unwinding and torque control for rewinding, and speed control for unwinding and rewinding. the creation of a tension control system for a rotogravure machine using the machine's main controller, a PLC and an HMI.

Influence of DLP and SLA printer technology on the accuracy of surgical guides for implant dentistry in free-end situations.

The present in vitro study aimed to compare the accuracy of the implant position inserted by surgical guides manufactured by three different 3D printers (one SLA and two DLP) and a subtractive manufacturing technique for a free-end situation. Surgical guides were manufactured using three different 3D printers, one SLA printer (Form 2; Formlabs) and two DLP printers (D20 II; Rapid Shape, and SolFlex 350; W2P Engineering). Surgical guides manufactured using the conventional CAD/CAM-based subtractive method served as controls. In total, 48 surgical guides were printed and assessed for accuracy. The guides were used for the placement of implants at tooth position 37. The postoperative implant position was digitally scanned for metric comparison with the preoperatively planned implant position. Significant differences were found when the SLA and DLP printers were compared. The SLA printer showed significantly lower accuracy in implant displacement at crest (P = 0.032) and angular displacement (P = 0.049) compared with the two DLP printers. The DLP printers showed comparable values to the control group. The results were within an acceptable clinical range. DLP technology seems to be superior to conventional SLA technology in terms of the accuracy of 3D-printed surgical guides when used for placement of implants in free-end situations.

Printing flexible thin-film transistors

Flexible thin-film transistors (f-TFTs) not only attract research attention but also possess significant application potential in various fields, such as consumer electronics, human–machine interfaces, healthcare, multipurpose sensors, and logic circuits. Printing is one of the most appealing technologies for fabricating f-TFTs owing to its low cost, suitability for large-scale fabrication, and possibility to be customized under non-vacuum conditions. Significant advancements have been achieved in the printing of f-TFTs regarding several aspects, including printing techniques, printable materials, device performance, and applications, which are summarized and discussed here. Specifically, this review focuses on the recent developments achieved regarding four typical materials commonly used in printed f-TFTs: low-dimensional materials, carbon-based materials, organic materials, and metal-oxide materials. Furthermore, the actual applications of printed f-TFTs are discussed to highlight the issues in contemporary research, and future outlook and prospects regarding the development of printed f-TFTs are provided.

DETERMINATION OF THE FACT OF TECHNICAL FORGERY OF A SIGNATURE IN THE ERA OF DIGITAL TECHNOLOGIES: PROBLEMS AND PERSPECTIVES

The task of establishing the authenticity of document details, primarily signatures and handwritten notes by their executor, becomes relevant in connection with the development of copying and reproduction equipment and printing devices associated with software and computer tools that allow editing original images or copying and change the content of records made on behalf of other persons and pass them off as genuine. Traditional methods of forging a technical signature are becoming increasingly obsolete, and there is a growing need for the development of new methods and technologies for protection against forgery. One such technology is the reproduction of signatures using reproductions, which are produced using a plotter that uses a ballpoint pen as a printing device. This technology makes it possible to reproduce signatures with high accuracy and quality and to convey small signs of any handwritten object, which, in turn, makes it extremely difficult for an expert to establish the fact and method of its technical imitation. In connection with the use of modern techniques for reproducing handwritten objects, publications on this topic began to appear in the scientific literature, but these works are clearly not enough. This fact arouses interest in a deeper study of the problems of using new technologies for the forgery of documents, including from experts who conduct forensic examinations in this field and need scientific development of methods of performing handwriting objects using new technical means. The result of the presented review was practical recommendations that allow us to discover a new technique of reproduction of signatures, namely, the technology of reproduction of a signature with the help of reproduction, which is carried out with the help of a plotter. The developed recommendations can be used by forensic experts in the field of technical forensic examination of documents and will prevent possible expert errors.

Hardness and modulus programmable tuning for silicone 3D printing device and experiment

PurposeThe purpose of this study was to fabricate silicone products that had different hardnesses and moduli, thus partially addressing the limitations of homogeneous materials whose deformation depends on altered structure or dimensions, and to provide new dimensions for the design of silicone soft structures.Design/methodology/approachA soft material three-dimensional printing platform with a dual-channel printing capability was designed and built. Using the material extrusion method, material screening was first performed using single-channel printing, followed by dual-channel-regulated printing experiments on products having different hardness and modulus values.FindingsThe proportion of additives has an effect on the accuracy of the printed product. Material screening revealed that Sylgard 527 and SE 1700 could be printed without additives. The hardness and mechanical properties of products are related to the percentage in their composition of hard and soft materials. The hardness of the products could be adjusted from 26A to 42A and the Young’s modulus from 0.875 to 2.378 Mpa.Originality/valueExisting silicone products molded by casting or printing are mostly composed of a single material, whose uniform hardness and modulus cannot meet the demand for differentiated deformation in the structure. The existing multihardness silicone material printing method has the problems of long material mixing time and slow hardness switching and complicated multi-extrusion head switching. In this study, a simple, low-cost and responsive material extrusion-based hardness programmable preparation method for silicone materials is proposed.

Chelate complexed multi-elemental printing performance of a small and cost efficient picoliter droplet printing device for micro preparation

We introduce an inexpensive modular picoliter pipetting device using modified commercially available thermal inkjet cartridges. The system is capable of reliable deposition of 65 elements. The printing solutions were modified to prevent the dissolution of Ni from the nozzle head, keeping those at a pH of >9. Loss of cations to the glass surfaces inside the nozzle head is prevented by forming anionic complexes with ethylenediaminetetraacetic acid in basic conditions. For some elements, e.g., Si, additives like tetramethylammonium hydroxide are necessary.The volumes of the droplets were obtained, weighing 30,000–360,000 droplets ejected by the printer using a laboratory scale. The droplet volume was within a range of 142–184 pL, depending on the formulation. The delivered elemental masses and the reproducibility were determined using total reflection X-ray fluorescence analysis and inductively coupled plasma optical emission spectrometry. Delivered masses were in the range of 0.98 pg – 11.9 pg per element and droplet.The shape of deposits of about 31 pg per element was studied using atomic force microscopy, optical microscopy, and confocal laser scanning microscopy. They were mostly spherical and ca. 14 μm in diameter and ca. 2 μm in height. The broad range of printable elements allows for the micro preparation of solid compounds for establishing a grazing incidence X-ray diffraction analysis library. As an example, the MgAl2O4 spinel was synthesized by printing of the formulation and subsequent calcination. Here we show its performance for the preparation of minerals in the context of recycling of critical elements from pyrometallurgical slags.

Study of Forming Performance and Characterization of DLP 3D Printed Parts.

In order to explore the effect of printing parameter configurations on the forming performance of Digital Light Processing (DLP) 3D printed samples, printing experiments were carried out on the enhanced adhesion and efficient demolding of DLP 3D printing devices. The molding accuracy and mechanical properties of the printed samples with different thickness configurations were tested. The test results show that when the layer thickness increases from 0.02 mm to 0.22 mm, the dimensional accuracy in the X and Y directions increases first and then decreases, while the dimensional accuracy in the Z direction decreases, and the dimensional accuracy is the highest when the layer thickness is 0.1 mm. The mechanical properties of the samples decline with an increasing layer thickness of the samples. The mechanical properties of the 0.08 mm layer thickness are the best, and the tensile, bending, and impact properties are 22.86 Mpa, 48.4 Mpa, and 35.467 KJ/m2, respectively. Under the condition of ensuring molding accuracy, the optimal layer thickness of the printing device is determined to be 0.1 mm. The analysis of the section morphology of samples with different thicknesses illustrates that the fracture of the sample is a river-like brittle fracture, and there are no defects such as pores in the section of samples.

Four-Dimensional Printing of Temperature-Responsive Liquid Crystal Elastomers with Programmable Shape-Changing Behavior.

Liquid crystal elastomers (LCEs) are polymer networks that exhibit anisotropic liquid crystalline properties while maintaining the properties of elastomers, presenting reversible high-speed and large-scale actuation in response to external stimuli. Herein, we formulated a non-toxic, low-temperature liquid crystal (LC) ink for temperature-controlled direct ink writing 3D printing. The rheological properties of the LC ink were verified under different temperatures given the phase transition temperature of 63 °C measured by the DSC test. Afterwards, the effects of printing speed, printing temperature, and actuation temperature on the actuation strain of printed LCEs structures were investigated within adjustable ranges. In addition, it was demonstrated that the printing direction can modulate the LCEs to exhibit different actuation behaviors. Finally, by sequentially conforming structures and programming the printing parameters, it showed the deformation behavior of a variety of complex structures. By integrating with 4D printing and digital device architectures, this unique reversible deformation property will help LCEs presented here apply to mechanical actuators, smart surfaces, micro-robots, etc.

Three-Dimensional Printing of a Tough Polymer Composite Gel Ink Reinforced with Chemically Modified Cellulose Nanofibrils Showing Self-Healing Behavior

Three-dimensional (3D) gel printing has significant potential for producing structurally accurate biomaterials based on complex biological tissues for use in regenerative biotechnology. The efficiency depends on the chosen gel printing device and the parameters used but also primarily on the selection of the gel ink. In the present study, the dimerizing functions in ureidopyrimidinone (UPy) were exploited to develop a gel ink. A composite gel ink was developed made out of a polymer consisting of UPy and di(ethylene glycol) ethyl ether (DEGEEA) functions and modified cellulose nanofibril-containing UPy groups (CNF-g-UPy) as print performance-enhancing additives. This resulted in a hyper-cross-linked network with superior mechanical strength compared to the matrix itself, with an increase of 3.7× in storage modulus and 2.8× in loss modulus. The CNF-g-UPy/UPy-DEGEEA gel ink exhibited shear-thinning properties and could therefore be extruded to form uniform strands with no merging and retain a relatively stable structure. The self-healing ability was demonstrated by the adhesion of two printed patterns after 2 min at 80 °C. The multiple cross-linkages and self-healing ability of the filaments, therefore, allow for stable printed structures. All of these findings point out the promising potential of such gel ink for many biotechnological applications.

Developing a Quality Evaluation System for Color Reproduction of Color 3D Printing Based on MATLAB Multi-Metrics.

Color 3D printing has been widely used in many fields such as cultural, medical, industrial, and food. The color reproduction accuracy of 3D printed products in these fields is becoming increasingly demanding, which requires more reproduction methods and practical tools. At present, most color 3D printing devices use one quantitative index, that is, color difference, to directly predict the color reproduction quality. However, this single quantitative index is not optimal for the curved surface of 3D printed color objects. Based on color evaluation principles, in this study, five new quantitative metrics consisting of color gamut comparison index, color SSIM index, color FSIM index, iCID index, and subjective scaling values are proposed for comparison, and the corresponding GUI design and code implementation of new color quality evaluation system are performed by MATLAB. Moreover, the comprehensive color assessment of color 3D printed products is confirmed by utilizing standard image acquisition and microscopic imaging methods that are not limited to printing materials and sampling locations. The operation of this system is validated to provide interactivity, simplicity and high efficiency. As a result, the system can provide new valuable feedback for color separation and output calibration of color 3D printing devices.

Printable Epsilon-Type Structure Transistor Arrays with Highly Reliable Physical Unclonable Functions.

Printed electronics promises to drive the future data-intensive technologies, with its potential to fabricate novel devices over a large area with low cost on nontraditional substrates. In these emerging technologies, there exists a large digital information flow, which requires secure communication and authentication. Physical unclonable functions (PUFs) offer a promising built-in hardware-security system comparable to biometrical data, which can be constructed by device-specific intrinsic variations in the additive manufacturing process of active devices. However, printed PUFs typically exploit the inherent variation in layer thickness and roughness of active devices. The current in devices with enough significant changes to increase the robustness to external environment noise is still a challenge. Here, printable epsilon-type-structure indium tin oxide transistor arrays are demonstrated to construct high-reliability PUFs by modifying the coffee-ring structure. The epsilon-type structure improves the printing scalability, film quality, and device reliability. Furthermore, the print-induced uncertainty along the channel thickness and length can lead to changes in the carrier concentration. Notably, the randomly distributed printing droplets in a small area significantly increase this uncertainty. As a result, the PUFs exhibit near-ideal uniformity, uniqueness, randomness, and reliability. Additionally, the PUFs are resilient against machine-learning-based attacks with a prediction accuracy of only 55% without postprocessing.