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Polymer composites with continuous fibers are expected to exhibit good mechanical performance due to orientation and high aspect ratio of fillers. Fused filament fabrication (FFF) provides an affordable method for processing these materials as products with tunable architecture. By incorporating continuous bioactive fibers coated with biodegradable polymer, the degradation rate of printed scaffolds may vary over time. As proof of concept, macroporous composites were 3D printed using continuous glass fiber‐reinforced polycaprolactone filament. Parametrization and challenges associated with printing on non‐dedicated equipment are discussed. A model describing the melt flow was employed to evaluate the velocity and shear rate profiles. Although the maximum velocity is approximately 18 mm s−1 for both neat and reinforced polymer, the obstruction caused by fibers results in higher shear rate, up to 481 s−1, higher pressure gradient, 1.95 MPa mm−1, and higher velocity gradient, conditions that limit print quality. Additionally, it was also possible to determine the shear stress experienced by the fiber bundle, 300 KPa, and the influence of different processing conditions. This investigation advances the development and understanding of manufacturing of continuous fiber‐reinforced polymers via FFF. [ABSTRACT FROM AUTHOR]

Copyright of Packaging & Food Machinery is the property of Packaging & Food Machinery Magazine 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 tension system is one of the most critical systems in gravure printed electronic equipment. It possesses a complex structure that spans the entire feeding process, from unwinding through printing to rewinding. This article focuses on the research of multi-span tension control for printing systems. Firstly, the characteristics and requirements of the tension-control system in the printing section were analyzed, and a multi-span tension-control structure was devised. Then, based on the coupled mathematical model of the multi-span tension system, a static decoupling model was formulated, and a first-order active disturbance rejection control (ADRC) controller was designed utilizing active disturbance rejection control technology. Finally, to verify the control performance of the ADRC decoupling controller for the printing tension system, simulation and experimental studies were conducted using MATLAB/Simulink R2018a and a dedicated experimental platform, and the results were then compared with those obtained from a traditional PID controller. The research findings indicate that the designed multi-span tension-control system demonstrates outstanding decoupling performance and anti-interference capabilities, effectively enhancing the tension-control accuracy of gravure printed electronic equipment. [ABSTRACT FROM AUTHOR]

Extrusion-based 3D bioprinting techniques are revolutionizing bioengineering by facilitating the creation of complex 3D microstructures. This review offers a thorough overview of extrusion-based 3D bioprinting methods, particularly highlighting the innovative electric-assisted coil-write 3D bioprinting technology. The review begins by explicating the fundamental principles underlying various extrusion-based 3D bioprinting technologies. It covers the printing equipment composition, suitable materials for 3D bioprinting, and the latest breakthroughs in technology. A critical aspect of this review is the in-depth comparison of the strengths and weaknesses associated with each 3D bioprinting approach. The electro-microfluidic extrusion method and the electric-assisted coil-write 3D bioprinting technology are highlighted. This advanced technology successfully overcomes the limitations of conventional extrusion-based methods, notably in the precise printing of intricately curved line structures with high resolution and speed. This method ingeniously integrates mechanical motion for creating microscale features with electrical coiling for sub-micron details, thus achieving remarkable printing speeds and structural complexity. This review concludes by exploring the potential applications and future advancements of this state-of-the-art technology. It underscores the ability of electric-assisted coil-write 3D bioprinting to develop pioneering materials and micro-devices for a variety of technological sectors, highlighting its transformative impact in bioengineering. [ABSTRACT FROM AUTHOR]

In this study, a computational fluid dynamics and discrete element (CFD–DEM) coupling model for sorting fresh tea leaves by aspirated‐air type was established, an experimental study of adsorption on bench was carried out, and computational fluid dynamics (fluent) was used to analyze the flow characteristics of two kinds of air‐suction tea leaf models, The coupling model of CFD–DEM is established, the motion process of fresh tea leaves from being adsorbed by a porous turntable to moving and falling with the turntable was simulated, 3D printing technology was used to print the key parts of the air suction tea leaf sorting equipment, and the porous turntable adsorption test of air suction tea leaf sorting was carried out. The results show that the model with the falling guard device has no airflow at the hole of the porous turntable, and the gas field flow characteristics are stable, which can ensure the smooth falling of fresh tea leaves; The results of the bench test for the separation of fresh tea leaves by air suction are the same as those simulated by the established CFD–DEM coupling model, which indicates that the establishment of the CFD–DEM coupling model and the simulation parameters are reasonable, and the coupling model lays a foundation for the later optimization and design of the multi‐scale air suction separation mechanism for tea particles. Practical applications: This research is applied to the field of food engineering and sorting of fresh tea leaves. This research innovatively proposes the principle of air‐suction sorting of fresh tea leaves. The air sucked in by negative pressure can carry out the next operation and save energy better. In this study, a CFD–DEM coupling model for air‐suction separation of fresh tea leaves was established. The key components of air‐suction separation equipment were printed using 3D printing technology, and the test results were the same as the simulation results. [ABSTRACT FROM AUTHOR]

To improve the performance of the tension control system in gravure printed electronic equipment, it is necessary to study the tension system model of gravure-printing electronic equipment. This paper focuses on the coupling characteristics of multi-span tension systems. Firstly, based on the single-span tension model, the mathematical model of the printing tension subsystem is established and simplified into a general multi-span tension coupling model. Then, using the relationship between the inputs and outputs of the system, the coupling model is simulated using MATLAB/Simulink and verified through experiments on the gravure printed electronic platform. Finally, the coupling relationship and influence laws among multi-physical quantities of the system are analyzed. The research results show that changes in the input web tension of the multi-span system will affect the steady-state tension values of all subsequent spans. Moreover, the speed change in a roller in the multi-span system will not only affect the steady-state tension value of its own span, but also cause transient tension fluctuations in all subsequent spans. The findings of this paper provide an important theoretical basis for the research of the tension system in gravure printed electronic equipment, contributing to the enhancement of printed electronic product quality. [ABSTRACT FROM AUTHOR]

Integrating sensors and other functional parts in one device can enable a new generation of integrated intelligent devices that can perform self‐sensing and monitoring autonomously. Applications include buildings that detect and repair damage, robots that monitor conditions and perform real‐time correction and reconstruction, aircraft capable of real‐time perception of the internal and external environment, and medical devices and prosthetics with a realistic sense of touch. Although integrating sensors and other functional parts into self‐sensing intelligent devices has become increasingly common, additive manufacturing has only been marginally explored. This review focuses on additive manufacturing integrated design, printing equipment, and printable materials and stuctures. The importance of the material, structure, and function of integrated manufacturing are highlighted. The study summarizes current challenges to be addressed and provides suggestions for future development directions. [ABSTRACT FROM AUTHOR]

When using traditional 3D printing equipment to manufacture overhang models, it is often necessary to generate support structures to assist in the printing of parts. The post-processing operation of removing the support structures after printing is time-consuming and wastes material. In order to solve the above problems, a support-free five-degree-of-freedom additive manufacturing (SFAM) method is proposed. Through the homogeneous coordinate transformation matrix, the forward and inverse kinematics equations of the five-degree-of-freedom additive manufacturing device (FAMD) are established, and the joint variables of each axis are solved to realize the five-axis linkage of the additive manufacturing (AM) device. In this research work, initially, the layered curve is obtained through the structural lines of the overhang model, and a continuous path planning of the infill area is performed on it, and further, the part printing experiments are conducted on the FAMD. Compared with the traditional three-axis additive manufacturing (TTAM) method, the SFAM method shortens the printing time by 23.58% and saves printing materials by 33.06%. The experimental results show that the SFAM method realizes the support-free printing of overhang models, which not only improves the accuracy of the parts but also the manufacturing efficiency of the parts. [ABSTRACT FROM AUTHOR]

Medical images are important records to improve people's health care, and their security has become an important issue when they are transmitted through various media especially print and scan equipments. This paper proposes a digital watermarking method for medical images based on live QR code, DWT-SVD, Hough transform and bilinear interpolation. A live QR code including private information was embedded into the SVD blocks of LL3sub-band wavelet of medical image. Adjusting the embedding strength, a trade-off between invisibility and robustness was achieved. We printed and scanned the watermarked medical image with common printers and scanners and get the watermarked images after print-scanning. In extraction method, the Hough transform was used to detect the edge of the watermarked medical image and calculate the rotation angle and scaling ratio, and bilinear interpolation was used to correct geometric distortion of watermarked image. Then we extracted live QR code from corrected image successfully. Experimental results indicated that the proposed method provides sufficient security for medical images against print and scan attacks. [ABSTRACT FROM AUTHOR]

The tribotechnical properties of the Cu–(4–6) wt.% Ni–(1–1.5) wt.% Ti–(7–10) wt.% Al–(0.5–0.8) wt.% Si‒(5–8) wt.% CaF2 antifriction composite were studied. The effect of tribofilms that form and evolve in the friction process in air at loads of 2.0 MPa and rotational speeds from 5,000 to 15,000 rpm on the tribological properties was analyzed. The evolution of dissipative tribofilms and the counterface occurs through a bifurcation mechanism with a transition to one of two attractors, depending directly on the high-speed loading modes. At speeds of 5,000–13,000 rpm, a continuous homogeneous lubricating layer forms on the contacting surfaces. Electron microscopy and elemental mapping of the tribofilm confirmed that the distribution of elements was uniform, promoting high antifriction properties and a sustained self-lubrication mode. With increase in the rotational speed to 15,000 rpm, the system exhibits a self-organization effect in the formation of a coarse heterogeneous tribofilm. This tribofilm loses its continuity and is an accumulation of phases, leading to a sharp decline in antifriction properties. The dual formation of tribofilms is decisively influenced by operating conditions, particularly the intensity of external energy. Depending on this energy, tribofilms show different structures and manifest in two functionally opposite types, transforming from antifriction films to friction ones, resulting in significantly different tribotechnical properties. Copper-based antifriction composites can be recommended as an effective alternative to cast bronzes for operation at rotational speeds of 5,000–13,000 rpm and loads of 2.0 MPa in the friction units of forming, printing, and offset cylinders in high-speed printing equipment. [ABSTRACT FROM AUTHOR]

Inkjet printing technology is an emerging manufacturing technique for OLED display devices, where changes in droplet volume after continuous printing are a common issue. Changes in ink properties and disturbances from external environmental factors inevitably lead to variations in droplet volume, which may result in printing defects. Therefore, it is necessary to monitor the volume of droplets during production to ensure they meet production requirements. However, existing techniques for measuring droplet volume are time‐consuming and cannot complete the inspection of all nozzles within a limited time interval. This paper proposes a droplet volume distribution detection method based on Bayesian Theorem. By acquiring historical droplet volume data from the nozzles to design a prior distribution, and inspecting a subset of nozzle volumes, the posterior distribution of ink droplet volume is derived using Bayesian Theorem in conjunction with the prior distribution. Finally, the accuracy of this method was verified on the NEJ‐PR200 inkjet printing equipment. The results show that after sampling 10% of the nozzles, the estimated distribution trend is consistent with the actual situation, and after sampling 20% of the nozzles, the estimation error is less than 3% in the mean volume of ink droplets. Moreover, as the number of samples increases, the accuracy of the estimation also gradually improves. [ABSTRACT FROM AUTHOR]

As the hottest display technology today, OLED devices have been widely used in mobile devices, flexible displays, and other fields. Encapsulation layer film as a protective layer for OLED devices, its current manufacturing technology faces great challenges. The main reason for the challenges is the high cost and low efficiency of current manufacturing technologies. Electrohydrodynamic atomization printing (EHDAP), a low‐cost technology for the rapid manufacture of large‐area films, is up and coming for OLED encapsulation film manufacturing. In this paper, the manufacturing process of EHDAP is investigated for organic layer encapsulation film manufacturing. Multiple spray modes of organic layer encapsulated film solutions were investigated. The effect of printing states in different modes on fabricating organic layer encapsulated films was analyzed. The process phase diagram intervals are given for determining the boundaries of the steady injection state. Further production of organic layer encapsulation film with 95.7% uniformity based on self‐developed printing equipment. The theoretical and experimental studies in this paper pave the way for further development of EHDAP in OLED displays. [ABSTRACT FROM AUTHOR]

Environmental concerns within the 3D printing industry have attracted interest in processing biodegradable, eco-friendly materials. Cellulose is the most abundant natural polymer on the planet. Cellulosic pulp, derived from biomass, can be dissolved in eco-friendly solvents such as N-methyl morpholine N-oxide (NMMO) to produce lyocell. Lyocell has had applications in the textile industry for the last decade. It has shown promise in producing high-quality cellulosic fibers and the ability to be altered, tailored, and manufactured with ease. Despite this, additive manufacturing using cellulose is still an area of research with ample room to grow. In this work, we propose an in-depth study of using lyocell to manufacture 3D-printed parts using an affordable desktop 3D-printer modification. The 3D printing process of lyocell is completely circular as the solvent can be recovered from 3D-printed parts. The design of the developed 3D printing equipment, the rheological properties, and the 3D printing of the cellulose-NMMO solution are discussed in this work. Extrudate swell, filament distortion and NMMO diffusion in the regeneration process were key experimental factors to control interlayer adhesion and 3D print quality. [ABSTRACT FROM AUTHOR]

As three‐dimensional (3D) printing becomes increasingly common in radiation oncology, proper implementation, usage, and ongoing quality assurance (QA) are essential. While there have been many reports on various clinical investigations and several review articles, there is a lack of literature on the general considerations of implementing 3D printing in radiation oncology departments, including comprehensive process establishment and proper ongoing QA. This review aims to guide radiation oncology departments in effectively using 3D printing technology for routine clinical applications and future developments. We attempt to provide recommendations on 3D printing equipment, software, workflow, and QA, based on existing literature and our experience. Specifically, we focus on three main applications: patient‐specific bolus, high‐dose‐rate (HDR) surface brachytherapy applicators, and phantoms. Additionally, cost considerations are briefly discussed. This review focuses on point‐of‐care (POC) printing in house, and briefly touches on outsourcing printing via mail‐order services. [ABSTRACT FROM AUTHOR]

Recently, material extrusion (MEX) 3D printing technology has attracted extensive attention. However, some high-performance thermoplastic polymer resins, such as polycarbonate (PC), cannot be processed by conventional MEX printing equipment due to poor processing performance. In order to develop new PC-based printing materials suitable for MEX, PC/poly(butylene adipate-co-terephthalate) (PBAT) blends were prepared using a simple polymer blending technique. It was found that the addition of PBAT component significantly improved processing performance of the PC, making the blends processable at 250 °C. More importantly, the PC was completely compatible with the PBAT, and the PBAT effectively reduced the Tg of the blends, endowing the blends with essential 3D printing performance. Furthermore, methyl methacrylate-butadiene-styrene terpolymer (MBS) was introduced into the PC/PBAT blends to improve toughness. SEM observations demonstrated that MBS particles, as stress concentration points, triggered shear yielding of polymer matrix and absorbed impact energy substantially. In addition, the MBS had little effect on the 3D printing performance of the blends. Thus, a PC/PBAT/MBS blend system with favorable comprehensive mechanical properties and 3D printing performance was achieved. This work can provide guidance for the development of novel MEX printing materials and is of great significance for expanding the variety of MEX printing materials. [ABSTRACT FROM AUTHOR]

Three-dimensionally printed phantoms are increasingly used in medical imaging and research due to their cost-effectiveness and customizability, offering valuable alternatives to commercial phantoms. The purpose of this study was to assess the computed tomography (CT) attenuation characteristics of 27 resin materials from Formlabs, a 3D printing equipment and materials manufacturer. Cube phantoms (both solid and hollow constructions) produced with each resin were subjected to CT scanning under varying tube current–time products with attenuation measurements recorded in Hounsfield units (HU). The resins exhibited a wide range of attenuation values (−3.33 to 2666.27 HU), closely mimicking a range of human tissues, from fluids to dense bone structures. The resins also demonstrated consistent attenuation regardless of changes in the tube current. The CT attenuation analysis of FormLabs resins produced an archive of radiological imaging characteristics of photopolymers that can be utilized to construct more accurate tissue mimicking medical phantoms and improve the evaluation of imaging device performance. [ABSTRACT FROM AUTHOR]

The object of research is computerized polygraphic systems, their technologies, current development trends and prospects for application in modern polygraphic production. The study solves the problem of determining current trends in the field of computerized printing systems, as well as developing forecasts for their future, taking into account modern technological innovations and the possibility of their application in printing. It was determined that the modern world is experiencing rapid technological changes. The integration of computer technologies in various branches of production not only optimizes processes, but also opens up new opportunities for development and innovation. The results were obtained: it was found that computerized polygraphic systems are becoming more and more widespread, providing the opportunity to improve product quality, reduce production costs and increase productivity. It has been proven that modern printing technologies demonstrate an impressive dynamic of progress, taking place in the context of intensive development of information and communication industries. The printing industry adapts quickly, assimilating modern technological advances and immediately implementing them into the production process. It has been confirmed that computer printing systems are actively developing, responding to the increase in market requirements and contributing to the improvement of print quality. Today’s technologies, including 3D and 4D printing, digital stencil technology, laser engraving and central print management system (CPMS), are already integrated into the printing industry, providing automation, precision and efficiency. The obtained research results make it possible to ensure the industrial production of more individual, multifunctional and flexible products, expanding the horizons for printing companies. Forecasting the development of technologies and their application in printing production allows companies to always be one step ahead of competitors, rationally invest in innovation and effectively respond to changing market conditions. Given the globalization of the market and the growing demands for the quality of printing products, the ability to anticipate future trends and adapt to them is becoming a key success factor for manufacturers. [ABSTRACT FROM AUTHOR]

As an extension of 3D printing technology, 4D printing technology can change the structure, shape and function of printed materials over time, transforming printed materials from a static to a dynamic structure. As an emerging digital production technology, 4D printing technology was mainly applied in the medical and industrial fields at its early stage. In recent years, 4D printing technology has gradually found applications in the food field. New foods with higher nutritional value and better sensory quality can be designed and produced using 4D printing. This paper reviews the principle, influential factors and printing equipment of 4D printing technology and summarizes recent progress on 4D printing technology in the food field and its advantages. Finally we conclude this review with an outlook on the future of 4D food printing technology. We hope that this review can provide a reference for research on 4D printing technology for food applications.

Aiming at the problem that the additive manufacturing of large-scale components is limited by the volume of the cavity of processing equipment. In this paper, the 3D printing mode of mobile sewing combined with machine vision is proposed. Firstly, the mobile printing robot experimental platform is built based on Delta 3D printer and three-wheel omnidirectional car, and the distributed control system of mobile 3D printing robot is developed. Then, according to the mobile seam filling technology and model segmentation strategy, OpenCV software is used to define the robot hand-eye calibration and image processing method, and the visual information is mapped to the printing path planning. Finally, according to the design scheme, the printing experiment of large size mobile sewing is carried out. The equipment has been successfully applied to students' innovative practice, providing a more applicable and extensible method for additive manufacturing of large-scale components. [ABSTRACT FROM AUTHOR]

The identification of the printing equipment by examining only the printed product has been and will be one of the most important challenges for forensic experts who want to provide new possibilities for document examination in the fight against crime. For this purpose, the method of identifying RICOH xerographic printers was studied by examining the grids of yellow dots embeded on the printed documents. In the case of colour prints, the manufacturer of xerographic printers RICOH embed a yellow dots code that contains information that makes it possible to establish the serial number of the equipment used. [ABSTRACT FROM AUTHOR]

This paper reports on the development of a specialized inkjet printing head and equipment for high-resolution printing of QD dispersed inks. First, to achieve a robust process, we proposed an inkjet head design compatible with higher ink viscosity and with an ink circulation system to avoid particle aggregation. Further, we introduce a multi-restrictor inside the head to minimize ink fluid pumping pulsations on the print head and a drive-pernozzle technology with individual nozzle waveform control. Results include down to 0.8 pL ± 1.8% droplet variation across all nozzles, with a three-sigma accuracy 1.0 µm for droplet landing position. By combining optimized ink, inkjet head, and equipment technology, we successfully fabricated color converter-type micro-LED display panels. [ABSTRACT FROM AUTHOR]

Indoor particle release from toner printing equipment (TPE) is a major health concern and has received wide attention. In this study, nine printing centers were randomly selected and three working phases were simulated, namely, non-working, normal printing/copying, and heavy printing/copying. The dynamics of the ozone (O 3), volatile organic compound (VOC), and particle emissions from TPE were determined by portable detectors. Results showed that particles, VOCs, and O 3 were indeed discharged, and particles and VOCs concentrations remained at high levels. Among them, 44% of the rooms represented high-level particle releases. Submicrometer-sized particles, especially nanoparticles, were positively correlated with VOCs, but were inversely proportional to the O 3 concentration. Four elements, Ca, Al, Mg and Ni, were usually present in nanoparticles because of the discharge of paper. Si, Al, K, Ni and Pb were found in the submicrometer-sized particles and were consistent with the toner composition. The potential particle precursors were identified, which suggested that styrene was the most likely secondary organic aerosol (SOA) precursor. Overall, the use of the toner formulation and the discharge of paper attribute to the TPE-emitted particles, in which styrene is a specific monitoring indicator for the formation of SOA. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department 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.)

Printed electronics is a new technology for manufacturing electronic products. However, the existing printing technologies could not meet the requirements for high precision of printing as required for producing silicon microelectronic devices. A regulation method is proposed to solve the problem of forming precision control of the pattern in gravure printing electronics. Based on the Navier-Stokes equations and Continuity equation for Newton flow, the relationship between ink flow velocity and scraper pressure change is studied. Thus, the coupling effect of cell ceiling, scraper shape and ink is analyzed by numerical decoupling method. ANSYS CFX is used to simulate the velocity of the ink transferring process. The scraper deformation and ink film thickness uniformity were tested and measured. According to the simulation and test results, the model is modified. Research findings: Under the printing pressure, the deformation in the middle of the doctor blade is slightly lower than that at both ends. When the initial printing pressure is constant, most ink uneven streaks appear at 1/2-1/3 of the doctor blade. It is shown that increasing the initial angle of the scraper can improve the printing precision of the gravure printing electronic equipment via the reasonable matching of the initial angle by the roller scraper pressure. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) printing of metals is generally achieved via laser or electron beam melting of powder beds, and the technology has progressed well over the past decade. However, powder bed fusion (PBF) has some challenges, such as limited control over the evolution of microstructure, and the technique is unable to print metal-nonmetal components. Also, due to the high-energy beam system and stringent environmental conditions, printing equipment and corresponding maintenance costs of PBF are high. To address these limitations and challenges, here we demonstrate the printing of various metals and dissimilar material interfaces using direct ink writing-based 3D printing. Several material systems comprising copper, copper-iron, and copper-graphene are printed using metal powder inks stabilized with small concentrations of nanoclay as a rheology modifier, and the sintered 3D metallic and multi-material parts show desirable mechanical and electrical properties. The printing process and post-sintering have been done in succession to obtain complex architecture from metals and dissimilar metal–metal, metal-nonmetal interfaces. The technique allows vast flexibility in multi-material metal printing, which could lead to various applications involving hetero-interfaces between different materials. [ABSTRACT FROM AUTHOR]

Three-dimensional printing technology enables the personalization and on-demand production of edible products of individual specifications. Four-dimensional printing technology expands the application scope of 3D printing technology, which controllably changes the quality attributes of 3D printing products over time. The concept of 5D/6D printing technology is also gradually developing in the food field. However, the functional value of food printing technology remains largely unrealized on a commercial scale due to limitations of printability and printing efficiency. This review focuses on recent developments in breaking through these barriers. The key factors and improvement methods ranging from ink properties and printer design required for successful printing of personalized foods (including easy-to-swallow foods, specially shaped foods, and foods with controlled release of functional ingredients) are identified and discussed. Novel evaluation methods for printability and printing precision are outlined. Furthermore, the design of printing equipment to increase printing efficiency is discussed along with some suggestions for cost-effective commercial printing. [ABSTRACT FROM AUTHOR]

The accuracy and repeatability of the color reproduction in print is determined by the fine‐tuning of the tone reproduction curves of the basic printing colorants (most often this is CMYK). However, the diversity of manufacturers of printing equipment and dyes introduces an element of significant uncertainty about color uniformity. In addition, the traditional approach does not take into account the effect of hue change when applying the original dyes, as well as the nonlinearity of the hue rise in high‐ and low‐density areas. Determining the color of base colorants that produces the most uniform tone change is an important engineering challenge. Previously, there was no scientific basis for such calculations. We recently proposed an alternative color correction model based on gradation trajectories as an analogue of gradation curves in the CIE Lab space. We have also described the extension of the approach to double color overlay (gradation surfaces) and its analytical and discrete implications. The trajectories are the geodetic lines on gradation surfaces. In this paper, we propose using the gradation trajectories to determine "ideal" or "true" initial printing dyes for electrophotography. To simplify calculations, natural color discretization in digital printing is used. [ABSTRACT FROM AUTHOR]

The plastic waste composite molding tool with coconut fiber is designed with the aim of converting HDPE plastic waste, especially drink bottle covers mixed with coconut fiber into a product in the form of a composite board (panel) that is more useful. The dimensions of the mold are 410 x 540 mm, the tool height is 850 mm, the width is 600 mm, the length is 600 mm, the temperature of the installed heating elements is around 200-250 degrees for 12 pieces, 220 V 1000 watts, while the press uses a 10 ton hydraulic jack. While the heating temperature for pressing the composite board is set in the range of 130 – 180 oC. From the results of the first printing press with iron plate material, the resulting product is sticky on the plate surface, the second test is coated with aluminum foil, the resulting product is less than perfect because the surface is uneven. , while the third test was coated with a stainless steel plate, the resulting product was better than the previous results. This research needs to be improved in order to assist the government in handling plastic waste. In addition, the results of products with this tool will help improve people's skills and improve the economy of the products of this tool.

The traditional construction technology not only has environmental friendly problems such as noise and dust but also has resource-saving problems such as large template quantity and low construction accuracy. In addition, the traditional construction technology has an insurmountable technical bottleneck in the construction of special-shaped buildings. Building 3D printing technology can effectively overcome many problems existing in traditional construction technology and provide unlimited possibilities for the construction of special-shaped buildings. Concrete 3D printing technology is one of the most important technical categories of building 3D printing. In this study, the research status and progress of concrete 3D technology were reviewed from the aspects of equipment system, materials, defect control, and application scenarios. On this basis, the development foreground was prospected. [ABSTRACT FROM AUTHOR]

Several recent studies have attempted to formulate printable cementitious materials to meet the printing requirements, but these materials are designed to work with specific printing equipment and printing configurations. This paper aims to systematically develop and perform characterization of a commercially available ultra-high-performance concrete-class material (UHPC) modified to be printable. Four percentages of superplasticizer were used (100%, 94%, 88%, 82%) to adjust the UHPC mixture for 3D-printing requirements. A superplasticizer amount of 88% was considered adequate to meet the requirements. Several fresh and hardened properties of UHPC were measured experimentally: shape-retention ability and green strength were investigated in fresh state, and compressive and flexural strength were evaluated in three loading directions to evaluate the anisotropic effects. Furthermore, the strength of the interlayer bond was investigated. The UHPC developed in this study met the criteria for extrudability, buildability, and shape retention to ensure printability. In comparison with mold-cast UHPC, printed UHPC exhibited superior flexural performance (15–18%), but reduced compressive strength (32–56%). Finally, the results demonstrated that a commercially available UHPC-class material can be used for 3DCP, which possesses all necessary properties, both fresh and hardened. [ABSTRACT FROM AUTHOR]

As the main component of the 3D printing industry, the fused deposition process covers all aspects of the industry with its advantages of low R&D investment, high practicability, and open source programs. However, due to process problems, problems have arisen in terms of printing efficiency and molding quality. To this end, we designed a large-scale multinozzle FDM printing device using the high-current fused deposition (FDM) printing principle. The defects of small size, slow printing speed, and low precision are deeply studied, and the machine structure is optimized according to the structural strength analysis. In this paper, the theoretical design and static analysis of the overall mechanical part of the large-scale FDM device are carried out, and then, the selection of the movement organization structure and movement method is theoretically analyzed. A modular flow chart is designed for the control system to coordinate and control the parallel and precise operation of multiple nozzles, and the relationship function between the main controller, power driver, and heating module is designed. By modifying the firmware parameter command, we can find out the optimal method running on the platform and discuss the function usage of the slicing software in detail. According to the current problems of FDM printing equipment, various factors affecting printing speed were analyzed from the perspective of printing accuracy, and the process parameters of 3D printer were studied through orthogonal experiments. Speed, nozzle temperature, idling speed, and fill rate were studied, and the relationship between factors affecting printing speed and printing accuracy was obtained. Use a simple model print to measure the overall performance of your product. The stability of the system is verified by short-term and long-term printing tests. The analysis results show that the forming performance and stability of the large-scale FDM are improved significantly. [ABSTRACT FROM AUTHOR]

The paper examines variation in the structure and properties of an antifriction composite produced from grinding waste of the R6AM5 high-speed steel with additives of CaF2 solid lubricant depending on the quantitative composition of the main components. The composite is intended to perform in friction units of offset and press cylinders of printing machines that operate in self-lubrication conditions at high rotation speeds (up to 5,000 rpm) and increased loads (up to 5 MPa) in air. The developed production modes allowed the R6AM5 steel grinding waste composite to be appropriately structured. The composite structure is a metal matrix in which CaF2 solid lubricant particles are evenly distributed. The composite's metal matrix consists of pearlite–carbide and carbonitride phases formed in the presence of R6AM5 steel doping elements. The appropriate amount of the CaF2 solid lubricant, which contributes to reaching the maximum antifriction properties, was determined by a series of experimental mechanical and tribotechnical tests and by fractographic analysis of the materials containing from 3.0 to 10.0 wt.% CaF2. The microstructural, fractographic, mechanical, and tribotechnical tests showed that content of the CaF2 solid lubricant that ensured high mechanical properties and significantly increased the antifriction characteristics of the composites varied from 4.0 to 8.0 wt.%. Electron microscopy studies of the friction surfaces of the R6AM5 + (4.0–8.0)% CaF2 composites confirmed the formation of uniform continuous protective antifriction films that completely covered the contact pair's friction surfaces and provided self-lubrication. Field tests showed the feasibility of using antifriction bushings made of the new composites produced from R6AM5 steel grinding waste and (4.0−8.0)% CaF2 in the friction units of offset and press cylinders of roll newspaper offset printing machines. The research identified prospects for expanding studies over a wide range of valuable metal waste for the development of new effective antifriction composites with a well-grounded content of components. This would also make another important contribution to protecting the environment against contamination. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department 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 growing use of 3D printing in the biomedical sciences demonstrates its utility for a wide range of research and healthcare applications, including its potential implementation in the discipline of breath analysis to overcome current limitations and substantial costs of commercial breath sampling interfaces. This technical note reports on the design and construction of a 3D-printed mouthpiece adapter for sampling exhaled breath using the commercial respiration collector for in-vitro analysis (ReCIVA) device. The paper presents the design and digital workflow transition of the adapter and its fabrication from three commercial resins (Surgical Guide, Tough v5, and BioMed Clear) using a Formlabs Form 3B stereolithography (SLA) printer. The use of the mouthpiece adapter in conjunction with a pulmonary function filter is appraised in comparison to the conventional commercial silicon facemask sampling interface. Besides its lower cost – investment cost of the printing equipment notwithstanding – the 3D-printed adapter has several benefits, including ensuring breath sampling via the mouth, reducing the likelihood of direct contact of the patient with the breath sampling tubes, and being autoclaveable to enable the repeated use of a single adapter, thereby reducing waste and associated environmental burden compared to current one-way disposable facemasks. The novel adapter for breath sampling presented in this technical note represents an additional field of application for 3D printing that further demonstrates its widespread applicability in biomedicine. [ABSTRACT FROM AUTHOR]

Additive technologies are widely used in various industries. However, nowadays, the large-scale implementation of these technologies in the construction industry is difficult, due to a lot of open practical and scientific questions in terms of both building mixtures and 3D printing equipment. When performing studies focused on the development of cost-effective mixtures based on readily available raw materials for building extrusion 3D printing, it was found that the final result was determined by the rheology of the building mixture, the speed of the screw, and other factors. The article studied the combined effect on the extrusion of the building mixture and the parameters of the printed track of such factors as the thickness of the layer, the linear printhead traversed velocity of the forming device, and the speed of rotation of the screw. We aimed to establish relationships between the above factors, providing an increase in the stability of the printing process and the quality of the resulting structure. To carry out the research, an experimental program and original methods were developed, involving printing in different regimes using a laboratory construction 3D printer. Based on the regression analysis of the data obtained, it was found that the process of 3D printing by extrusion methods cannot be described by a linear function. It was found that a change in the linear speed of the nozzle movement can increase the yield of the mixture, and also lead to track stretching and the degradation of some parameters. The boundary value, in this case, is the layer thickness of 0.77–0.8 of the nozzle width. The response of the system to changes in the linear printhead traversed velocity and the frequency of rotation of the screw occurs in different ways. A change in the linear printhead traversed velocity at the optimal height of the layer has a slight effect on its width. Reducing the speed of rotation of the screw leads to a decrease in the overall dynamics of the mixture flow and an increase in its viscosity due to its thixotropic nature. When the previous speed of rotation of the mixture is restored, the dynamics of the flow are restored with a noticeable delay. In general, this is recommended to ensure the highest dynamics of the printing process. For the laboratory construction 3D printer and the building mixture used in the article, the regime with the following parameters was recommended: a linear printhead traversed velocity of 900 mm/min; an extruder frequency of 25 rpm; and a relative layer thickness of 0.8 (of the nozzle width). This regime provides the optimal ratio of performance/quality and the stability of track parameters. [ABSTRACT FROM AUTHOR]

The purpose of this study is to show more diverse texture modifications by changing the material of a food 3D-printed structure conducted only with soft materials (in this case, potatoes and chocolate) to a hard material (in this case, maltitol here). However, unlike previous 3D-printed food materials, sweetener materials such as sucrose and maltitol are sensitively caramelized at a high melting temperature. As such, there is no commercialized printing equipment. Therefore, a printing process experiment was conducted first in this case. To do this, a high-temperature syringe pump-based extrusion device was designed, and process tests according to the temperature and environment were conducted. An assessment of the internal structural changes according to the infill patterns and infill percentages was conducted based on the acquired process conditions. The texture strength increased as the infill percentage increased. Depending on the infill patterns, the texture strength increased in the order of the Hilbert curve, honeycomb, and rectilinear samples here. As a result, a change in the texture strength was determined through a change in the internal structure of a hard food material using 3D printing, which showed a wider range of change than in conventional soft food materials. [ABSTRACT FROM AUTHOR]

The three-dimensional (3D) printing technique for cement-based materials has been actively investigated and utilized in civil engineering. However, there is no systematic review of the fabricating devices. This paper reviews the software and hardware for extrusion-based 3D concrete printing. Firstly, a dedicated tool path generating software is urgently needed to meet the cementitious printing applications and to improve printing quality with toolpath optimizations. Secondly, the existing printing equipment was summarized and discussed, concluding the pros and cons of various 3D motion systems, material systems, and nozzle units. Suitable choices for scientific research and engineering applications were recommended. The reinforcing techniques were categorized and concluded with the existing drawbacks and the research trend. A hybrid manufacturing system of 3D printing and the reinforcing technique was then proposed with a system diagram and flowchart. [ABSTRACT FROM AUTHOR]

Based on STL (stereo lithography) format file and with Microsoft Visual C++ 6.0 programming language, a 3D printing slicing software appropriate for the surface strengthening of the parts has been developed, which includes three functions: 3D model import, model slicing and data export. Through the grouping of STL model triangle facets before slicing, the judgment times of the relationship between the triangle facets and the cutting planes are reduced, and the slicing efficiency is improved. Aiming at the fact that the surface should be strengthened when the part is formed by using of 3D printing process, the function of identifying and marking the surface of the geometric entity is accomplished in the slicing software, which can strengthen the surface of the part according to the user's requirements. The developed slicing software can provide an entity slicing file for 3D printing equipment. The related functions can be adjusted and improved according to user's needs, which makes the software convenient and flexible to use. [ABSTRACT FROM AUTHOR]

To ensure a successful outcome when using cementitious materials during three-dimensional (3D) printing operations, the effects of chemical admixtures on rheological and setting behavior must be carefully adjusted to accommodate the needs for pumping, extrusion, deposition, and self-sustainability without the support of formwork. This paper highlights potential solutions offered by chemical admixtures, while discussing various testing methods and important influencing parameters. The impact of commercial polymers on viscosity, initial yield stress, thixotropy, and their variations over time are reported. Influencing factors, such as mixing energy and material interactions, are discussed. Accelerating and strength-enhancing admixtures are used to illustrate the adjustment of setting and early strength development of concrete. Understanding the possibilities of modifying fresh concrete properties will help to improve the robotic construction process as well as the design or adaptation of the printing equipment. [ABSTRACT FROM AUTHOR]

Copyright of China Mechanical Engineering is the property of Editorial Board of China Mechanical Engineering 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.)

This study used flexible polymer materials in large-area roll printing to control the curvature feature size of the microstructure mold array of polydimethylsiloxane (PDMS) through system-developed equipment and gas-assisted molding processing. It designed and developed special roll printing equipment for curvature-adjustable flexible polymer mold for a series of tests regarding material mechanical properties. Mold, wear characteristics, and mechanical property parameters were obtained for experimental simulation, where the optimal parameters of microstructure mold forming with gas-assisted control were simulated. The simulation results were consistent with those in actual roll printing. The preliminary optical testing and applications were carried out, and verified that the innovative continuous roll printing process can obtain good large-area array forming structures. [ABSTRACT FROM AUTHOR]

The use of orthotic-prosthetic devices is the gold standard for the treatment of limb diseases and traumas, especially in the postoperative or rehabilitation phases. In non-permissive scenarios, such as today's operating theatres, the production of these devices using traditional methods represents a major challenge. The introduction of 3D printing technology, coupled with positions as orthopaedic technician within the Armed Forces organisation could be an effective and efficient solution to guarantee an adequate quality of care, even in remote areas. Both for deployed military personnel and the local population would benefit from it. In addition, the wide choice of printing systems and materials would better meet the local needs. Potential advantages include high precision and compliance with the most complex geometries, a lighter logistics chain, and close contact with the patient during the educational, rehabilitation, and adaptive phases. Longer production times and the cost of 3D printing equipment, on the other hand, could be the main obstacles. [ABSTRACT FROM AUTHOR]

At present, 3D printing technology is becoming more and more popular, but the traditional learning method has some limitations. The price of 3D printing equipment is expensive, and there are some security risks in the process of learning operation. This paper mainly introduces the development and process research of high-temperature environmental protection metal 3D printing equipment and realizes the design of 3D printing equipment combined with virtual reality technology. In this paper, the whole system of 3D printing equipment is designed and built. The function of motion platform and substrate in mechanical system is analyzed, and the detailed structure design is carried out; the control principle of control system including motion control system and temperature control system is introduced in detail, and the corresponding design and construction work is carried out. In this paper, the pure tin wire with low melting point was used as the experimental material, and the mechanical properties and microstructure of the metal tin forming parts were analyzed. On the basis of tin formation experiment, metal deposition experiment and metal forming error experiment were carried out with H65 high melting copper wire as the raw material. The experimental results show that when the printing speed is 35/mm, the dimensional accuracy of the products is high; the microhardness of the printed tin is close to that of the original material, the surface hardness is 12.50HV0.05, and that of the copper alloy is 14.31HV0.05; the tensile strength of tin wire after melt deposition is slightly reduced after tensile test for the machined tin parts, the ultimate tensile strength of the first group of specimens is reduced by 1.58%, and that of the second group is reduced by 0.74%. This paper combines virtual reality technology with 3D printing technology and develops 3D printing equipment for high-temperature environmental protection metal using virtual reality technology. The forming and printing performance of the device is analyzed theoretically and experimentally. The experimental results verify the feasibility of the system and the practicability of the device. [ABSTRACT FROM AUTHOR]

In this paper, electro-hydraulic coupling jet printing technology based on the Weissenberg effect is put forward for the first time, and the pulse voltage is used to realize the on-demand printing. The experimental results show that the Weissenberg effect can inhibit the solution reflux and make the solution converge into a cone tip at the nozzle, which is more conducive to position printing precisely. By exploring the influence principles of process parameters on printing, it is found that droplet diameter is positively correlated with rotation speed and negatively correlated with voltage frequency. The printing frequency is negatively correlated with the rotation speed and positively correlated with the voltage frequency. However, the effect of voltage amplitude and duty ratio on the printing effect is not obvious in a certain range. It is found that the rotation speed of needle core within the range of 1800 r/min-7500 r/min can print out the ideal lattice structure, which proves the feasibility of this system to realize on-demand positioning printing. Finally, by using the printing equipment, the sacrificial layer structure of PDMS microfluidic chip was successfully made and the function of the microfluidic chip was realized, which further verified the practicability of the technical scheme proposed in this paper. [ABSTRACT FROM AUTHOR]

Purpose: The dimensional accuracy of three‐dimensional (3D) printed anatomical models is essential to correctly understand spatial relationships and enable safe presurgical planning. Most recent accuracy studies focused on 3D printing of a single pathology for surgical planning. This study evaluated the accuracy of medical models across multiple pathologies, using desktop inverted vat photopolymerization (VP) to 3D print anatomic models using both rigid and elastic materials. Methods: In the primary study, we 3D printed seven models (six anatomic models and one reference cube) with volumes ranging from ~2 to ~209 cc. The anatomic models spanned multiple pathologies (neurological, cardiovascular, abdominal, musculoskeletal). Two solid measurement landing blocks were strategically created around the pathology to allow high‐resolution measurement using a digital micrometer and/or caliper. The physical measurements were compared to the designed dimensions, and further analysis was conducted regarding the observed patterns in accuracy. All of the models were printed in three resins: Elastic, Clear, and Grey Pro in the primary experiments. A full factorial block experimental design was employed and a total of 42 models were 3D printed in 21 print runs. In the secondary study, we 3D printed two of the anatomic models in triplicates selected from the previous six to evaluate the effect of 0.1 mm vs 0.05 mm layer height on the accuracy. Results: In the primary experiment, all dimensional errors were less than 1 mm. The average dimensional error across the 42 models was 0.238 ± 0.219 mm and the relative error was 1.10 ± 1.13%. Results from the secondary experiments were similar with an average dimensional error of 0.252 ± 0.213 mm and relative error of 1.52% ± 1.28% across 18 models. There was a statistically significant difference in the relative errors between the Elastic resin and Clear resin groups. We explained this difference by evaluating inverted VP 3D printing peel forces. There was a significant difference between the Solid and Hollow group of models. There was a significant difference between measurement landing blocks oriented Horizontally and Vertically. In the secondary experiments, there was no difference in accuracy between the 0.10 and 0.05 mm layer heights. Conclusions: The maximum measured error was less than 1 mm across all models, and the mean error was less than 0.26mm. Therefore, inverted VP 3D printing technology is suitable for medical 3D printing if 1 mm is considered the cutoff for clinical use cases. The 0.1 mm layer height is suitable for 3D printing accurate anatomical models for presurgical planning in a majority of cases. Elastic models, models oriented horizontally, and models that are hollow tend to have relatively higher deviation as seen from experimental results and mathematical model predictions. While clinically insignificant using a 1 mm cutoff, further research is needed to better understand the complex physical interactions in VP 3D printing which influence model accuracy. [ABSTRACT FROM AUTHOR]

As a key component of satellite flexographic printing equipment, the vibration characteristics of the central impression cylinder have an important effect on the product quality. In order to improve dynamic characteristic of the central impression cylinder, the modal analysis on the central impression cylinder is carried out in combination with finite element software in this paper. Then, the modal properties are systematically compared between the central impression cylinder with circulating cooling water and without. The results show that the natural frequency of the central impression cylinder is greatly reduced based on the fluid–solid coupling method. Simultaneously, the natural frequencies and mode shapes of the central impression cylinder based on the finite element analysis are verified by an experimental test. The simulation results are in good agreement with the experimental results, indicating the effectiveness of the finite element model and experimental method used in this study. [ABSTRACT FROM AUTHOR]

The integration of high-resolution conductive structures into polymer devices using a low-cost, rapid, and accurate manufacturing technique is important for the future of the microfluidic, photovoltaic, flexible printing, and organic electronics industries. In this study, the microcontact printing (μCP) of high-resolution conductive patterns on polymer substrates using silver nanoparticle inks and a roll-based printing equipment was empirically investigated. A process model was developed to predict the quality of the printed patterns (defined as thickness and coverage ratio) from known printing parameters, based on the statistical analysis of a set of carefully designed experiments that were informed by theoretical understanding of the μCP process. The statistically relevant variables in the process model for the pattern thickness were ink solids loading, ink viscosity, stamp feature size, and the surface energy ratio of ink to substrate. For the coverage model, the key inputs were ink solids loading, ink viscosity, stamp feature size, and inkpad thickness. The effects of these variables on the thickness and coverage of the printed patterns were quantified by a linear model derived from an orthogonal, fractional factorial experimental design with five input factors and two outputs. The extension of the process model to predict the printing behavior of other inks and substrates, and the successful printing of conductive features on polymer substrates with 5 μm resolution, were demonstrated. [ABSTRACT FROM AUTHOR]

RGB printing method has been widely regarded as a potential tool for manufacturing high resolution, large size OLED applications, with the help of recent progresses of soluble OLED materials and ink‐jet printing equipment. However, there are still technical hurdles which remain in order for inkjet‐printed OLED displays to move from prototype to mass production scale. In this report, recent R&D trends will be reviewed of device performances, ink‐jet printing equipment, as well as inkjet‐printed OLED products recently demonstrated by display panel makers for various applications. Moreover, key technical issues will be discussed to be overcome in order for mass production, such as an ink formulation, a high resolution ink‐jet printing, inter‐mixing between printed layers, thickness uniformity of printed layers, etc. Lastly, our recent progress will be presented, of a power consumption, color gamut, and lifetime of inkjet‐printed panel with pixel resolution over 200ppi. [ABSTRACT FROM AUTHOR]

In order to make the printing process de facto standard of OLED production process, we have been originally developing solution EL materials & devices, printing processes and printing equipment with excellent productivity. At the end of 2018, we developed a high resolution printing OLED monitor (21.6 inch 4K, 204ppi) that combines these technologies, and we succeeded in commercialization for the first time in the world. [ABSTRACT FROM AUTHOR]

Background: Three-dimensional (3D) printing is a promising technology, but the limitations are often poorly understood. We compare different 3D printing methods with conventional machining techniques in manufacturing meatal urethral dilators which were recently removed from the Australian market.Methods: A prototype dilator was 3D printed vertically orientated on a low-cost fused deposition modelling (FDM) 3D printer in polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS). It was also 3D printed horizontally orientated in ABS on a high-end FDM 3D printer with soluble support material, as well as on an SLS 3D printer in medical nylon. The dilator was also machined in stainless steel using a lathe. All dilators were tested mechanically in a custom rig by hanging calibrated weights from the handle until the dilator snapped.Results: The horizontally printed ABS dilator experienced failure at a greater load than the vertically printed PLA and ABS dilators, respectively (503 g vs 283 g vs 163 g, p < 0.001). The SLS nylon dilator and machined steel dilator did not fail. The steel dilator is the most expensive with a quantity of five at 98 USD each, but this decreases to 30 USD each for a quantity of 1000. In contrast, the cost for the SLS dilator is 33 USD each for five and 27 USD each for 1000.Conclusions: Low-cost FDM 3D printing is not a replacement for conventional manufacturing. 3D printing is best used for patient-specific parts, prototyping or manufacturing complex parts that have additional functionality that cannot otherwise be achieved. [ABSTRACT FROM AUTHOR]