Even though most information is digitized today, paper as a printing substrate is still essential. The quality of the paper depends on whether it has the properties required for its intended use, ...which will fundamentally rely on the raw materials used. Nowadays, the production of paper and board is increasingly focused on alternative non-wood raw materials. In this context, the main objective of this research is to improve the quality of prints on laboratory-made papers with supplementary barley pulp by coating the surface of the papers with titanium dioxide coating. Since laboratory-made papers were not subjected to the bleaching process and no additional surface treatments were used, TiO2-based coating proved to be one of the ways to improve the quality of the prints on such substrates. In this study, it was concluded that TiO2-based coating did not affect the colorimetric values of the black prints to the extent that it affected the colorimetric values of the magenta prints. However, density of printed inks was increased up to 14% for prints on laboratory-made papers with higher amount of barley pulp and TiO2-based coating in two layers.
Spreading and absorption of small liquid drops on porous substrates is of interest in a number of fields ranging from additive manufacturing and composite processing to inkjet printing. In inkjet ...printing, spreading and absorption processes determine the final area of a printed dot, which is decisive for print quality in terms of coverage and resolution. However, it is not fully understood how substrate and liquid properties influence the involved physical processes and the resultant printed dot area. In this work, the printed dot area of overall 140 paper-liquid pairings representative for the operational window of an inkjet printer is evaluated. The results are explained by a simple model including spreading, absorption, and evaporation. The surface tension and viscosity of the liquids, as well as the pore size and polarity of the substrates were varied systematically to represent the range of uncoated paper-liquid pairings applicable for inkjet printing. Results show that the printed dot area mainly depends on the wettability of the liquid-substrate pairing followed by penetration speed. Evaporation and volume reduction due to roughness filling had little impact. The modeling results are in line with empirical observations showing that the dot area is closely related to the contact angle.
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•Evaluation of inkjet printed dots of 140 uncoated paper-liquid pairings.•Substrates and liquids were tailored to cover operation window of an inkjet printer.•Inkjet printed dot area is simulated from spreading, absorption and evaporation.•The printed dot area depends predominantly on the wetting interaction.
In this study, electrophotographic printing and inkjet printing systems were applied to some commercial A4 office papers and their effects on print quality were determined. It is to evaluate the ...print quality by determining the test parameters that measure the print quality by applying electrophotographic printing and inkjet printing systems to some commercial office papers that have determined the surface properties and optical properties supplied from the market. Print quality was measured by testing with parameters such as delta gloss 60°, print lightness, print chroma, print density. As a result of the tests determined for print quality; print density values were low in A4 office papers with high roughness and porosity values, and the specular gloss values of the samples decreased in both printing applications. In electrophotographic printing; it was determined that darker colors formed with print lightness parameter, and the color scale increases in two-sided printing with print chroma values. It was determined that the color scale of print chroma values increased in two-sided prints. It was determined that mostly some commercial office papers were positively affected by printing on one side in inkjet printing and by printing on two-sided in electrophotographic printing.
Embedded bioprinting overcomes the barriers associated with the conventional extrusion‐based bioprinting process as it enables the direct deposition of bioinks in 3D inside a support bath by ...providing in situ self‐support for deposited bioinks during bioprinting to prevent their collapse and deformation. Embedded bioprinting improves the shape quality of bioprinted constructs made up of soft materials and low‐viscosity bioinks, leading to a promising strategy for better anatomical mimicry of tissues or organs. Herein, the interplay mechanism among the printing process parameters toward improved shape quality is critically reviewed. The impact of material properties of the support bath and bioink, printing conditions, cross–linking mechanisms, and post‐printing treatment methods, on the printing fidelity, stability, and resolution of the structures is meticulously dissected and thoroughly discussed. Further, the potential scope and applications of this technology in the fields of bioprinting and regenerative medicine are presented. Finally, outstanding challenges and opportunities of embedded bioprinting as well as its promise for fabricating functional solid organs in the future are discussed.
Embedded bioprinting improves the shape quality of bioprinted constructs made up of soft materials and low‐viscosity bioinks. Herein, the interplay mechanism among the printing process parameters toward improved shape quality is critically reviewed. Outstanding applications, challenges, and opportunities of embedded bioprinting as well as its promise for fabricating functional solid organs in the future are also discussed.
The nomenclature of parts used in the production of car wiring systems for BMW, MERCEDES, SKODA and other cars at the Ukrainian-German joint venture Kromberg & Schubert has up to 10,000 names. They ...are structurally diverse, ranging from simple parts such as rods and levers to body parts with internal holes, voluminous pockets and so on. Until recently, these parts were made from different compositions of metal. In use, they lost their effectiveness over time - wear of the working surfaces or destruction. Before the pandemic, used parts were replaced by ordering them from other companies. This practice proved to be inefficient: high costs of developing prototypes, transportation and testing under production conditions. One of the most promising directions in the development of modern engineering is the development of new technologies for rapid manufacturing. The essence of such technologies is the layer-by-layer construction of products from polymer materials on the basis of CAD models - models whose three-dimensional geometry is described in digital form using solid modelling programmes (SolidWorks, CATIA, ProE, AutoCAD, etc.). Trial batches of brackets produced at the company using such technologies showed the promise of adaptive technologies.
Fused deposition modelling (FDM) 3D printing, as a supporting technology in social manufacturing and cloud manufacturing, is a rapidly growing technology in the era of industry 4.0. It produces ...objects with a layer-by-layer material accumulation technique. However, qualitative uncertainties are the common challenges yet. In order to assure print quality, studying the error causing parameters and minimizing their effects are important. This paper presents a feedback-based error compensation strategy, which integrates a fuzzy inference system and a grey wolf optimization algorithm. The objectives are twofold. First, the possible errors in FDM 3D printing are discussed in detail and optimal error causing parameters are obtained in percentage. This is used to understand the effects of the printing errors in every phase of the 3D printing process. From the nine optimization configuration trials used, Config-6 that has 100 number of iterations and 60 wolves is selected due to its higher convergence speed and best fitness value. The integral absolute error (IAE) is used as an objective function and the global minimum is achieved in the iteration interval
86
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100
. The outputs of this optimization problem are used to achieve the next objective. Second, a closed-loop quality monitoring approach comprising of inner-loops and an outer-loop is taken. The three inner-loops are used to monitor the errors during pre-printing, printing, and post-printing, respectively. The outer-loop, on the other hand, is responsible for monitoring the aggregated errors in all the three 3D printing phases. The error compensation system simulation in Matlab is run for 10 s, and the results show that the “normal” range deformation factors are reached within less than 2 s for the inner-loops, whereas the outer-loop deformation factor is achieved within 2 s. The responses are within the acceptable time range.
Aperiodic, clustered-dot, halftone patterns have recently become popular for commercial printing of continuous-tone images with laser, electrophotographic presses, because of their inherent stability ...and resistance to moiré artifacts. Halftone screens designed using the multistage, multipass, clustered direct binary search (MS-MP-CLU-DBS) algorithm can yield halftone patterns with very high visual quality. But the characteristics of these halftone patterns depend on three input parameters for which there are no known formulas to choose their values to yield halftone patterns of a certain quality level and scale. Using machine learning methods, two predictors are developed that take as input these three parameters. One predicts the quality level of the halftone pattern. The other one predicts the scale of the halftone pattern. To provide ground truth information for training these predictors, human subjects viewed a large number of halftone patches generated from MS-MP-CLU-DBS-designed screens and assigned each patch to one of four quality levels. For each patch, the location of the peak in the radially averaged power spectrum (RAPS) is calculated as a measure of the scale or effective line frequency of the pattern. Experimental results demonstrate the accuracy of the two predictors and the effectiveness of screen design procedures based on these predictors to generate both monochrome and color high quality halftone images.
3D printing technologies of construction materials are gaining ground in the building industry. As well documented in the literature, these advanced manufacturing methodologies aim to reduce ...work-related injuries and materials waste, enhancing architectural flexibility which would enable more sophisticated designs for engineering and aesthetic purposes. In this framework, the development of functional and eco-sustainable printable materials represents an extremely attractive challenge for research, promoting digital fabrication to reach its maximum cost-effective and technological potentials. The use of recycled tire rubber particles in 3D printable Portland-based compounds is an exclusive contribution in this field. This line of research aims to integrate the well-known engineering performances of rubber-cement materials with the advanced peculiarities of additive manufacturing methodologies. As an innovative contribution, the authors propose here a detailed study on the possible relationship between rubber particle size and technological properties of the 3D printable mix. Specifically, two groups of continuous size grading polymer aggregates (0-1 mm rubber powder and 1-3 mm rubber granules as fine and coarse fractions, respectively) were analyzed in terms of impact on rheology, print quality, microstructure, mechanical properties, and acoustic insulation performance. Concerning the print quality, rubber aggregates altered the fluidity of the fresh mix, improving the adhesion between the printed layers and therefore enhancing the mechanical isotropy in the post-hardening sample. A remarkable influence of the rubber gradation on the compounds’ behaviour was found in hardened properties. By comparing the rubberized compounds, the fine polymer fraction shows greater interfacial cohesion with the cement paste. However, more significant mechanical strength loss was found due to a greater reduction in density and increased porosity degree. On the other hand, mortars doped with larger rubber particles tend to have a higher unit weight, finest pore distribution, minor mechanical strength drop, and higher ductility but worse interface binding with the matrix. Regarding the acoustic insulation properties, a proper balance between rubber powder and granules in the mixes allows to obtain comparable/superior performance compared to plain mortar but the effect of the aggregate size is strongly dependent on the sound frequency range investigated. Future findings revolve around applicability studies of these formulations in civil and architectural fields, benefiting from the design flexibility of 3D printing. Doi: 10.28991/cej-2021-03091701 Full Text: PDF
The white fabric was printed with different printing temperatures and pressing times using the sublimation printing process in solid-tone black color with a 100 % total ink limiting level. ...Non-uniformity of the print was examined through print mottle determined by grey level co-occurrence matrix (GLCM) image processing method. Color strength of print was also determined by reflectance spectrophotometry. The print with the lower print mottle was obtained at a printing temperature of 190 °C at a longer pressing time of 120 s or at an increased printing temperature of up to 210 °C at the reduced pressing time of 60 s. The print with the lower print mottle had the lowest entropy, contrast, and correlation and the highest energy and homogeneity. The print with a higher color strength was accompanied by decreased print mottle. Choosing a suitable printing temperature and pressing time for sublimation printing is helpful in achieving print with low print mottle and high color strength and balancing cost, price, and price.
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