A complex technology of strengthening parts has been developed through the formation of a regular microrelief on the surface followed by chrome plating. The strengthening method was vibration rolling, which made it possible to obtain sinusoidal and hexagonal microrelief due to the correlation of processing modes. The conducted studies of the effect of complex processing of parts on quality have established the mechanism of obtaining minimum roughness. When using a vibrating tool with a radius of the deformable element R=2 mm, with a pressing force of Р=550 Н, the surface roughness is observed for a sinusoidal microrelief according to the arithmetic mean deviation Ra from 0.08 to 1.32 μm, for a hexagonal one - from 0.63 to 3, 2 μm, which is 7.5 times less without the use of strengthening methods. Due to this, it is possible to extend the operational properties, ensure the reliability of the application of complex technology followed by chrome plating. The parameters of the profile of the engraved strokes of the intaglio printing forms obtained by the method of direct laser engraving (DLE) were studied; it was found that the features of laser processing of the form material during DLE affects the roughness of the treated surfaces and creates inflows, which can affect the protective coating adhesion, the quality of the formation of the paint layer on the print, its tactile and colour properties. The studied engraved strokes differed in the designed profile, namely, the depth (60–100 μm) and the inclination angle of the stroke walls (45°; 90°). The research results give reasons to assert that all the engraved strokes of the samples have deviations from the given geometric profile (the stroke wall inclination decreases to 25°–30°), are asymmetrical, the protective PVD (Plate Vapor Deposition process) coating has insufficient adhesion to the main material of the form. The paper is devoted to the study of the effect of technological factors on geometric parameters and surface roughness.
The object of research is plastic cards. The subject of the study is to determine the effect of laser processing of the edge of plastic cards on the overall quality of the card, including the parameters of durability. The main hypothesis of the research is that the selection of optimal technological parameters of laser processing of the edge of plastic cards will lead to an improvement of their overall quality, in particular, will increase the properties of durability. The work analyzes the possible defects of plastic cards, identifies the most common defects that occur both during the production and during the operation of plastic cards. The work offers the technological processes of plastic card sample production, the methodology and the results of the study of the influence of laser processing parameters on the quality indicators of plastic cards, in particular characteristics of durability. Technological recommendations for improving the durability characteristics of plastic cards have been developed. In particular, the most optimal parameters for processing cards with a laser are given, which ensured high quality indicators, including durability of cards.
Fractal geometry with its ability of description difficult and irregular models found application in different scientific disciplines. In a field of production and polygraphic production protection understanding properties of paper with watermarks has crucial role in authentication and quality assurance. Fractal analysis gives powerful instrument for quantity description of difficult templates, which are created with watermarks on paper substrates, what gives ability to get vital information about its difficulty and uniqueness. This article is a complex research, which focuses on calculation of fractal dimension of paper surfaces with watermarks with the help of advanced methods of displaying and computational analysis. In the result we have interdependencies of fractal dimensions between measurements with different level of distance.
We have developed a model of the medium color of the image, according to which the image moves away from the viewer at a certain distance, at which all the colors of the image are mixed, forming an inseparable color spot. That is, the image is converted into a conditional pixel, which is a mixture of colors of all its pixels. Based on the proposed model, it is possible to estimate the degree of closeness of the optical characteristics of the two images by the deviation of the average color. The method of medium color was realized with a specially designed program application for Kazakh Tenge as well as for Ukrainian Hryvnia evaluation. The measurement of optical characteristics was performed in the non-printed area near the watermark on both the face and reverse of the banknotes. The results show that the evaluation of the image by the deviation of the medium color according to the developed model is a fairly accurate indicator of wear of the printed layer, has an arithmetic mean error less than traditional optical evaluation methods - brightness change and color difference. Thus, the deviation of the medium color describes the human perception of banknote soiling fairly well. This method of medium color, which aims to eliminate the subjectivity of image evaluation, can be used to process both digital images and imprints.
Billions of banknotes in their daily circulation are determined as one of the important spreading ways of thousands of different microbes among the world's population. Therefore, the main factors influencing the degree of microbiological contamination of banknotes are considered. The influence of varnishing technological parameters, in particular the type of varnish cure on the surface, anilox roll line count, and anilox roll transfer volume, on the resistance of banknotes contamination, was studied to determine the option of UV varnishing, which will be the most optimal to improve the resistance of banknotes against to contamination. Also, the innovative technological processes of banknote surface antibacterial protection are proposed, in a particular banknote surface coating with varnishes that include silver nanoparticles, which have great bactericidal action. Methods of synthesis and stabilization of silver nanoparticles in aqueous solutions and organic solvents used for the inclusion into water-soluble and UV varnishes are considered. Conditions for the inclusion of silver nanoparticles in water-soluble and UV varnish have been established. The morphology and spectral characteristics of the obtained silver nanoparticles were studied. The methodology of decolorization of aqueous solutions of silver nanoparticles was developed in the paper, it was proposed to use such polymers as polyvinylpyrrolidone and sodium polyphosphate to increase the stability of nanoparticles. The influence of varnish compositions - water-soluble and UV varnishes - on the stability and spectral characteristics of silver nanoparticles has been studied.
The microgeometry of the paper surface in the watermark area and beyond was investigated using an optical non-contact contactless profilometer. This made it possible to obtain quantitative characteristics of the surface roughness of the studied paper samples, to measure the height and depth of relief, to obtain the distribution of projections by area, as well as to construct a 2-D and 3-D images of the surface, to observe the interference images of the paper surface in white and in monochromatic light. It has been found that the structural parameters of the surface of the protected paper are not the same for areas with and without watermarks. The results of the interference-based measurement make it possible to determine promptly the roughness indices that are subsequently used to determine the surface quality of the paper and to calculate the strength of the ink layer in areas of paper without watermark and with a negative watermark. The constructed 3-D profiles of the paper surface clearly demonstrate the size and number of randomly arranged fibers and filler particles in the paper pulp in the watermark area and beyond, on a given scan path.
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