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 article presents the results of foil embossing studies on synthetic paper. Based on the results of research, the influence of technological modes of foil embossing on the optical indicators of prints has been determined. According to the obtained results, the following regularities were found: at the heating temperature of the cliché in the range of 60-80 ºС, the transfer of the foil occurs unevenly, with indistinct torn contours, which is also characteristic of materials based on cellulose fibers; optimal reproduction of the image was obtained at temperatures of 95-120 ºС, embossing time 1 s; when the heating temperature increases above 130 ºС, the image is distorted, the material is significantly deformed, the color of the foil significantly changes, and the gloss changes, which primarily affects paper with a thickness of 200-300 microns.
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.
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