Resumen
An experimentally determined list of the required and sufficient technological operations to produce semi-hard book covers has been proposed, with the calculated contour and structural design, which implies strict tolerances in the deviations from a rectangular planar geometry.It has been proven that the main features in the modeling and manufacturing of covers affect the conditions for ensuring tolerances, as well as stable circulation quantity. They imply that the edges and flaps as the additional structural elements of the covers form, after folding and gluing to the main part, a double composite structure.Due to this, there are no laps in the joints of edges and flaps, so the plane of the inner part of the covers acquires a flat shape, without defective contours. Therefore, one can argue that the parallel deviation of the outer contours of semi-hard covers from a rectangular design will not exceed the ranges for bookbinding divided into groups based on quality indicators.It should be particularly noted that the conditions for providing tolerances, circularity stability, as well as the composite structure of semi-hard covers, are influenced by the roller-roll mechanisms, which perform their rotary pressing and high-speed coordinated transportation during manufacturing.The current study into the effect exerted by the plastic deformation has established the mechanisms of the process of improving a cylindrical surface of the rotary-pressing rollers. It has been proven that they imply the formation of a completely regular microrelief of the hexagonal type with a concave shape and a partly regular micro-relief, in the form of the flat-parallel slotted recesses arranged at an angle to the central axis of the rollers. As well as the application of technology of the ionic nitriding of the obtained microrelief in the plasma of the helicon discharge.The final stage of strengthening a near-surface layer of the rollers with ionic nitriding in the plasma of the helicon discharge captures the maximum level of the increased durability of the near-surface layer. It fluctuates in the range of the ratio of the plane onto which a regular microrelief is partially applied to the general plane of the roller?s surface