The mechanical strength of unreinforced abrasive wheels is determined by centrifugal and bending forces, but their distribution during reinforcement is unknown. It was assumed that the stresses are distributed evenly, but a comparison of calculations on the theory of elasticity and real characteristics on a special stand showed complete discrepancy. Tensile tests of the wheels made it possible to compare the stresses results in the circumferential and radial directions. Was found that the reinforced wheel is an anisotropic body. Anisotropy can be reduced by displacing one reinforcement mesh relatively to the other by angle of 45°. In this paper, a mathematical model of the stress-strain state of the abrasive reinforced wheel was developed, taking into account the anisotropy of its properties. To determine the centrifugal forces, the theory of elasticity for an orthotropic body is applied. The bending forces that arise in the working wheel were determined during solving the problem of the distribution of deformations in the anisotropic annular plate rigidly fixed along the inner contour. As a result of experimental studies, it was found that stresses reach 8...23 MPa, which can be compared with the ultimate strength of the wheel matrix. The elastic module of the wheel matrix is noticeably greater than the elastic module of the reinforcing mesh, which practically does not perceive the load at the initial stage. The developed mathematical model of the strength indicators for abrasive reinforced wheels makes it possible to predict their reliability and safe operation.
Formulation of the problem In modern sheet-cutting machines the trimming method is applied. That is the machine process when the knife cuts a pile of sheets and cuts into the counter-knife at the end of the kinematic cycle. Each cycle of knife motion is accompanied by complex technological processes. Under the effect of significant loading acting on the knife and, especially its hitting at the end of kinematic cycle, an accelerated dulling of its cutting edge appears. This leads to deterioration in the cutting quality and consequently to appearance of the finished product rejects [1]. The method without using counter-knife excludes its applying. This means that knife does not contact the bearing surface of the counter-knife in the process of trimming, but only the sheet material. This increases greatly the durability of the cutting tool its operation [2, 3]. Analysis of previous studies Devices for sheet materials cutting include a leveling system and toothed passing conveyors. The transportation system can consist of a tool unit with fixed cutting tools [4-6]. The sheet material is driven to the cutting area at constant speed V A along the transfer table towards the tooling unit. Due to the same direction of drums rotation as well as to interaction between the cutting tool and the counter-knife, it is possible to cut a defined area of the material. Under condition of the step of the cutting tool being equal and V A = ω. r = const the sheet can be trimmed along a defined line. To provide the shape of the cut, the sheet can move at variable speed V A. Purpose of the work The purpose of this work is to analytically determine the potentiality of applying a new method without using counter-knife for sheet material during its trans-UDC 686.12.056 © A. І. Іvanko, Candidate of Engineering sciences (PhD), Associate professor, O. S. Marchenko, graduate student, Igor Sikorsky Kyiv Polytechnic Institute, Kyiv, Ukraine METHOD OF SHEET MATERIAL TRIMMING WITHOUT USING COUNTER-KNIFE The purpose of this work is to analytically determine the possibility of a new method without using counter-knife of sheet material during its transportation in a rotary cutting section. Consider the pneumatic module counter-knife.
ОБРІЗУВАННЯ АРКУШЕВИХ МАТЕРІАЛІВ У ПНЕВМАТИЧНИХ ТРАНСПОРТУВАЛЬНИХ СИСТЕМАХ У статті розглянуто пневматичну систему для транспортування аркушевого матеріалу у зону його обрізування. Ключові слова: аркушевий матеріал; вакуумна камера; транспортувальна система; обрізування; дисковий ніж; самонаклад; приймальний стіл.
Київський національний університет будівництва і архітектури (КНУБА)Повітрофлотський просп. 31, Київ, Україна, 03680,
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