On the design of a wood rolling machine

Abstract

One of the types of technologies for using soft-leaved wood can be rolling in rolls. At the same time, waste is reduced, it is possible to obtain high physical and mechanical properties of wood. The installation can be relatively simple, have a low material and energy consumption. The method of rolling wood in rolls is little studied. The application of the theory of metal rolling is difficult. These theories are based on the representation of the material as isotropic and plastic. When designing the installation, an assessment of the self-tightening condition was given. When the size is reduced from 100 mm to 70 mm with a coefficient of friction less than 0.2, it leads to a significant increase (up to 3000 mm) in the diameter of the rolls. In order to reduce the overall dimensions of the installation, a scheme with freely rotating rolls with preloading of the workpiece with some axial force was adopted. The expressions obtained to determine the total and axial forces showed that, depending on the degree of compaction, the resulting forces reach significant values. This circumstance served as the basis for the design of a multicellular rolling plant. In general, when designing a multicellular installation, there are a number of somewhat independent parameters: the rolling speed, the distance between the stands, the clearance between the rolls, the diameters of the rolls. Among the efficiency indicators can be distinguished: axial (tangential) and normal forces, power consumption, degree of compaction and corresponding physical and mechanical properties of wood, surface quality and parameters characterizing the shape of the product. For the optimal design problem, the dependence of the tangential force on the degree of compaction can be taken as an objective function. With the assumptions made, the objective function and constraints are linear and the task of finding optimal values of the degree of compaction by steps can be done using linear programming methods. The developed technique makes it possible to determine the normal and tangential forces, as well as the required drive power of the installation, depending on the required degree of compaction of wood. A method of optimal design of a multicellular installation has been developed, which provides a rational distribution of degrees of compaction by stages with minimal preload force.