Improving the technical characteristics of machining center at the design stage
Introduction. The development of optimal technical characteristics of machine-tools at the design stage is a long-range objective of the machine-tool industry. To solve this problem, a technology for designing basic details of heavy machining center with using of the finite element method and optimization methods are proposed. The design procedure includes: 1) calculation of the system carriers with basic details of simple geometry (rod, plate, shell), 2) calculation of the base part to determine the required geometry of its cross section, 3) dynamic analysis of the machine-tool as a whole. The purpose of this work is to present the main results of the design of the system carriers of the heavy machining center of a drilling, milling and boring group. Results and discussion. At the design stage of the system carriers, the adequate overall dimensions of the base parts and the boundary conditions (force and deformation) in the areas of its contact are determined. At the second stage, a separate basic part of the actual layout is explored using the column as an example with the selection of a small fragment in the contact zone of the column and the spindle head. It is shown that the calculated field of displacements of the nodes of the column fragment is adequate to the field of displacements of the corresponding nodes of the column, obtained by calculating it as part of the system carriers. As a result of the optimization, the torsional stiffness of the column is increased by 48%. To study the dynamics of the machine, a dynamic model is built and comparative calculations with forced oscillations of the machine is carried out. For a machine with optimal base parts, there is a reduction in compliance by 30% in the direction of the greatest component of the cutting force and a decrease in mass by 17% in comparison with the serial version.