Optimization Of Large-scale Floor Boring Milling Machine About Workbench Structure And Dynamic Characteristics

The development of the heavy-duty machining center industry is the basis for the implementation of the China Manufacturing 2025 strategy.The production of large-scale equipment in the intelligent process has increased the machining accuracy of the machining center,which requires the stability of each functional component to be improved.The basic components of the boring and milling machine worktables produced in mass production at home and abroad are almost the same,but the load capacity of the domestic boring and milling machine tables is not strong,the processing quality is not high,and the processing performance is not stable,and it is difficult to apply to heavy-duty machining centers.In this paper,through the combination of theoretical analysis and experiment,the static characteristics of the boring and milling machine worktable,the deformation in the process of machining parts,and the processing vibration characteristics are studied to improve the machining performance of the boring and milling machine worktable.(1)Analyzing the working performance of the hydrostatic guide rails of the boring and milling machine table is combined with the technical specifications and bearing requirements of the TH6920 boring and milling machine table to complete the selection of the hydrostatic guide rails.The constant pressure closed hydrostatic linear guides and circular guides were designed,and the analysis of the changes of the main and auxiliary oil chamber pressures and the oil film thickness with the eccentric load distance under the eccentric load condition was analyzed.Machining the position of the workpiece lays the foundation for the modal analysis of the boring and milling machine table.(2)The finite element software was used to analyze the overall deformation,stress and strain of the boring and milling machine table correction model under the actual working conditions.A laser tracker was used to measure the deformation of each position of the workbench,and the working condition of the workpiece with a partial load distance of 750 mm from the center axis was studied.The maximum deformation of the work table under this condition was 7 ?m,and the maximum stress was 4.786 Mpa.This verifies the accuracy of the static analysis results.The asymmetry of the load axis is the main factor that affects the deformation of the table.(3)Through the finite element modal analysis,study the vibration of the boring and milling machine table correction model when the workpiece is subjected to cutting load,and the natural frequency of the table can be obtained from the analysis results.Orthogonal experiment was used to design the cutting parameters and the vibration experiment was carried out.The corresponding frequency response function was obtained.The calculated experimental results were compared with the simulation results.The maximum error of the two natural frequencies was only 6.65%,which verified the modal analysis results.Accuracy.The analysis and comparison results prepared for the optimization of the boring and milling machine worktable structure.(4)By analyzing the ribbed plate structure type of the boring and milling machine,the square sand hole parameters are taken as the optimal design variables.According to the dynamic optimization design principle of the meta-structure,the optimal structure type of the boring and milling machine workbench and the best sand-blasting hole parameters are obtained.The results before and after the optimization are compared,the natural frequency of the modified structure is increased,the deformation is reduced,and the stiffness performance is improved.