Optimal Design And Performance Analysis Of Bed Structure Of Composite Boring And Milling Machining Center Based On Gray Theory

As an important part of the CNC center,the main function of the machine bed is to connect the column,table and other structures and bear the structural gravity of each component,and the reliability of the structure and its own quality have a great impact on the overall performance of the machine tool.In the process of machine tool bed structure design,the traditional empirical design does not consider the influence of randomness of structural design parameters on the structure.Taking the composite boring and milling machining center TX1600 G as the research object,this paper uses the optimization design method combining gray system theory and multi-objective topology optimization to optimize the structure of the machining center bed,and the research content includes the following points:(1)Analyze the machine tool structure and bed structure characteristics of composite boring and milling machining center.Calculation of cutting forces for milling and boring systems in composite boring and milling centers.(2)Draw a three-dimensional model of the machine bed and analyze its dynamic and static characteristics.In order to determine the maximum dangerous working conditions of the bed,simulate different milling processing conditions,and select 5 positions at the beam and the bed guide rail to carry out a set of orthogonal tests.25 processing conditions were simulated,and the dynamic and static characteristics of 25 working conditions were analyzed to obtain stress,displacement clouds and the first five-order frequency clouds of the bed.Through the orthogonal test results,the working condition with the largest total displacement is obtained,and the stress concentration of the bed and the maximum area of displacement deformation are clarified.(3)The "well" shape structure under the bed guide rail was simplified and filled,the multi-objective topology optimization of the bed structure was carried out,and four new bed structures,four groups of stiffener plate positions and four groups of rib plate thickness were designed according to the topology optimization density cloud and static analysis displacement cloud map.(4)Design 16 groups of bed structure optimization schemes,take the bed configuration,rib plate position and rib plate thickness as design factors,and take the dynamic and static characteristics and quality of the machine tool bed as a reference,and carry out a set of orthogonal tests of three factors and four variables.The correlation degree between the parameters of the 16 groups of design schemes was calculated by using the gray correlation analysis method,so as to determine the optimal combination of each design factor and obtain the optimal parameter combination of the bed structure.According to the gray correlation analysis,a new bed structure is designed,and the dynamic and static characteristics are analyzed,and the results show that compared with the original bed,the total displacement is reduced by 15.6%,and the first-order natural frequency is increased by 7.94%.Under the condition that the overall weight gain is very small,the dynamic and static characteristics of the machine bed in the composite boring and milling process have been improved to a certain extent to meet the design requirements.