Reserch On Optimization Design For Worktable Base Of 2V19 Heavy-duty Vertical Lathe

Heavy-duty vertical lathes are used to machining parts in large dimension the diameter,generally larger than 4m in diameter.Static and dynamic performances of heavy-duty vertical lathes play an important role in affecting the machining accuracy which directly determine the quality of parts being machined.The worktable base is one of the core components of vertical lathe the performances,such as static stiffness and dynamic characteristic,of which should be guaranteed to achieve the desired machining accuracy.To cater the design requirements of these two aspects,structural design methods based on lightweight idea have become one of the spots in the research area of structural optimization.However,the presently traditional structural design methods for machine tool components,such as experiential method and engineering analogy method,are far from perfect to meet the high-precision and lightweight needs for the development of heavy duty machine tools.There is important engineering value and research significance to study the optimized design of the base structure of the heavy-duty vertical lathe workbench.Due to the large size and complex structure of heavy-duty machine tools,the influence of its dynamic characteristics on processing performance needs further research and verification.Therefore,the geometric model of the workbench is first established based on the principle of engineering simplification,and the stress of the workbench base under typical working conditions is analyzed.The finite element model of the workbench base is established using the tetrahedral meshing technique,and the finite element simulation was used to analyze the dynamic performance of the structure using the modal analysis and the harmonic response analysis technique to identify weak parts in the workbench base.The multi-reference hammering technique was used to perform modal tests on the workbench base.The finite element model and simulation results was verified by comparing the modal simulation and modal test results.The speed sensor is used to collect the vibration data of the workbench in the cutting state and the no-load state,and the weak part of the workbench base is determined by the time-frequency spectrum analysis,so as to provide guidance for the determination of the design area when the subsequent workbench structure is optimized.Topology optimization and size optimization techniques are used to optimize the structure of the vertical lathe worktable base.Firstly,a topological optimization model of the workbench base structure was established.Based on the variable density method,the conceptual model of the workbench was obtained with the structural flexibility,natural frequency and the weighted sum of the two as the optimization objectives.Then a detailed design model of the base structure is established based on the topology optimization analysis results.The response surface method is used to establish the optimization model of the number of ribs and the size parameters,and the final optimization scheme of the workbench base is redesigned.In order verify the structure optimization method of the workbench base proposed in this paper,the simulation and experiment results are compared and analyzed.Modal analysis shows that the improved first-order natural frequency of the structure is increased by 16.82%.The harmonic response analysis shows that the resonance frequency in three directions is increased by more than 20%,and the weak part of the base is improved.The modal test showed that the first-order natural frequency increased by 18.4%,and finally verified that the optimization result meets the requirements of the dynamic performance index,providing a reference for the design of the workbench base.