Research And Analysis Of Static And Dynamic Characteristics Of Vertical CNC Milling Machine And Its Key Components

As a high-end processing equipment,CNC machine tool plays an irreplaceable role in the development of manufacturing industry,so people pay more and more attention to the research of CNC machine tool.Compared with foreign CNC machine tools,domestic CNC machine tools still have a certain gap in machining accuracy,stability and reliability.How to improve the overall performance of CNC machine tools and achieve high quality and high efficiency processing tasks has become an urgent problem for researchers in domestic universities and enterprises.This paper takes a vertical CNC milling machine and its key components as the research object.Based on the finite element method,the static and dynamic characteristics of the milling machine structure were studied and analyzed.On this basis,the structure of the beam and column of the CNC milling machine were optimized respectively.The research work of this paper is as follows:(1)The parametric model of two key components of CNC milling machine beam and column was established.According to the actual load of the two components in the milling machine,the mathematical model of the component structure was established and solved.The structure of the two parts model was simplified appropriately,and the corresponding finite element model was established.(2)This paper analyzes the static and dynamic characteristics of CNC milling machine,understands the performance of the whole machine,and determines that the crossbeam is the most critical and weak part in the milling machine structure,which provides a reference for identifying the weak parts of the milling machine structure.(3)The static analysis and modal analysis of beam and column were carried out,and the stress,strain and deformation of beam and column structure were determined under the most dangerous working condition.Then,the first six natural frequencies of beam and column were obtained through modal analysis,and the vibration of components under each natural frequency was obtained.Finally,the steady-state response of the structure under periodic load was obtained by harmonic response analysis.Through the above analysis,it is determined that the total deformation and the first-order natural frequency of the beam are the objectives of optimization.Besides,the design of the column is too conservative,resulting in its mass is too large.Therefore,it is necessary to carry out the weight reduction design.(4)Based on the optimization design theory,the beam and column were optimized.According to the static and dynamic analysis results of the beam,a multi-objective optimization design method based on sensitivity analysis and box Behnken test design was proposed.After optimization,the static and dynamic characteristics of the beam were improved to varying degrees.Aiming at the problems of conservative column design and heavy weight,the lightweight design of the column was carried out to reduce the weight of the column,and then the size optimization was carried out to improve the performance of the column.