Characteristic Analysis And Optimization Of Multifunctional Compound Machine Tool

As the working master machine of equipment manufacturing industry,multi-functional composite machine tool is widely used in the related fields of processing and manufacturing because of its unique advantages of one-time clamping to complete turning,milling,rolling and other processes,and plays an indispensable role in modern manufacturing industry.With the development trend of high-speed,high-precision and high stability of multi working condition compound machining technology,the performance requirements of the machine tool are higher and higher.Therefore,it is of great significance to improve the static and dynamic characteristics of machine tools to improve the rigidity and vibration resistance of machine tools.This paper mainly focuses on the related problems of the structural optimization design of machine tools.Taking the key components of the self-developed multifunctional composite machine tool as the research object,aiming at the problem of the poor static and dynamic performance of the machine tool,using the means of theoretical model creation,finite element analysis,structural optimization design and so on,this paper puts forward a new method of sensitivity analysis,Latin hypercube experimental design,EI The multi-objective optimization of machine tool structure is studied by using Kriging model,NSGA-?genetic algorithm and weight coefficient screening.The main contents of this paper include:(1)Firstly,based on the solid model of the machine tool established in SolidWorks,combined with statics and finite element analysis theory,the finite element model of the whole machine tool is established in workbench.After the limit machining position of the machine tool is determined,the load effect of different machining methods is analyzed and calculated in turn.The static characteristics of the machine tool under turning,milling and hobbing conditions are analyzed,and the deformation and stress of the machine tool are obtained Cloud chart,comparative analysis of displacement,stress and static stiffness under different working conditions,and finally make sure that the milling of machine tool is the limit working condition,and identify the machine tool column structure as the weak link of static characteristics of the whole machine.(3)Then,on the premise of fully considering the necessity of the machine tool joint,two kinds of main joint parts are included in the machine tool in detail: the bolt fixed joint part and the sliding guide joint part.Based on th e virtual medium method,the parameters of the joint part are identified to improve the accuracy of the analysis of the whole machine tool's characteristics.Then,according to the theory of modal analysis and harmonic response analysis,the machine tool w ith the joint part characteristics is analyzed Dynamic characteristic analysis,the natural frequency and main vibration mode of the machine tool are obtained through modal analysis,and the harmonic response curve of the machine tool is obtained through h armonic response analysis.Combined with the consistency of static and dynamic characteristic analysis results,the column is determined as the key structural part affecting the performance of the machine tool.(3)Finally,according to the static and dynamic weak link column structure of the machine tool,the response surface model is built based on the sensitivity analysis,the Latin hypercube experiment design,the variable space range and the dynamic adding point criterion model,and the multi-objective optimization design is carried out with the target of low-cost natural frequency,stiffness and quality of the machine tool.The pare is obtained by using the non dominated sequencing genetic algorithm Finally,according to the actual requirements,the optimization data that meet the conditions are obtained by the weight coefficient method.The results show that the first and second natural frequencies of the machine tool are increased by 10.21% and 6.25% respectively after optimization,and the maximum resonance peaks in X,y and Z directions are decreased by 39.1%,37.7% and 23.5% respectively.The static and dynamic performance of the machine tool is significantly improved after optimization.