Design And Optimization Of Ball Screw Feed Double Drive System Of CNC Machine Tool

With the development of CNC machine to high speed,high accuracy and high stability,the traditional feed method of single ball screw is prone to vibration in high speed feed for large moving parts.Because single ball screw is difficult to reach the center of gravity.So the application of double drive screw feed system has been more and more in recent years.Double drive feed system has one more set of feed parts,which makes the design and modeling analysis more complicated.In this paper,the design and optimization of double drive ball screw feed system of CNC machine tools are studied.On the basis of summing up the advantages and disadvantages of double drive and the differences from single drive in design,this paper puts forward the design method of double drive ball screw feed system.This paper builds the model of the double feed system's position error and the angle error considering redundant constraints,the main components and the main error sources.Considering the length of moving parts and the position of load,this paper studies the distance of ball screws and the distance of guides.The optimal coefficient of the combination of distances for single target and optimal combination of distances for multiple target are obtained.The design and optimization software for double drive ball screw feed system of CNC machine is developed.In the first chapter,the related research about the design of feed system of CNC machine is summarized.The existing problems of these technologies for dual ball screw feed systems are discussed,and the structure of the article is introduced.In the second chapter,the principle of double drive,is introduced.On the basis of summing up the advantages and disadvantages of double drive and differences from single drive in design,this paper puts forward the design method of double drive ball screw feed system.In the third chapter,Clearance error is divided from the error source.This dissertation puts forward the concept of error region and studies the graphical and mathematical expressions of error region.And the influence of clearance error and multiple redundant constraints on the mechanism is analyzed.This paper builds the model of the double feed system's position error and the angle error considering redundant constraints,the main components and the main error sources.In the fourth chapter,considering the length of moving parts and the position of load,this paper analyzes a large number of combination of the distance of ball screw and the distance of guide.The optimization objectives include error,static deformation and natural frequency.The change trend of single target,optimal interval of the combination and the optimal coefficient of the combination are obtained.Then,the problem of the distances combination for multiple target is solved by means of Kriging method and NSGA-?algorithm.In the fifth chapter,the frame of the design and optimization software for double drive ball screw feed system is introduced.Then,the author introduces the functional module of the software.At last,the software is validated by the design of the Z axis feed system of turning and milling machining tool which named VTM200/F5.In the sixth chapter,the further research is put forward after summarizing all the achievements of this dissertation.