The 3D Tolerance Analysis And Optimization Research Of Numerical Control Machine Turntable

In the global competitive situation,the speed of the product update is accelerating,and the computer aided technology(CAD/CAE)has developed quite mature.Through the use of these software,it has made considerable progress in the mechanical design and analysis.However,3D tolerance design is still in a relatively backward stage.The traditional tolerance allocation only depends on the experience design,which leads to the long design cycle and the increase of design cost.Therefore,computer aided tolerance technology has become the key to solve the problem.This topic is from a Kunming machine tool factory major scientific and technological assistance project:the research object is the horizontal NC machine tool turntable,turntable is an important part of the machine tool and mainly used to support the workpiece to have Forward and backward movement and Circular motion.The turntable is the key part of the machine tool,which has the characteristics of complex structure and various components.The precision of the part directly affects the machining accuracy.In the process of testing the turntable of the machine tool,it is found that there are some uncertain factors that lead to the phenomenon of shaking during the rotation of the turntable in the same batch.In view of the problems,R&D personnel conducted a series of investigation,excluding motor output power instability,product quality,control systems and installation and so on turntable may cause the phenomenon.According to the user's feedback,the strength,stiffness and performance of the turntable have met the requirements of the customer,but the stability of the turntable needs to be further improved.It is considered that there may be some problems in the initial design of the tolerance of the turntable parts.So it is necessary to analyze the design tolerance.The research contents of this paper are as follows:(1)Learning the relevant theoretical knowledge about tolerance analysis,comparing the advantages and disadvantages of traditional tolerance analysis and three-dimensional tolerance analysis and making three-dimensional tolerance as analysis software.(2)Learning the theory of tolerance representation of 3D tolerance analysis,the theory of vector ring modeling and the theory of tolerance analysis.(3)According to the theory of tolerance analysis combined with the turntable practical problems,tolerance model and analysis using 3D tolerance software,get the assembly dimension analysis and contribution,the results of the sensitivity analysis,for the next work to provide theoretical support and tolerance optimization direction.(4)Basing on the tolerance optimization theory,combined with the results of the three dimensional tolerance analysis,the optimization platform OPTIMUS is used to optimize the tolerance and the tolerance analysis results are compared.(5)Considering the impact of external forces on the turntable assembly under actual working conditions,using the finite element analysis of force deformation influence on the assembly and the effect of gravity on the assembly,the tolerance analysis has more practical significance.In this paper,combined with the practical problems of the NC machine tool turntable,the three-dimensional tolerance analysis and optimization theory are used to evaluate and optimize the assembly of the turntable.The results show that the assembly accuracy and assembly quality of the turntable are greatly improved compared with that before optimization.At the same time,this study also provides a reference for other similar products.