Evaluation Of Residual Stress And Optimization Of Thermal Aging In The Manufacturing Process Of Key Parts Of Horizontal Machining Center Based On Finite Element Analysis

The residual stress level of the key parts of CNC machine tools affects the accuracy retention of the machine tools.At present,most researches on residual stresses of machine tools only focus on the numerical values of residual stresses on key parts,and only research and analyze the effect of eliminating residual stresses.There is a lack of evaluation methods for residual stress levels of key parts on CNC machine tools,and the relevant parameters of the enterprise's thermal aging process come from empirical cognition.It was found through research that creep deformation during machine tool service process was caused solely by residual stress,and the creep deformation of the key parts of the machine tool has an important influence on the machining accuracy of the machine tool;and finite element can effectively simulate the thermal aging process.Based on this,this article analyzed the change and distribution of residual stresses in the manufacturing process of horizontal and heavy parts.,and carried out simulation and experimental research on residual stress of many types of parts;Whether the component meets the design accuracy requirements under the action of residual stress;the thermal aging process was optimized.This has a high theoretical and engineering significance for enterprises to adjust critical key parts to optimize thermal aging process parameters and improve the low stress manufacturing process structure of critical key parts.The main research contents of the paper were:(1)A multi-process continuous finite element simulation platform for residual stresses of key parts was built.Analyzed the processes involved in multi-process continuous finite element simulation of residual stresses in key parts,And selected the function-matching finite element analysis software accordingly;Analyzed the functions of the software to ensure that the data between different software and different processes can interact completely and smoothly;Configured appropriate hardware facilities to carry software to ensure the normal operation of the software,and established a technical route for continuous finite element simulation of multiple processes for heavy parts,and build a complete simulation platform.Finally,the theoretical basis of the finite element involved in the finite element analysis was studied.The simulation platform with complete functions and complete data and a complete theoretical foundation provided the prerequisite basis for subsequent research.(2)Established a continuous finite element model of residual stress in the manufacturing process of key parts and supplement it with experimental verification.The finite element model of the residual stress in the manufacturing process of the bed,column and spindle box from casting to finishing was carried out.Analyzed the cumulative change law of residual stress in multiple steps of the manufacturing process of the critical parts.Then,through the blind hole method,all the simulated production links of the three critical parts were tracked and tested for residual stress.And experimental results verify the effectiveness of continuous finite element simulation.(3)Based on the creep finite element model of the bed,column and spindle box of the horizontal machining center,the residual stress levels and stress relief effects of the three weights were evaluated.The creep constitutive model of the bed,column and spindle box is determined according to the material characteristics of the parts;With the help of finite element software,the creep deformation values of the three key parts of the machine tool were calculated after 3 years.Analyzed the changing law of the maximum displacement of each key part with time;Then used the creep displacement of the center line of each rail mounting surface of the key parts to replace the displacement of the rail mounting surface.According to the design accuracy requirements of the critical parts,evaluate whether the creeping parts after the creep meet the design accuracy requirements.(4)Optimized the thermal aging process of key parts based on finite element simulation,and used creep simulation to modify the optimized parameters.Based on the results of comparative experiments and simulations,the optimization of the thermal aging process sequence of the machine tool's heavy parts;Explored the optimization scheme of thermal aging process for key parts of machine tool,and established the finite element simulation model of key parts under different heating and cooling speeds.Based on the law of residual stress changes,the heating and cooling rates were optimized and selected,and the creep simulation results were used to evaluate the stress field of the bed,column,and headstock under new heating and cooling rates,and the inappropriate parameters are corrected and improved.Finally,based on the comprehensive evaluation results of residual stress and creep displacement,more appropriate thermal aging process parameters were optimized.