Reliability Analysis Of Heavy-duty CNC Boring And Milling Machine Based On Universal Generating Function

As an important basic equipment in the manufacturing industry,heavy-duty CNC machine tools provide equipment guarantee and technical support for the fields related to national security and people's livelihood such as national defense,military industry,and aerospace.The level of processing and manufacturing directly affects the progress of the manufacturing industry.Although the technical level of CNC machine tools in our country has been significantly improved,compared with mature foreign machine tools,there are still many reliability problems,such as frequent failures,difficulty in tracking the causes of failures,and low machining accuracy.Therefore,it is of great significance to the reliability research of heavy-duty CNC machine tools.Due to the lack of historical data,the inability to carry out a large number of reliability tests on the machine tool,insufficient reliability information collected,and changes in the working environment of the machine tool,there is a large amount of uncertainty in the machine tool,and the subsystems show signs of performance during operation.Multiple performance states.This article will study the uncertainty and polymorphism in machine tools.The details are as follows:(1)Based on the analysis of the working principle and functional structure of the whole machine,the division of subsystems lays the foundation for the subsequent reliability analysis of the machine tool.Through the analysis of maintenance data,the main failure modes and common failure subsystems of the machine tool are found,which are the main research objects of this article.(2)Reliability analysis of milling shaft structure based on universal generating function.Through failure analysis,mechanical component failure is the main failure mode of heavy-duty CNC milling and boring machines,and milling shaft failure is the main failure of mechanical components.Through the analysis of the milling shafts of heavy-duty CNC machine tools,various uncertain factors and quantification methods that affect the reliability of the milling shafts,a structural reliability analysis model of the milling shafts based on the universal generating function is constructed.(3)Sensitivity analysis of fatigue strength of milling shafts of heavy CNC machine tools According to the fatigue strength model of the milling shaft,local sensitivity analysis and global sensitivity analysis are carried out on the basic variables that affect the fatigue strength of the milling shaft,and the factors that affect the fatigue strength of the milling shaft are obtained.(4)Reliability analysis of feed control system for heavy-duty CNC machine tools.In view of the frequent failure of the machine tool subsystem,the reliability analysis of the multi-state system is carried out,the Markov model is used to establish the state degradation process of the component,and the uncertainty of the component degradation parameter is quantified by evidence theory,using conditional trust However,the table calculates the reliability of the system.The evidence theory is introduced into the traditional Birnbaum importance analysis method.When considering the uncertainty of the component degradation parameters,the component importance is analyzed to obtain the component importance interval,and the component importance is sorted to identify the weak links of the entire system.