Fault Risk Assessment Of CNC Lathe Components Based On Grey Clustering

The CNC lathe is a dynamic complex system contains multiple components,and once each component is failure,which will leads to machine failure because of fault related.Therefore,considering the fault correlation between components,it is of great significance to make the risk assessment of CNC lathe components in order to make the maintenance plan of lathe components.In this paper,the fault probability of the lathe and its components is modeled based on the data of 22 CNC lathes.A symbolic directed graph is used to describe the relationship between faults in CNC lathe components.Pagerank algorithm is used to calculate the fault influence degree and the influenced degree of each component of the lathe.Finally,failure risk is evaluated by the grey clustering method.The influence degree,and the influenced degree,the occurrence degree and the severity degree are taken as the evaluation index of the fault riskFirstly,fault probability modeling of NC lathe and its components is established.According to the composition and processing principle of NC lathe,the lathe components are divided.For the collected data,the Minitab software is used to identify the reliability distribution.Due to the existence of censored data,the average rank method is used to modify the order.Thus,the failure probability model of the CNC lathe and the fault independent component is obtained.Secondly,Fault association model based on signed directed graph.The fault association between NC lathe components is described by signed directed graphs.The Pagerank algorithm is used to calculate the influence degree and the degree of influenced of the CNC lathe components.Finally,considering the component fault correlation,the influence degree and influenced degree of fault,component failure probability,average repair time to construct hazard risk index evaluation system of NC lathe.Grey clustering method is used to evaluate the risk of CNC lathe components...