Rapid Reliability Test And Evaluation Of Cnc Feed System

As the core component of the CNC for precise movement,the performance of the servo feed system has a decisive influence on the machining accuracy and production efficiency of CNC.Once a failure occurs,it will have a serious impact on the mass production cycle,so its reliability level is required extremely high.Reliability test technology is an important means to evaluate and improve the reliability level of the feed system.Traditional reliability test technology requires long-term reliability data collection and analysis of equipment.The reliability evaluation cycle is very long,which is not conducive to the development of new products of CNC machining centers.Therefore,this paper develops the theoretical and experimental research on the rapid reliability assessment method for the feed system of the machining center of the car power assembly production line to realize the rapid assessment of the reliability of the feed system,which has important theoretical and practical significance.The main research contents and results are as follows:(1)Failure mode and degradation failure analysis of feed system.The Failure Mode and Effects Analysis(FEMA)of the CNC servo feed system for the car power assembly production line was carried out,and the failure mode and cause of the feed system were analyzed.On this basis,the degradation failure mechanism of the feed system is analyzed,and the parameters of performance degradation is selected.(2)Test principle and test design of feed system acceleration performance degradation test.The basic principle of the acceleration performance degradation test of the feed system was researched.Based on the feed drive current signal of the CNC on the production line,the load spectrum data of the feed system during processing was collected,and the load of the servo feed system was determined while normal processing,and the current statistics of each servo axis are used to characterize the load level.The reliability of the servo feed system was statistically analyzed based on the production line operation data.Based on the principle of cumulative damage,the design of the accelerated performance degradation test of the feed system was completed,including test flow design,test loading scheme design,test task profile design,and test data acquisition design.(3)Rapid reliability evaluation method and test research of feed system.A reliability evaluation method based on performance degradation data under accelerated loading levels is proposed.Based on accelerated test data,the performance degradation model of servo feed system performance data was modeled using a one-variable Wiener process and the pseudo-failure life time under different accelerated loading levels was calculated;based on the anti-power law model,the pseudo-failure life time under normal processing loading level was derived;Based on the Weibull distribution,the reliability level evaluation of the servo feed system was completed.Finally,the evaluation results are analyzed and verified by experiments.