Reliability Analysis And Evaluation Of Five-axis Gantry Machining Center

Improving the reliability of the domestic CNC machine and its key functional components is the primary task which complied with the development tendency of high precision,high efficiency,high speed,flexible and complex processing.As the key component of the reliability engineering technology of CNC machine,the reliability evaluation technology is the key point to find out the design defects of the machine tools,to verify the reliability indexes of the machine tools and to develop the maintenance strategy of the machine tools.This dissertation was carried out under the support of Jiangsu Science and Technology Support Project—"Research on Green Design Technology and Application of Large High-speed Precision Five-axis Gantry Machining Center".In course of this research,the reliability technology system is used synthetically to evaluate the reliability of the Five-axis Gantry Machining Center.The main contents of this paper are as follows:1?In the stage of product design,the failure positions,failure modes and failure causes are analyzed with FMEA method based on the failure data,which collected from similar products.Then the weak positions are found and the corresponding improvement measures are put forward,which are helpful to improve the reliability of design stage.2?The failure model is established by using the distribution fitting test method based on the failure interval data which gathered from the similar products.The obtained Weibull model is used to analyze the distribution of reliability.Through the study of the reliability of the different failure time distribution,a modeling method based on every sequence fault time is present,which can assess the reliability level of various sequence fault time.3?In the prototype stage,considering actual conditions of machining center,the orthogonal test is designed to obtained the relatively comprehensive load spectrum during cutting process.In order to obtain the tendency of failure rate,the WPHM is established using the mean value of load spectrum as a single covariate.Besides,the load spectrum of ball screw is obtained by establishing dynamic simulation model,which is useful to analyze the static strength reliability and fatigue life of the ball screw.4?Gray GM(1,1)prediction model is established based on fault sequence to realize prediction for failure time,which can provide theoretical basis for the maintenance personnel to find the potential failure and maintain timely.In this way will improve the reliability level of machining center during operational process.5?A software system is development using Matlab GUI language,which can realize failure data administration,statistical analysis,reliability assessment and reliability prediction.