Research Of Reliability Analysis And Control Technology Of CN Machine Based On Element Action

Aiming at the disadvantages of methods studying in the CNC machine toolsreliability, the paper puts forward an analysis method based on element movement,expounds the main idea and research contents after the analysis of the relationshipbetween reliability and machine’s function. Meantime, the “function——motion——action” is been expounded with gear grinding machine as the example. Finally the geargrinding is decomposed into basic motion systems, which is the foundation to model thereliability evaluation of the gear grinding machine.In order to further study the element action reliability, the paper analyses thefeatures and factors constituting element actions, then defines the element actionreliability and describes it with mathematic symbols from the point of view of functionof actions. Meanwhile the reliabilities of all attributes and single attribute are modeledrespectively. To expound the element action reliability more comprehensive, the paperanalyses the factors including “stress——failure mechanism——failure models” andtypes of the models of e-action faults, then classifies all the common models of machinetools.Inorder to study the forming process of e-action failure, the paper describes therelation between performance parameter and defect with mathematic symbols after theconcept of defect is put forward. Because of the discreteness in the forming process ofe-action failure, the paper studies the general rule of the process from the point of viewof random variable, which is used to get the mathematic models of two kinds of gradualfailure, one has the initial value and the other has not. Finally, the formula of e-actionmean time of two failures has been deduced. Afterwards, the paper does the FMECA ofe-action which uses the action as the element level. Meantime, the densities of infectionof e-action failure models are rank ordered after dealing with the survey records and theconcept of key e-action is put forward.Finally, the paper expounds the features and structuring process of e-action faulttree which is described with mathematic symbols too. Four failure models (turning ofgrinding wheel, moving of slider, turning of idler wheel and screw rod) which have thehigh density of infection are analyzed in e-action fault tree including designing,assembly and so on. The failure causes are rank ordered by the means of qualitativeanalysis on the minimum cut sets and quantitative analysis on failure probability and importance degree of failure causes. Afterwards, the paper puts forward the controlmeasures on e-action reliability based on man, machine, material, method, measure andenvironment (5M1E). It is not hard to see that assembly process is the key link inreliability control of e-action.