Study On Reliability For Machining Center

Currently the level of domestic Machining Centers is lower than that of the similar products overseas and cannot compete with them. Otherwise, the failure of Machining Center can influence the efficiency of production and may lead to accident, which could create injuries and deaths of people. Therefore, it is important to improve their reliability for increasing the national prestige, enhancing competitive ability in the international market, raising national manufacturing techniques as well as preventing accident. This thesis studies on reliability for Machining Center, taking a kind of domestic Machining Centers for example.(1) According to "Procedure for failure mode, effects and criticality analysis", FMEA method is used to analyse the faults and effects of Machining Center, and CA method is used to calculate the criticality of all subsystem, based on the collected data of failure in the Machining Center.(2) Based on the plan established for the study on reliability in the test, failure data of the Machining Center have been collected. And the distribution type of the data is judged initially. Then maximum likelihood method was used to estimate the parameters and Kolmogorov-Smirnov test was also used for testing distribution. At last, the distributions which the failure data of the Machining Center conform to are defined.(3) MTTFF, MTBF and MTTR are choosed to be indicators of Machining Center systems'reliability. All these indicators can reflect inherent reliability, using reliability as well as influence of repairment for the Machining Center system. The weight of indexes is determined by using analytic hierarchy process (AHP). At last, the indicators of reliability in the kind of Machining Center are comprehensively evaluated by the entropy weight and fuzzy comprehensive evaluation method.(4) Pointed out that the reliability design of machining center system is necessary. The basic principles of information theory are used to predict the limit of machining center system reliability, combining with Bayesian methods. And reliability is allocated to the machining center system, in meeting the target under the conditions of reliability and the minimum cost of machining center machining center as a principle of system reliability allocation.