Small Sample Maintainability Analysis of CNC Machine Tools

With the continuous improvement of the reliability of CNC machine tools, some subsystems of CNC machine tools show the characteristics of long life, less faults and less maintenance. In these long-life subsystems, not only the maintenance data distributed in each subsystem is less, but also the prior information about the maintainability of the subsystem is less. In view of this situation, the lognormal distribution model is transformed into a normal distribution model, and a normal distribution small sample modeling method without prior information is used to establish the maintainability model of each subsystem. It can be found that the MTTR of exchange table is the maximum, and the maintainability level is the lowest through the maintainability evaluation results. The conclusion lays a foundation for the improvement measures of machining center credibility.