The Reliability Time Model And The Maintainability Index Evaluation Of The NC Machine Tool

1.Purpose Based on the subject of Hi-Tech Research and Development Program of China --The research and development on the key reliability-technology of Computer Numerical Control(CNC) equipment and system , put forward the scientific research of this thesis. On the basis of the NC lathe test examining Through nearly one year , carrying a series of research on the NC machine tool failure interval time model, the NC machine tool sampling plan and the NC machine tool Maintaining stationarity. 2. The NC machine tool failure interval time model The analysis on data is the foundation of setting up mathematics model. In order to meet the needs of calculating the Informationization, my articlet is on the basis of summarizing to the traditional probability paper of weibull,put forward a situation that the sample is more in figure, method that needn't take the tradition to draw weibull probability paper by hand, then draw weibull probability picture utilizing MATLAB. Straight line of fitting through the failure data, Confirm the Parameter of the model of interval time of the failure directly. Set up weibull 's two parameters mathematics model. This method is full of the mathematics model theory on numerical control lathe failure time analysis. 3. The NC machine tool sampling plan and grouping analysis Basing on the actual conditions of the the NC lathe uses, meeting with the simple, convenient and practical demand, Select simple random sampling method to arrange sampling plan. Examine random properties of the sample data through visiting distance method. Prove the course is a continuous radom process to sample.at the same time, Explain characteristic and trend that this lathe failure and maintain time is base on the Function curve of failure probability density,the Function curve of Crash rate and Function curve of Maintain degree.