Fms Process System Reliability Analysis

FMS (Flexible Manufacturing System) has the advantages of high facility availability, short producting cycle, low manufacturing cost, strong adaptive capacity to producting variation, etc, which makes it suit many varieties, middle or small batch production. However, in our country, sometimes the qualification rate of some FMS is poor during the machining process, which affects the in-time accomplishment of some equipment types and the system' s economical operation. The reason is mainly because of the low reliability of the technological system, thus causes the falling short of some index required by the user like machining precision. Therefore the reliability of technologic system of FMS directly impacts the practicability of FMS. There are few research on technological reliability of FMS around the world, the thesis researched into the technological reliability of FMS. The main research efforts are summarized as follows:(1) Presents the definition of the reliability of technologic system of FMS and its criteria system(major as technological stability, technological heredity, technological reliability reserve, system reliability and so on) and the corresponding calculating methods for the reliability of technological system of FMS(the criteria are measured by the synthetical process capability index, synthetical correlation coefficient, synthetical reliability reverse index, etc) are presented. All of the criteria and the methods have been applied on ChangChun FMS machining data to get analysis result.(2) The new method of analyzing the main influence factors of the technological system's reliability from the final measuring data of machining products is presented. After analyzing the workpieces, the machining quality could be improved only by controlling the holes or lines corresponding to the main influence factors, therefore it could lower the difficulty in the control of technological quality. The approaches of multivariate statistics (three new methods: minimal variance based major factors finding method, inner class regression method and clustering regression method) to analyze the factors affecting the machining quality are presented. Based on the association of the system structure graph analysis and AHP, the practical method to analyze the main influence factors' significance is presented. This thesis used these methods to calculate and analyze the machining data of ChangChun FMS, and compared the results of different method, and the main measures to improve reliability of technological system of ChangChun FMS are summarized.(3)Centered on the factors affecting the machining precision and surface quality, the major influence factors to the reliability of technological system of FMS and the corresponding technological measures are systematically summarized, and the experiments design method totake the effectiveness evaluation of the modifying measures is given.