Abstract
Computer Numerical Control (CNC) system can be seen as the core of manufacturing and its reliability should be paid much attention to. Soft fault of CNC system occupies a large proportion in failure, but it is hard to diagnose. In this paper, the definition of soft fault of CNC system is studied, and based on the abnormal data of multi-sample CNC systems, the induction and classification of soft fault is made. Moreover, Failure mode and effects analysis (FMEA) method is used to analyze failure module, failure mode, failure cause and failure effect of soft fault of CNC system. Defects which influence reliability of CNC system most are found out at last and it has a positive impact on CNC system products design, manufacture and use.
