A New Method of Failure Analysis of the Feed System of CNC Milling Machine Based on Triangular Fuzzy Number

In order to solve the problem that classical criticality analysis can't indicate randomness and fuzziness of mechanical failure, a new method of failure analysis is presented based on triangular fuzzy number. Considering influence of fault frequency, maintenance costs, maintenance time, fault effect, decision matrix is established with triangular fuzzy number. In order to reduce subjective influence of determining weights by experts directly, linear programming equations are established to obtain weights by Hausdorff distance. Finally, through establishing possibility degree matrix at different levels of risk attitude, criticality rank of each failure mode is obtained. Taking a case study of XK7132 CNC milling machines, the results show that bearing failure is the most hazardous failure mode. Compared with classical criticality analysis, method in this paper is more scientific and reasonable, and provides a theoretical basis for improving reliability of CNC milling machine.