Abstract:

The occurrence of CNC machine tool's failure is random, and the failure effect is fuzzy. Traditional criticality analysis is based on the arithmetic product of basic failure rate, failure mode probability value and failure effect, and the criticality analysis result can only reflect the average degree of criticality within a certain period. To solve this problem, a dynamical criticality analysis method based on random and fuzzy theory was proposed. So the randomness of failures and the fuzzy of failure effects can be comprehensive considered, the contribution of each factor to the analysis result can also be considered, and multiple effect factors analysis can be carried on. Taking the six subsystems of some certain CNC machine tool for example, proposed method was proved to be accurate and effective and has high application value in the reliability research of CNC machine tool.

Key words: machine tool, randomness, fuzzy method, dynamical criticality