A novel method of key meta-action unit integrated identification for CNC machine tool reliability

Abstract

There are many parts in CNC (computer numerical control) machine tool. Considering the time and economy, it is impossible to analyse them one by one. In order to reduce the blindness of researchers in choosing analysis objects, it is necessary to identify the key parts of CNC machine tool. MAU (meta-action unit) is the smallest structure that can reflect the function and performance of CNC machine tool, so it is taken as the research object. A new method for key MAU identification of CNC machine tool is proposed, as follows. Firstly, all the meta-action units were obtained by the FMA (function-motion-action) decomposition method, and the harmfulness was selected to analyze the influence of MAU on the reliability of CNC machine tool. Secondly, fuzzy theory is integrated into RPN (risk priority number) to obtain the harmfulness of MAU. Thirdly, the subjective weight of the harmfulness about the MAU was obtained by the combination of MAHP (modified analytic hierarchy process) and optimal sequence diagram method, and the objective weight was obtained by CRITIC (criteria importance though intercrieria correlation) method. Fourthly, the subjective and objective weights were integrated by a linear weighting method, and the result were taken as the comprehensive weight of the harmfulness of MAU. Finally, the harmfulness of the MAU could be obtained by its evaluation value and weight, and the MAU with greater impact on the reliability of CNC machine tool could be obtained by Pareto principle, which is the key MAU. A CNC machine tool made in China is analysised, and the effectiveness of the proposed method is verified by the comparison of various methods and experimental analysis.