A fault hierarchical propagation reliability improvement method for CNC machine tools based on spatiotemporal factors coupling

Clarifying the fault propagation mechanism is one of the key methods for improving the machine tool's reliability. However, current modeling methods usually overlook the impact of spatiotemporal coupling factors on fault propagation, leading to a limited understanding of the fault propagation mechanism. Therefore, this paper proposes a fault hierarchical propagation reliability improvement method based on spatiotemporal factors coupling. Considering the coupling effects of component comprehensive importance, fault tolerance, and failure modes on the machine tool system, a spatiotemporal fault hierarchical propagation topological directed graph model was established. Based on this, an improved method for calculating fault propagation strength was proposed to identify weak links and critical fault propagation paths. The proposed method effectively addresses the critical path identification problem across CNC machine tool systems. Comparison results demonstrate that the proposed method can accurately identify critical fault propagation paths. Furthermore, the influence of various factors on these path sequences is studied in this paper. It extends the traditional modeling methods and theories to enhance the transparency of the fault propagation process within the machine tool system. This work provides theoretical support for maintenance decision-making.