Real-Time Condition-Based Maintenance of Friction Welding Tools by Generalized Fault Trees

Abstract

In manufacturing processes, root cause analysis of tools’ failures is crucial to determine the system reliability and to derive cost minimizing strategies. Condition-based maintenance (CBM) is one of the relevant policies to reduce costs of tools usage subjected to degradation processes. In a previous work, the authors introduced a new statistical methodology entitled Generalized Fault Tree (GFT) analysis that demonstrated good results for reliability analysis and root cause analysis. In this work, we propose a new dynamic CBM methodology, through real-time failure forecasting of the replacement instant of friction welding tools at a Bosch TermoTechnology facility, based on the dynamic update of the GFT root probability. The GFT structure is described by data-driven basic events (BEs), obtained from an embedded accelerometer, and the tree that best describes the tools’ failures is obtained through a new training process that employs a pruning technique to reduce computational complexity. The results show that we can reduce at least 12% of the costs per welding cycle by applying the GFT approach and CBM, when compared with the current policy of preventive maintenance in (optimized) constant cycles replacement periods.