Integrated analysis of productivity and machine condition degradation: Performance evaluation and bottleneck identification

Machine condition degradation is widely observed in manufacturing systems. It has been shown that machines working at different operating states may break down in different probabilistic manners. In addition, machines working in a worse operating stage are more likely to fail, thus causing more frequent down periods and reducing the system throughput. However, there is still a lack of analytical methods to quantify the potential impact of machine condition degradation on the overall system performance to facilitate operation decision making on the factory floor. In this article, we consider a serial production line with finite buffers and multiple machines following Markovian degradation process. An integrated model based on the aggregation method is built to quantify the overall system performance and its interactions with machine condition process. Moreover, system properties are investigated to analyze the influence of system parameters on system performance. In addition, three types of bottlenecks are defined and their corresponding indicators are derived to provide guidelines on improving system performance. These methods provide quantitative tools for modeling, analyzing, and improving manufacturing systems with the coupling between machine condition degradation and productivity.