Optimal maintenance policies for three-unit parallel production systems considering yields.

• A new optimal maintenance model is proposed for a three-unit parallel production system. • The goal of maintenance policy is to maximize the system's yields. • We obtained the expectation yields of the system and found the optimal maintenance policy by comparing the expectation yields. • A procedure for calculations of the optimal maintenance policy is given. Many production facilities consist of multiple parallel units to facilitate the completion of production plans, yet these devices are inevitably prone to malfunctions with increased operating time. Therefore, developing the optimal maintenance policy to maximize the production capacity of production facilities is a crucial issue. This paper focuses on determining the optimal maintenance policy for a three-unit production system, aiming to maximize its yield. The optimal solution is provided based on the given maintenance policy, and a general optimal maintenance policy for the system is derived. The properties related to the optimal maintenance policy are analyzed. The proposed model offers two notable contributions when compared to existing research. Firstly, a maintenance policy based on the number of visits and yields is developed. Secondly, the parallel assumption of the system and the assumption that the subsystems satisfy any distribution are in line with reality, enriching the research on maintenance strategies for production systems. To illustrate the results of the model, a numerical example is presented. [ABSTRACT FROM AUTHOR]