Human beings influencing assembly line performance: A comparison of job rotation strategies

Industries recently have faced high uncertain market demand with a greater product variety and a shorter life cycle. The primary aim of assembly systems is to increase line efficiency by maximizing the ratio of throughput to incurred costs while maintaining high flexibility. Workers are essential in determining line performance since most assembly tasks are still manual. Consequently, worker diversity plays a critical role in the operation of an assembly line, not only in terms of efficiency and productivity, but also from a human perspective. The human factor has a significant impact on task execution times and the overall production process; in any event, few studies considered human beings in assembly line operations. This study aims to explore the effect of human beings on assembly line performance; the case of an Italian company in which workers' behavior deeply influences production performance is presented, with the aim of analyzing different alternatives for the planning strategy in order to meet this requirement. The studied assembly line consists of three manual workstations and two automated workstations. It operates in a multi-model production environment and has an imbalance level of 50%. The proposal is to manage the allocation of workers through job rotation scheduling to ensure equal treatment despite different levels of efficiency. The study outlines three scheduling alternatives, highlighting the advantages and disadvantages of each.