Reconfiguring a mixed-model robotic assembly line considering lifespan, obsolescence, and retrofit in a manufacturing 4.0/5.0 environment

This paper addresses the challenges of reconfiguring mixed-model robotic assembly lines to face volatile market demand, new products, and technological innovations from the Manufacturing 4.0 and 5.0 Industries. The literature extensively studies designing new manufacturing systems or balancing reconfigurable ones. However, to adapt existing lines to these issues, considering lifespan and obsolescence remains an underexplored domain, along with the emerging trend of retrofitting in-house resources. A multi-step MILP-based method is proposed to bridge this gap. An exhaustive set of scenarios is compared with exact and heuristic benchmarks. The method’s effectiveness is evaluated in a large-scale industrial case study, assessing the influence of flexibility on the system. This real-world industrial case is optimised, achieving an average improvement of 4.69% over the conventional approach and better results in more than 82% of instances. Furthermore, a statistical analysis is conducted and reveals the correlation between robots’ task accessibility and their assignments. In a complementary way, a financial assessment and bottom-up analysis from Process Engineering have also been explored. Therefore, this research provides a method to reconfigure manufacturing lines considering variable operational conditions and practical issues. This leads to several managerial insights and contributes to more sustainable and profitable assembly systems.