Journal of Industrial and Management Optimization | 2026
Authors: ŞAH˙IN M.
DOI: 10.3934/JIMO.2026058
Journal: Journal of Industrial and Management Optimization
Year: 2026
Publisher: American Institute of Mathematical Sciences
Document Type: Article
Open Access: All Open Access; Gold Open Access
Cited by: 0
The production efficiency of an assembly line depends on worker characteristics and operational constraints in manufacturing systems. In many practical assembly settings, workers are required to move between stations, making walking times a relevant component of total operational time. This study investigated assembly lines with walking workers, which were rarely examined simultaneously in existing studies, considering both walking times between workstations and workerdependent task times to analyze their joint impact on line performance. To address this problem, it was formulated as a mixed-integer linear programming model and supported by a lower bound, a constructive heuristic, and a hybrid solution strategy integrating a genetic algorithm–based metaheuristic to efficiently solve larger instances. Computational experiments were conducted using a benchmark test instances under different levels of task time variability and walking times between stations. The results demonstrated the effectiveness of the proposed method in terms of solution quality and computational efficiency. The hybrid meta-heuristic was able to obtain better-quality solutions compared with algorithms in the literature. The results also revealed how worker variability and walking times influenced the overall production rate. Higher variability in worker-dependent task durations can improve the production rate at a fixed average task time, whereas longer walking times reduce system efficiency. These findings offered practical implications for the design and balancing of assembly lines with walking workers. © 2026 the Author(s), licensee AIMS Press. This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0)
constructive heuristic; lower bound; mixed-integer linear programming; walking worker assembly line; worker qualification; worker-dependent task time