A new mathematical model approach with assembly line feeding based Milk-Run system

Graphical/Tabular Increasing competition necessitates eliminating non-value-adding activities, with lean production emphasizing efficient intralogistics through just-in-time delivery. This study examines a freezer (Figure A) manufacturing plant in the Kayseri Free Zone, where increasing product variety has complicated material transportation. The plant's two-stage process, using forklifts or pallet jacks, often results in unplanned transportation, causing line imbalances and time losses. To address these inefficiencies, a mixed-integer mathematical model was developed to balance multi-product assembly lines and synchronize material feeding. Implementation of the model improved intralogistics, minimized delays, and enhanced production efficiency, demonstrating the effectiveness of planned logistics in achieving lean production goals. Purpose: Increasing competition in the production and service sectors has made the elimination of non- value-adding activities a critical priority. Lean production philosophy emphasizes removing unnecessary movements and transportation processes, making efficient intralogistics planning essential. This study aims to optimize the logistics processes of a freezer manufacturing plant located in the Kayseri Free Zone, which operates with two assembly lines. Theory and Methods: A mixed-integer mathematical model was developed to address imbalances caused by unplanned transportation and to synchronize the feeding of multi-product assembly lines. The model was implemented to optimize material delivery, reduce delays, and streamline production flow. Results: Implementation of the mixed-integer mathematical model significantly improved the intralogistics processes at the plant. The optimized transportation plan minimized delivery delays, balanced assembly line operations, and reduced unnecessary material movements. Conclusion: The proposed model demonstrates apractical and scalable solution for managing material flows in complex manufacturing environments, underscoring the importance of planned and synchronized logistics processes in achieving lean production goals.