Problema de dimensionamento de lotes de tamanho fixo com múltiplas plantas e múltiplos produtos, com troca de lotes entre plantas e transporte para clientes

Abstract

The Multi-Plant, Multi-Item Lot Sizing Problem with Inter-plant Transfers and Customer Transportation (MPFSL-CLSP-Transp.) addresses production in predetermined batch sizes and the possibility of inventory transfers between plants, in addition to transportation to customers. The problem consists of determining the number of lots to be produced for each item across different periods and plants, minimizing the sum of production, inventory holding, transportation, inter-plant transfer costs, and potential customer service delays, without exceeding available resource capacity constraints. Traditionally, a sequential resolution strategy is employed, where hierarchical decisions are made sequentially, resulting in low-efficiency solutions and elevated costs. This research proposes an integrated model that simultaneously optimizes all these decisions, overcoming the limitations of traditional sequential models. To evaluate the impact of inter-plant transfers, two models were developed: a complete model with transfers and a restricted model without transfers, enabling quantification of this functionality’s contribution to operational cost reduction. Computational experiments conducted with 24 representative instances demonstrated the superiority of the proposed integrated methodology, which exhibited superior performance in 100% of instances with transfers and 96% without transfers. The integrated model achieved 7.63% savings in total operational costs compared to the sequential model with transfers, and 4.39% without transfers, while significantly improving service quality, reaching a 99.71% service level. Comparative analysis revealed that inter-plant transfer capability not only eliminates problematic cases but also amplifies economic benefits by 74%, validating the importance of operational flexibility for maximizing gains in complex industrial contexts.