LOT SIZING IN FLOW SHOP ENVIRONMENT: MODEL AND MIP-HEURISTICS

This work proposes a mixed-integer programming formulation for the integrated lot-sizing and scheduling problem in multi-stage hybrid flow shop environments. The proposed model, referred to as CLSP-HFS, accounts for parallel machines with restricted eligibility, limited capacities, sequence-dependent setup times, and closed transfer between stages. To solve the problem, relax-and-fix and fix-and-optimize heuristics are implemented. Computational results show that the CLSP-HFS formulation is competitive with some well-known single-stage models from the literature, and that the heuristics enhance its applicability in multi-stage settings. In particular, heuristics based on the fix-and-optimize strategy stand out for the quality of the solutions obtained and their computational efficiency.