Formulation and MIP-heuristics for the lot sizing and scheduling problem with temporal cleanings

We propose a novel mixed integer programming (MIP) formulation for a real-world lot-sizing and scheduling problem commonly found in the production of fruit-based beverages, dairy products, among others. The model entails synchronized two-staged production, mandatory temporal cleanings, and sequence-dependent changeovers. In this paper, it appropriately represents industrial production processes of pasteurized juices and fruit flavored juices of different companies. One of the main modeling challenges is to synchronize the two stages that have different temporal cleanings in each stage and are directly connected only when the beverage is being completely transferred from one stage to the other. To the best of our knowledge, there are no studies in the literature that propose MIP formulations for this problem. We also devise fix-and-optimize MIP heuristics to solve realistic large-scale instances from a large worldwide brand company. Computational tests show that they are competitive when compared to the model and the company solutions.