Optimization framework for the simultaneous batching and scheduling of multisite production environments

Abstract

In recent years, many companies have shifted from single-site production to more complex manufacturing environments involving multiple multiproduct facilities. At the operational level, the scheduling posed on each individual facility does not lead to efficient use of resources and consequently an optimal production management over the whole production system cannot be achieved. In this context, a multisite production scheduling framework is fundamental to respond appropriately to the market requirements. In this work, a mixed-integer linear programming (MILP) model for the simultaneous batching and scheduling of multisite multiproduct batch plants with nonidentical parallel units is proposed. Given a set of manufacturing sites with unit capacities and structure known and multiple orders with associated release and due dates, the proposed approach determines the plant where each customer order must be processed, the number and sizes of batches to satisfy each order, the assignment of these batches to units, as well as the sequencing and timing of batches on each unit of the plant that processes them, in order to minimize the global makespan related to the whole production system. The application and performance of the proposed model are highlighted through numerical examples.