Hybrid flow shop scheduling as a multi-mode multi-project scheduling problem with batching requirements: A real-world application

We consider a real-world multi-mode multi-project scheduling problem in which the resources form a hybrid flow shop consisting of 16 production stages. Furthermore, sequence-dependent setup states arise at two produciton stages leading to a batching problem. The objective is to minimize the weighted tardiness. A mathematical model based on the well-known resource constrained project scheduling problem is presented to provide a formal description of the problem. As problem instances consist of about 30,000 jobs a heuristic solution procedure using dispatching rules is applied. We describe how these rules are modified in order to form batches.