A two-stage hybrid flowshop with uniform machines and setup times

In this paper, we consider a two-stage hybrid flowshop in a group technology environment. We assume that parts are grouped into families and a major setup is required when a machine at either stage starts to process a new family. While Stage 1 contains a single machine, Stage 2 contains multiple uniform machines. The objective is to minimize the total makespan. The problem is derived from a real company. To solve the problem, we develop two heuristics and eight effective sequencing rules to assign the parts to the machines at both stages. We also present a model to examine the trade-offs between the costs and the speeds of the machines at Stage 2. Extensive computational results are finally presented to compare the two heuristics and to study the impact of the sequencing rules on the makespan.