A hybrid two-stage flowshop with limited waiting time constraints

In this paper, we consider a hybrid two-stage flowshop with a batch processor in stage 1 and a single processor in stage 2. Each batch processor can process a batch (limited number) of jobs simultaneously. Once the process begins, no job can be released from the batch processor until the entire batch is processed. For each job the waiting time for the second stage cannot be greater than a given upper bound. The objective is to minimize the makespan. The two-stage flowshop sequencing problem with limited waiting constraints was shown to be NP-hard. A heuristic algorithm and a mixed integer program are proposed. The results of the experimental investigation of the effectiveness of the algorithms are also presented.