Scheduling a two-stage hybrid flow shop with dedicated machines, time lags and sequence-dependent family setup times

This article concerns the resolution of a hybrid flow shop with dedicated machines, sequence dependent setup and time lags. Such a configuration is encountered in the pasta production industry. The objective is to minimize the maximum completion time of all the jobs (makespan). We first propose a mathematical model for the problem. Given the complexity of the problem, we also developed an upper bound using genetic algorithm and a lower bound in order to evaluate the GA. Computational experiments are applied to a number of randomly generated test problems. The results show that the proposed algorithm can produce results that are very close to optimal schedules if they are known or very close to the lower bounds.