Optimal scheduling method for a bell-type batch annealing shop and its application

The production scheduling for a bell-type batch annealing process in heat treatment of steel coils is a typical multi-machine multi-stage re-entrant problem with complex constraint of resources including energy source. It is very difficult to build its mathematical model due to the large number of constraints in the process. This paper proposes an optimal scheduling method for the bell-type batch annealing process that combines an improved genetic algorithm with discrete event simulation techniques. The optimal scheduling method developed in this paper has been applied to the annealing shop in Shanghai Baosteel Yichang Sheet Co. Ltd, China, for nearly 2 years. The industrial application result shows that the proposed optimal scheduling method improves production efficiency and gains economic benefits.