Scheduling in a flexible job shop with continuous operations at the last stage

This paper presents a special flexible job shop scheduling problem which has continuous-operation constraints at the last stages. In other words, jobs at the last stage which need the same machine must be processed one by one without intervals. An integrated approach combining the simulation of production processes and the genetic algorithm is used to solve the problem. The processing paths of all jobs are decision variables and designed to be one individual in the genetic algorithm. The simulation with the reverse process flows evaluates the feasibility and fitness values of jobs. A satisfactory solution can be got after evolution. Finally, we apply the proposed approach to one steel-making plant.