Integrating preventive maintenance activities to the no-wait flow shop scheduling problem with dependent-sequence setup times and makespan minimization

In this paper, preventive maintenance (PM) operations are incorporated as a constraint to the m-machine no-wait flow shop problem with dependent-sequence setup times and makespan minimization scheduling problem. PM are based on the concept of flexible and diverse maintenance levels (ML). Flexibility means that PM activities can be carried out in other periods besides the pre-determined. In order to ensure the diversity of each ML is determined according to different parameters of a PM policy based on Weibull distribution. A MILP is proposed to describe the problem. A procedure to assign PM activity in the sequence of jobs are proposed. As solution methods for the problem, the main constructive heuristics for the m-machine no-wait flow shop with makespan minimization are implemented in the original and adapted versions to solve small and large problem sizes. Computational results show that LWW and FCH are the best heuristics regarding the quality of solution in large problem sizes and generate the better results in small sizes, compared with the MILP solutions. In comparison with other procedures to scheduling PM operations to the sequence of jobs, the proposed procedure generates better results in all large problem sizes.