Scheduling of jobs and maintenance activities in an unrelated parallel machines environment

Scheduling of jobs and maintenance activities is a vital problem in a production system. In the current business environment, the competitiveness of manufacturing companies is based on their ability to response the rapid changes in demand with high quality and low costs. Therefore. in this paper, the Scheduling of jobs and maintenance activities in an unrelated parallel machines environment is studied. By considering the controllable processing times, a multi-objective mathematical programming model is presented to minimize the sum of the compression and expansion of processing times and maintenance costs, makespan, tardiness, and earliness. The multi-choice goal programming (MCGP) is applied. The problem is NP-hard, therefore, the NSGA-II algorithm is developed to solve the medium and large size instances. The obtained results from solving the proposed model with NSGA-II and comparing with the results from MCGP demonstrates that the proposed algorithm is presented a non-dominated solution set in a short time.