Performance improvement by integrating preventive maintenance and production scheduling for a two-machine flow shop

Generally, production planning includes production scheduling and preventive maintenance, and they are activities that are inter-reliant to production system but often performed separately. Recently a few scholars have studied the integrated preventive maintenance and production scheduling for a single machine, thus this study proposes an integrated model that simultaneously determines production scheduling and preventive maintenance policies in a two-machine flow shop to improve production performance by means of minimizing the total weighted tardiness cost of jobs. This study demonstrates the benefits of integration by a numerical example, and compares the integrated solution with the solution obtained from solving the production scheduling and preventive maintenance problems separately. A large samples simulation experiment shows that the two models are significant different, where the penalty cost resulted from tardiness of the integrated model is smaller than that from the non-integrated model. The sensitivity analysis shows that the preventive maintenance processing time, the repair time, and the shape parameter of the Weibull distribution are the three parameters that influence the penalty cost. Among the three parameters, the repair time has a most significant impact on the penalty cost.