A linear programming model to manage the maintenance backlog

One of the keys to a successful maintenance program in a large manufacturing industry is the ability to complete repairs in a timely fashion. A poor maintenance program impacts productivity, costs, customer satisfaction, and worker esteem. Since a substantial portion of maintenance labor-hours are assigned to non-routine work orders, it is important to process these orders promptly and effectively. A linear programming model has been developed to cost-effectively allocate labor crews to different prioritized work orders. The linear programming model gives consideration to different craft areas, such as electrical, mason, and so on, as well as to the prioritization of work orders. Also, the use of overtime work and the assignment of a special allocable projects crew is considered. The model formulation is continually updated and rerun as new work orders enter the system, old orders are completed, and the time horizon changes for the pending work orders. An example of the model is presented as applied to an aluminium smelting plant, where the model is being run successfully on a weekly basis.