Scheduling is one of the areas that received considerable attention from researchers as well as practitioners in all types of applications including operations scheduling and project scheduling. Techniques are developed to develop optimum or near optimal schedules with respect to different possible performance measures. This chapter highlights some of these techniques and their application in maintenance scheduling.
Scheduling Using Computers
It is always desirable to have a scheduling system that matches required maintenance work to available personnel and necessary equipment. The system should help maintain information of all necessary data and make them available with high reliability to build working schedules that optimizes the utilization of human resources and heavy equipment. A large number of software packages are available for optimum scheduling of personnel for planned maintenance activities and that takes into account the possibility of unplanned maintenance activities. Project scheduling packages are available to perform various functions related to project management. One of the leading packages is Microsoft Project that has the capability of maintaining data and generating Gantt charts for the projects. The critical path through the network diagram is highlighted in color to allow schedule monitoring and test alternatives.
Enterprise Resource Planning (ERP) is increasingly adopted by large enterprises as a global information and data management system to integrate the information flow through various functions within, and sometimes, outside the enterprise. The maintenance function is highly influenced by other functions in the enterprise through information flow as well as strategic directions. ERP is therefore extremely useful for integrating maintenance with production, spare part inventory, and engineering and purchasing. For more details about maintenance strategy integration in ERP see Nikolopoulos et al. (2003).
Maintenance planning and scheduling must serve the global objectives in the enterprise; hence it must be based on clear vision of its role in its success. Maintenance strategic planning is the process that assures matching between the maintenance objectives and objectives of the whole enterprise as well the objectives of other functional objectives. It selects the appropriate strategies regarding service delivery mode and type of contracts for outsourcing if needed as well as the organization and work structure and maintenance management methodology. In view of the selected strategies, long, medium and short range plans are constructed for time spans ranging from one year in the long term to weekly plans in the short term. The plans are then translated to schedules for implementing the plans at all levels. Master schedules are developed for long range plans and short range schedules are developed for days or hours within a day. Techniques exist in the literature to assist the planner and the scheduler in constructing good plans and schedules that achieve the objectives in the most efficient way. Gantt charts are usually used to monitor and control schedules. Methods like CPM and PERT are used to schedule maintenance activities forming a single large size project.