Chapter 11: Integration With Material Requirements Planning
Master scheduling is so integrated with the rest of the business that it is often confused with other business system elements. Making it more confusing to the untrained eye, master scheduling also uses calculations and methodology similar to the material requirements planning (MRP) engine. They are about as alike in principle and practice, however, as night and day. That said, many companies do not treat the master schedule with the stature it deserves and the stature that is required from high-performance enterprise resource planning.
MRP is really the execution process in the schedule planning methodology. Master scheduling is the prerequisite planning process. Figure 11.1 shows that the real decisions are made in the master production scheduling (MPS) process, not in the MRP or materials planning phase of planning. In businesses where the MPS discipline does not exist, these important decisions are left to the planners. It is almost impossible for a planner who only sees a portion of the business to plan for the entire capacity picture. Most businesses have more than one planner, and they are not always crisply separated by product. In many of these businesses, some products have overlap in common processes, shared machinery, or components. Only when a business is very small does it normally work well for the material planner to also play the role of master scheduler. One such business manufactures saw blades for cutting concrete and blacktop. The business is small enough to have one planner do all the supply chain ordering...