In the manufacturing world, production planning and control features four stages: Routing, Scheduling, Dispatching, and Follow Up. The first two relate to production planning while the second two relate to control. Planning and scheduling are directly associated with time and capacity management, a major factor in enhancing shop floor efficiency and business results, and the second stage of production planning and control (PPC). Knowing this, let’s focus on the scheduling stage specifically and the different methods used to approach it: master production scheduling and manufacturing and operation scheduling.
Master Production Scheduling
Master Production Scheduling (MPS), otherwise known as an over-all schedule, focuses on a planning horizong, divided into equal time periods (time buckets, such a by month). It includes a plan for the production of individual commodities such as staffing, inventory, etc for the allotted time period. A MPS usually dictates when and how much of each product is going to be produced, based on criteria such as demand, capacity, and inventory availability.
MPS aids in decision making by generating a set of output data based on forecast demand, production costs, inventory money, customer needs, production lead time, and capacity. The resulting output information includes the amounts to produce, staffing requirements, quantity of product available to promise, and projected available funds for production. It also sets the expectations of the revenue that the business is likely to generate.
Manufacturing and Operation Scheduling or Detailed scheduling
Manufacturing Scheduling (sometimes called detailed scheduling or production scheduling) focuses on a shorter horizon than MPS. It also fixes a time and date to each operation in a continuous timeline rather than in time buckets, defining the start and completion time-frame for each process. Both subsequent stages of production planning and control depend on this timeline which makes it a very valuable asset in the production process. Scheduling looks to optimize the use of time; from each piece of work involved to project planning to customer delivery. The goal is to maximize thruput (output) and on-time delivery, within the constraints of equipment, labor, storage, and inventory capacity. This usually includes focusing on maximizing utilization of critical bottleneck resources by minimizing changeovers and cleanout and also avoiding material starvation. In order to schedule more efficiently, there are a variety of methodologies and tools that planners can apply.
Master Scheduling and Production scheduling work in concert to create capacity and inventory plans that maximize a business' resources to serve its customers efficiently. Proper use of scheduling methods results in enormous benefits for a manufacturing business. Efficient planning and disciplined schedule execution on the shop floor can have impacts of up to 25% or higher on output and on-time delivery. Failure to systemetize this process can result in lost customers due to late delivery and excessive lead times, cash flow problems due to delayed shipments, and stressful operating environments due to chaotic, reactive resource and order management.