Master production scheduling

The master planning module coordinates procurement, production and distribution on a midterm level. Its major decision support is about sourcing which product is produced at which location and when. Thus, in this module the master production schedule is fixed. However, it is important to anticipate the key characteristics of the lower (short-term) planning levels within this module, because otherwise inconsistent plans (for procurement, production and distribution) will result on the lower planning level. 

Hill JA, Berry WL, Leong GK, Schilling DA (2000) Master production scheduling in capacitated sequence-dependent process industries. International Journal of Production Research 38 (18) 4743-4762... 

Tang O, Grubbstrom RW (2002) Planning and replanning the master production schedule under demand uncertainty. International Journal of Production Economics 78 (3) 323-334... 

Master production schedule A long-term schedule created and maintained by enterprise planning systems that defines quantities of particular products to be produced in particular time frames based on customer demands, manufacturing capacity, and resource availability. 

The master production schedule (MPS) or some other planning document that specifies how much of each end product is required in each time period r, over some specified planning horizon involving T periods. In most practical applications, the basic time period is a week, although longer periods of a month or so may be used for periods far in the future where there is more uncertainty in the demand process (e.g., the MPS is based more on forecasts than on firm customer orders). The relationship of the MPS to the production plan was discussed in Section 2. 

The goal of advanced planning is the synchronization of constrained material and resources to independent demand. Its purpose is to create a plan that is feasible with respect to aU resources required (machines, material, tooling etc.) with sufficient operational slack to permit resequencing of work orders to enhance production efficiency. The independent demand comes from several sources, including customer orders, demand forecasts, master production schedules, transfer orders (i.e., orders from other plants), and the company s policies on safety stock. The advanced planner also considers the work order schedule already released to the shop floor as presented by the advanced scheduler. For each end-item demand, a complete requirements explosion is done using that item s BOM and... 

Venkataraman, R., Frequency of Replanning in a Rolling Horizon Master Production Schedule for a Process Industry Environment A Case Study, Production and Operations Management, Vol. 5, pp. 255-265, 1996. 

Mouse, computer, 1202 Movable magazines, 384 Movements, body, 1047 Movement kanbans, 549 Moving range (control charts), 1842, 1844 MPRSA (Marine Protection, Research, and Sanctuaries Act), 1164 MPS, see Master production schedule MRC (Multiresolution CMAC), 1780... 

The company updates the inventory according to scheduled receipts and it is fair to assume that at the end of the last week the company policy requires an inventory level of 10 laptops. Master production schedule is prepared netting the demand by inventory information as shown in Table 2.3. 

MRP is a push system that deals which resource planning in a hierarchical manner. Running MRP system relies of bill of materials and master production schedule. Demands are viewed as deterministic, varying by period. 

Capacity planning verifies the feasibility of the plans at both aggregate and detailed levels. At first stage, master production schedule feasibility can be verified in an aggregated way. After material planning is performed, capacity planning verification may induce adjustments in the detailed plans. Also, the master production schedule can be modified if capacity planning reveals feasibility problems. 

This module produces the detailed schedule, indicating which order must be released in production and when, based on the master production schedule and the associated material plan. The short-range scheduling works with finite capacity constraints. 

MRP is a push system because releases are made according to a master production schedule without regard to system status. Hence, no a priori work in process (WIP) limit exists. 

The top level hierarchical plan becomes the input for the next level of planning, which is the master production schedule (MPS) or master schedule level. This schedule is always prepared in terms of end items (i.e., what is shipped from the factory or plant). If the factory produces bicycles, then the end item is a bicycle. But, if the factory produces front wheels for another factory that assembles them onto frames, then the end item is the front wheel. Planning for the MPS is constrained by the earlier planning which resulted in the production plan. Remember that the production plan was developed in terms of product families. The MPS is very specific about the end item. For example, the production plan for an apparel factory may have scheduled 200 dozen men s long sleeve shirts for the month of January. The production plan did not specify color or design, just the family of shirts that would be produced. The MPS might then divide up these 200 dozen into specific end items to be produced in specific time periods. This is illustrated in Figure 9.3 for the month of January. Note that the shirts that are scheduled to be produced in all of the weeks of January total the 200 dozen scheduled to be produced in January. 

Master production schedule (MPS)—1) The anticipated build schedule for those items assigned to the master scheduler. The master scheduler maintains this schedule, and in turn, it becomes a set of... 

It is critical that firms be able to plan and schedule production in their own firms accurately for supply chain integration to work. The master production schedule is the outcome of all of the planning. It is the contract between one firm and its marketing department and hence the remainder of the supply chain. If one member of the supply chain cannot create a valid master production scheule and adhere to the schedule, then there is a large amount of variance within the chain and all remaining members of the supply chain must include a large amount of either spare capacity or lead time to ensure that they deliver when they agreed to. 

The master production schedule (MPS) is the detailed production plan for the end items to be produced by the plant or firm. It is constrained by the production plan. For example, if the production plan calls for 1,000 two-liter size bottles of soda to be produced in January, then the MPS is the detailed plan to produce all the different types of two-liter size bottles of soda produced in January. This may mean that 250 two-liter bottles of cherry cola are produced in week 1 250 bottles of diet cola in week 2 250 bottles of sugar cola in week... 

Figure 9.4 Time Fences in Master Production Schedules...

Material requirements planning (MRP)—A set of techniques that uses bill of material data, inventory data, and the master production schedule to calculate requirements for materials. It makes recommendations to release replenishment orders for material. Further, because it is time-phased, it makes recommendations to reschedule open orders when due dates and need dates are not in phase. Time-phased MRP begins with the items listed on the MPS and determines (1) the quantity of all components and materials required to fabricate those items and (2) the date that the components and material are required. Time-phased MRP is accomplished by exploding the bill of material, adjusting for inventory quantities on hand or on order, and offsetting the net requirements by the appropriate lead times. 

The inputs to the MRP system are the master production schedule (MPS), the bill of materials (BOM), and an inventory records file, which has both the quantity of inventory in stock and the lead times of each item. 

According to APICS, the input is a five- to ten-year business plan and the output is a 12- to 18-month master production schedule. The product of the S OP process produces tactical plans to balance supply and demand. ... 

Conventional ATP is associated with a traditional make-to-stock (MTS) production environment associated with long process lead times, relatively standard products and stable demand. In the Materials Requirements Planning (MRP) II framework, production decisions are based on the embedded Master Production Schedule (MPS), which takes into account a demand forecast, committed customer orders, existing inventory and production capacity. Hence,... 

Chu, Sydney C. K. (1995), A mathematical programming approach towards optimized master production scheduling, International Journal of Production Economics, 38, 269-279. 

---