Using a Master Production Schedule

The master production schedule (MPS) allows you to control production of key "MPS items" to help you protect your schedule from fluctuations in order-based demand (forecasts, customer orders, parent job orders, etc.). MPS is a manually created, anticipated build schedule for an item. You create it based on your expectations of demand and your estimation of resource capacity.

Defining MPS Items

Before you can create an MPS for an item, you must select the MPS Flag on the Items record for that item.

Not all items should be controlled by MPS. For example, you might use MPS to plan items for which the customer demand changes seasonally; for this item, you may want to control the plan manually rather than let MRP or APS calculate demands and create supplies (MRP and APS plan only the component materials of MPS items). You will analyze expected demand, backlog, and estimated resources and enter MPS receipts as you think necessary. MRP and APS do not plan the MPS end item, but they use the MPS receipts you enter to calculate required production and purchasing of items in the MPS item's bill of material.

You can define an item as an MPS item at any level in a bill of material. Where you define MPS items should be influenced by where you want to control supply. If you define an end item as an MPS item, you are controlling supply for customer orders, and MRP or APS create the planned orders for the components to meet that supply. If you define a subassembly as an MPS item, you are controlling supply for that level of the bill of material and indirectly affecting the end-item supply.

Defining the MPS Plan Fence

The MPS Plan Fence allows you to define a time window outside which the MPS Processor automatically plans longer-term demands, and inside which you can manually control the shorter-term demands. The length (a number of calendar days) you choose for the window should depend on how far out you want to create MPS receipts manually. Or you might use the item's lead time as the plan fence. You can define the MPS Plan Fence at three levels:

For a specific item (Items form)
For all items in a product family (Family Codes form)
For all items in the system (Planning Parameters form)

When determining the MPS Plan Fence to use, the MPS Processor starts at the Items level, then checks the family code level, and finally checks the planning parameters. If the MPS Plan Fence is blank in all three places, the processor generates exception messages but does not create MPS receipts.

Use of the MPS Plan Fence is optional; if you are using the master production schedule to create all demands/receipts manually, you can leave the MPS Plan Fence blank.

Using the MPS Processor to Create a Master Production Schedule

The MPS Processor is a utility that automatically plans longer-term demands for MPS items based on demands and existing receipts in the system. It performs these steps:

Reviews all ordered or planned customer orders for all MPS items and consumes any forecasts for those items.
Reviews all other demands, such as jobs, forecasts, transfer orders, etc., for the MPS items and determines whether existing receipts can satisfy those demands. For each unsatisfied demand, the utility compares the demand's due date to the current date + the MPS Plan Fence. Depending on whether the due date is before or after the plan fence, the utility performs one of these steps:
- If the demand is due before the current date + MPS Plan Fence, the utility generates an exception message such as "Add MPS Order." You are responsible for creating an MPS receipt to satisfy the demand, using the Master Production Schedule form.
- If the demand is due after the current date + MPS Plan Fence, the utility creates an MPS receipt automatically for the unsatisfied quantity.

The MPS Processor creates receipts only for the demand quantity that is unsatisfied after the plan fence. For example, if the item's projected on-hand is 50 below safety stock at the plan fence date and there is a demand for that item due after the plan fence for another 25, the MPS Processor generates an MPS receipt only for the demand for 25, not for the entire shortage of 75. You must create an MPS receipt for the shortage of 50 using the Master Production Schedule form.

Scheduling the MPS Processor to Work with MRP or APS

The MPS Processor does not pass demands down to the components in an MPS item's bill of material. For example, if item A is made from 1 item B and 1 item C, and the MPS Processor sees a demand for 10 of item A, it creates an MPS receipt only for item A. However, when you run MRP or APS Planning, the MRP or APS system (depending on your selected planning mode) creates a planned order for the component demand for 10 each of items B and C. The MRP and APS systems do NOT create planned orders for the demand for the MPS end items that were already planned by the MPS Processor. Because of this interaction between MRP, APS, and MPS, we recommend you schedule the MPS Processor to run before MRP Planning or APS Planning (you can schedule both utilities to run on the Background Queue). If you have not defined an MPS Plan Fence, the sequence in which you run the two utilities is not important.

Note: If you have MPS items that are end items and other MPS items that are used as components or subassemblies in bills of material, you should run the MPS Processor, then run APS Planning or MRP Planning, and finally run the MPS Processor again. This practice ensures that the MPS Processor is working with up-to-date data. The MRP and APS systems perform the passing of demands to the bill of material; the MPS Processor does not know about the MPS demands in a bill of material until after you run MRP or APS Planning.

Also, the APS system views MPS receipts as demands around which it must plan other demands into available capacity. You can define the planning priority of an MPS receipt on the APS Order Priority form.

Adding Receipts to the Master Production Schedule

As prompted by the exception message "Add MPS Order," or as otherwise necessary, use the Master Production Schedule form to create MPS receipts manually to satisfy demands due inside the MPS Plan Fence.

Note: When you create an MPS receipt, you can use the Planning Detail form to see the discrepancies between your MPS supply and order-based demand, just as you can with planned orders generated by MRP or APS.

Releasing MPS Receipts to Production

As prompted by the exception message "Release Order (MPS Item)," or as otherwise necessary, use the Master Production Schedule form or the Material Planner Workbench to firm MPS receipts into jobs or production schedules. The Material Planner Workbench allows you to firm many receipts at the same time.

Including MPS Receipts in the Schedule

If you need to schedule the resources required for producing the quantities of your MPS receipts, you must include the MPS receipts in the processing performed by the Scheduling activity.

The Scheduling activity includes MPS receipts in the schedule only if you select the Schedule MPS Orders option on the Scheduling tab on the Shop Floor Control Parameters form.

MPS Process

Maintain your master production schedule using a process like this:

Schedule the MPS Processor to run nightly (as described above).
Each day, review any exception messages the MPS Processor generated.
Use the Master Production Schedule form to create MPS receipts to satisfy shorter-term demands.
Use the Master Production Schedule form or Material Planner Workbench to release MPS receipts to production by firming them into jobs or production schedules.