The three inputs to an MRP system are the authorized MPS, the BOM, and the individual item inventory records. Using the CD cabinet from Figure 14-2 as our end item, let's look at each of these inputs.

Authorized MPS

The authorized MPS is a statement of what and when your company expects to build. Table 14-1 shows the first MPS record for the CD cabinet. From the MPS record, we calculate when we need to have replenishment orders of CD cabinets. We calculate the timing of MPS orders by the projected available quantity. When we do not have enough inventory to satisfy the forecast for a particular period, we need an MPS order. The quantity of the replenishment order is based on the lot sizing rule used. Table 14-2 shows the completed MPS record.

Inventory Records

To determine whether enough inventory is available or whether a replenishment order is needed, the MRP system checks the inventory records of all items listed in the BOM. Table 14-3 shows the CD cabinet's inventory record. Let's look at the information in the record.

TABLE 14-1 Initial MPS Record for CD Cabinet


TABLE 14-2Updated MPS Record for CD Cabinet


The top part of the record contains product or part identification information— typically either a part number, part name, or description. In our example, the part ...

Get Operations Management: An Integrated Approach, 5th Edition now with the O’Reilly learning platform.

O’Reilly members experience live online training, plus books, videos, and digital content from nearly 200 publishers.