Page 267 - Orlicky's Material Requirements Planning

246 PART 3 Managing with the MRP System

system’s files in general and the inventory-status records in particular contain a wealth
of information that provides an opportunity for extracting or further processing the data
for a whole spectrum of possible outputs.
In the discussion that follows, outputs of an MRP system, which take the form of
reports, individual messages (notices), and displays on monitors, will be reviewed by
functional category rather than individually. Six such categories may be recognized:
1. Outputs for inventory order action
2. Outputs for replanning order priorities
3. Outputs to help safeguard priority integrity
4. Outputs for purposes of capacity requirements planning
5. Outputs aiding in performance control
6. Outputs reporting errors, incongruities, and out-of-bounds situations within
the system
Outputs for inventory order action are based primarily on planned orders becoming
mature for release. The MRP system detects such orders by examining the contents of
planned-order release buckets in the time-phased inventory records. Other types of
inventory order actions are increases, reductions, and cancellations of order quantities.
These types of outputs are self-explanatory, and the category should be the one most eas-
ily understood in light of the contents of several preceding chapters.
Outputs for replanning order priorities serve to alert the inventory planner to cases of
divergence between open-order due dates and dates of actual need, as indicated by the
timing of net requirements. Examples of data on which outputs in this category would be
based will be presented later in this chapter. In generating these outputs, the MRP system
has the capability to indicate precisely by how many periods (or days) each item affect-
ed should be rescheduled and in what direction. Under its standard implementation, the
system does not change open-order due dates automatically (although it can easily be
programmed to do so) but depends on the inventory planner to take rescheduling action.
Outputs to help safeguard priority integrity, that is, to keep order priorities not only
valid but also honest, relate problems of item inventory status to the master production
schedule (MPS). The concept of priority integrity will be discussed further in this chap-
ter. To keep priorities honest, the MPS must reflect the realities of production; that is, it
must not contain end-item requirements that it will be impossible to meet for lack of
capacity, material, or lead time. Some companies use reports in this category to provide
guidance in accepting customer orders for guaranteed delivery. Such reports are gener-
ated by trial fit (see Chapter 12) of the order into the MPS and by letting the MRP system
determine component-material and lead-time availability. If the order does not fit, the
report indicates a best delivery date alternative.
Outputs for purposes of capacity requirements planning are based on quantities and due
dates of both open and planned shop orders, which serve as input to the capacity require-
ments planning (loading) system. This function will be discussed further in this chapter.