Page 277 - Orlicky's Material Requirements Planning

256 PART 3 Managing with the MRP System

FIGURE 13-3 Current
Period
Typical load Behind
pattern. Schedule

Capacity

This pattern still can be found in the load reports of many manufacturing compa-
nies and plants. The manager evaluating the information understands that shop orders
released in the current (first) period will add their load to the second period and those
beyond, orders released in the next period will add their load to the third period and
those beyond, and so on. He or she can only estimate, or guess, what the total load in any
of the future periods will turn out to be. But this would seem to be less important than
the question of when the behind-schedule load will be worked off. It assuredly will not
happen in the current period, which is already overloaded. The manager knows, from
experience, that next period’s load report likely will indicate an overload in the second
period, which then will be current. He or she also knows that a relatively heavy behind-
schedule load appears to be a permanent condition, according to the load report. This
work center may be the bottleneck or constraint for the entire plant if this is indeed the
permanent condition.
The manager who tries to work with this type of load report may be baffled by the
curious fact that while the load report always has indicated a highly unsatisfactory capac-
ity situation relative to current and behind-schedule work load, shipments of the prod-
uct have been more or less on schedule. Accordingly, he or she views the load data with
healthy skepticism and is loath to act on the information provided by the load report. The
load pattern illustrated in Figure 13-3 constitutes virtual proof that the load report
exhibiting it is
1. Incomplete because it fails to include load that will be generated by planned
orders
2. Invalid because priorities are not being kept up to date