Page 133 - Orlicky's Material Requirements Planning

112 PART 2 Concepts

are developed be fore the next-lower level is netted. This means that the component’s
require ments need not be reprocessed and renetted subsequently owing to emergence of
another gross requirement generated by another parent item. The fore going applies pro-
vided the component item in question appears on only one level in the product structure.
Some items, however, may appear on two or more different levels. This leads to the next
complicating factor.

Multilevel Items
Recurrence of gross requirements for a given item during the require ments-computation
process may be caused by the fact that the item’s sev eral parents are on different BOM
levels. Because a component item, by definition, is always on the next level below its par-
ent item, this means that whenever an item’s parents appear on more than one level, the
item itself has multiple levels associated with it. There are two cases: An item may exist
on different levels in the structure of different end items that use it in common (Figure
6-10), or it may exist on different levels in the structure of one end item (Fig ure 6-11). In
a given case, both these conditions may exist at the same time. The problem here is one
of having to reprocess and renet at every recur rence of gross requirements stemming
from parent items that appear on multiple levels. This would mean multiple retrievals of

FIGURE 6-10 Level End Item End Item
Existence of 1 X Y
common
components on
different levels.
2 A

3 A

FIGURE 6-11 Level End Item
An end item’s 1 Z
components on
multiple levels.
2 A

3

4 A