Page 187 - Orlicky's Material Requirements Planning

166 PART 2 Concepts

FIGURE 9-2
Period
Time phasing of
allocated A Parent 1 2 3 4
quantities.
Planned-Order Releases 10 15

Component

Gross Requirements 30 12 25 20
Original Status Scheduled Receipts
of Component
Item On Hand 60 30 18 –7 –27
Planned-Order Releases 27

B Parent
Planned-Order Releases 0 0

+15
+10 –15
Component –10
Gross Requirements 20 12 10 20
Allocated 10 15
Status Following
Parent Order Scheduled Receipts
Releases
On Hand 60 30 18 –7 –27
Planned-Order Releases 27

period 1 and 3 in period 2. This is accomplished with the lead-time offset available in the
bill of material (BOM) function.
Another field that optionally can be maintained in the time-phased inventory record
is the quantity past due. One time bucket immediately preceding the first period is pro-
vided for this purpose in each of the schedules (rows). In the on-hand schedule, this field
shows the current quantity on hand because the notion of past due does not apply to
these data. Past-due quantities, if any, are recorded in the respective fields, as shown in
Figure 9-3. In the computation of net requirements, the past-due quantities must be
added to those in the first period (the assumption here is that where performance fell
behind schedule, it would catch up in the first, or current, period) so as not to distort the
projected on-hand/net requirements schedule.
This is shown in Figure 9-3A. An alternative treatment is to include the past-due
quantities in the first-period buckets, as shown in Figure 9-3B. In either case, the net
requirements computation must produce identical results.