Page 223 - Orlicky's Material Requirements Planning

202 PART 3 Managing with the MRP System

FIGURE 11-2
Period
Transient
subassembly B, 1 2
its parent, and
component.
Schedule Receipts
Part A On Hand

Planned-Order Releases 20

Gross Requirements 20
Allocated

Part B Schedule Receipts
On Hand 2 –18 –18
Planned-Order Releases 18

Gross Requirements 18
Allocated
Part C
Schedule Receipts
On Hand 30 12 12

Following release of the planned order for A, the update procedure for item record
B will vary depending on whether or not it is coded as a phantom. In the absence of such
a code, regular logic applies. The regularly updated records of items A and B are shown
in Figure 11-3.
Record C continues unchanged. Following release of the planned order for B, item
record C is updated, as shown in Figure 11-4.
Had item B been coded as a phantom, all three records would have been updated in
one step, as illustrated in Figure 11-5, as a result of the planned-order release of item A.
Note that the release of planned order A, which normally would reduce only the corre-
sponding gross requirement B (as in Figure 11-3), in this case also reduces the gross
requirement for C as though C were a direct component of A.
Note also that the two units of B in stock (perhaps a return from a previous overrun)
are applied to the gross requirements for A and that the allocation has been distributed
between B and C. On closer examination of these examples, it can be seen that the phan-
tom logic is nothing more than a different treatment of allocation. (Zero-lead-time and