Page 194 - Orlicky's Material Requirements Planning

CHAPTER 9 System Records and Files 173

the MRP system will not try to recompute or reposition this particular planned order the
next time the net requirements change. The transaction reporting this intervention to the
system is the previously discussed firm planned order. The change in the planned-order
schedule affects the gross requirements of component items and causes their status to be
recomputed. The firm planned order is one of several types of inventory transactions that
affect more than one record in cases of manufactured items. Purchased items have no
components (in the system), and transactions reported against them never affect other
inventory records.
Effect number 8 (reduce quantity of planned-order release and increase scheduled
receipts in parent records; reduce gross requirements and increase quantity allocated in
component records) is caused by a release of a planned order, which the respective trans-
action converts to an open order (scheduled receipt) in the inventory record. This trans-
action also affects component records, whose gross requirements are reduced and the
allocated quantity increased.
Effect number 9 (increase quantity of planned-order release and reduce scheduled
receipts in the parent record; increase gross requirements and reduce quantity allocated
in component records) nullifies a previous order-release transaction. This happens when
the inventory planner for some reason decides to rescind the release of an order. Once a
shop order has started into the manufacturing process, this, of course, is no longer possi-
ble except in very unique circumstances.
Effect number 10 (change quantity of planned-order release in the parent record and
change quantity of gross requirements in the component records) is caused by the only
internal transaction that exists, that is, a change in a parent planned-order schedule being
reflected in the gross requirements of component items. This effect is identical to effect
number 7 except that here the “transaction” is generated by the system internally in the
course of requirements planning (explosion).
As pointed out earlier, different transaction codes may be used for several entries
that are identical logically, that is, that have the same effect on inventory status. The rea-
son for creating a transaction set larger than the minimum that is essential lies in the
desirability of being able to log transaction history (audit trail) by recording and mea-
suring their sources, reasons, and so on, as well as being able to trigger different treat-
ments of these various transactions in the subsidiary-data segment of the inventory
record.

Reporting Receipts and Disbursements

As mentioned in Chapter 5, an MRP system is based on the assumption that each item
under its control passes into and out of stock and that reports of receipts and disburse-
ments, that is, transactions, will be generated. In many manufacturing operations, how-
ever, it is not practical to route each inventory item through a stockroom. In fact, this can
be the source of significant waste that can be eliminated. In these cases, the reporting,
which is mandatory under an MRP system, may be based on events other than physical