The TDASys
Difference Between Scheduled
and Projected Castings for
Production Control.
Clearly the most powerful
Production Control function in the entire Global Shop MRP system is its
ability to compare the supply and demand of parts. However, raw materials
with very long purchasing lead times will frequently cause problems. This
is because the GSS Automatic Purchasing program bases the need for raw
materials upon the demand of scheduled Work Orders. If Work
Orders, and all the necessary subassembly Work Orders, are scheduled
by Production Control immediately after a Sales Order is placed, then
Automatic Purchasing will successfully handle raw materials with very
long purchasing lead times.
However, if the Engineering
Department delays the release of a Work Order - perhaps waiting for Revision
changes - then Automatic Purchasing will not be aware of any demand for
the raw material until after the Work Orders are scheduled.
And if a required raw material has a very long purchasing lead time this
frequently means that even if a Work Order is finally scheduled with enough
time left to manufacture the parts, there may not be enough time to manufacture
parts and order the raw materials.
The Projected
demand for raw materials is calculated by taking total Sales Order Quantity
for all parts and drilling down through the BOM (Bill Of Materials) file
to project how many of these 'long lead time' raw materials
are required to satisfy that Sales Order amount. This Projected
Qty is then compared to the Scheduled Qty and to the Qty
of parts on hand.
As an example, a Scheduled
Qty of 50 with a Projected Qty of 75 and an On-Hand Qty
of 10 indicates that Scheduled Work Orders require 50 pcs,
but the total requirements will eventually be 75. There are 10 parts in
stock, so the report projects that at least 65 PCs must
be purchased to cover the Sales Order Qty.
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