Rules for Shop Order Backflush

The shop order backflush process controls which components to issue from inventory, the quantity to issue` and the locations from which they are issued. Backflushing is triggered by the following shop order processes:

• Issuing materials for shop orders.
• Receiving shop orders.
• Reporting operations on shop orders.

To determine the locations from which to issue materials, the system uses a hierarchical set of rules. Understanding this set of rules will help you control which locations are used for backflushing. To issue components, the system looks for available inventory, until enough is found, in the following order:

1. Issue from location - The location that is identified for the specific shop order component material (either entered on a material line or defaulted from the structure).
2. Inbound locations for the identified work center - If the component is associated with a routing operation, the system will look in the locations specified as Inbound for the work center.
3. Inbound locations for the identified production line - The locations specified as Inbound for the production line.
4. Floor stock locations - If the material is stored in locations of this location type, the system will issue components from any one or more of these locations.
5. Pick locations - If the part's manufacturing attributes allow backflushing from all locations, the system will issue from any one or more of these picking locations.

If negative inventory is permitted for the site, the system will continue with the following step: 

6. The first location found for the part using the backflush hierarchy identified above shall be used for negative on hand for this specific order.

If you have specified more than one inbound location, or more than one location of a specific location type, the system looks at the expiration or receipt date of the material and uses a FIFO process to determine which location to use.

Only inventory available for automatic issue according to the part availability control on the inventory part in stock location will be available for backflush. The existence of a W/D/R Number does not affect part availability. Inventory part in stock locations for tracked parts and parts with W/D/R Numbers will not be considered for negative inventory.