Backflushing consumption


What is and when we will be using backflushing consumption? Method for issuing (reducing on-hand quantities) materials to a manufacturing order. With backflushing, the material is issued automatically when production is posted against an operation. The backflushing program will use the quantity completed to calculate through the bill of material the quantities of the components used, and reduce on-hand balances by this amount. 

Things to consider …

  • When manufacturing requires long lead time: this will mean that stock won’t be correct from the time it is actually used in the shop floor until production is finished (and consumption is backflushed)
  • Check impact on inventory accounts, on hand balance, planning
  • Items should be those where we always have inventory for
  • When we are using item tracking on the components: this means that lot/serial needs to be entered
  • BOM and routing accuracy is critical since it triggers consumption
  • If this is a multi-level and partner customized to backflush the entire bom levels: why not using a production order with one single line?

What NAV design is on this topic? Manufacturing Training material provides the following explanation: When you use the backward method, this is based on actual quantities. Having this in mind, if you scrap, you might want to take care of this since backflushing is based on actual quantities and once you manually post scrap, NAV expects you to manually post actual consumption as well.

Comments (2)

  1. mark.hamblin@pacesettersolutions.com says:

    One thing to keep in mind when using back flushing (or forward flushing) is that NAV does not take any manual consumption into account.  I.e., it will consume material regardless of the "remaining quantity" required.

    For example, a prod order requires 2 of component "A", and "A" is set to back flush (on purpose or by accident).  If you manually consume 2 of "A", NAV will still back flush another 2 on output or finish (depending on setup).

    This can cause unintentional over-consumption of components, and can be very painful to fix if the flushing occurs when finishing the prod order.

    One could argue that this is or isn't appropriate behaviour, but my preference is that back flushing (or forward flushing) does not over-consume material.  There are fairly easy mods that can be done to prevent over-consumption, or you can just have logic that sets the flushing method on the component(s) to manual if manual consumption is posted.

  2. Malcolm Johnson says:

    NAV does not handle flushing in Warehouse controlled area well, in especially the concept of Forward Flushing does not work well.

    In many organisations the issue of material from the warehouse into production is seen as consumption in that once the material is in the production area it should go into WIP and the requirement / usage should balance to zero assuming that all material has been picked. However the option to Flush based on Pick and Forward relies on:
    1. That Routing Link Codes must be used
    2. That an operation is triggered on the routing or output
    If you look at other ERP systems like AX the action of registering the Pick will trigger the consumption of the material.

    For our customers we often modify NAV to trigger the consumption of material on completion of the Pick for the quantity picked

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