Backflush Causes Input Bin to go negative

If I understand the hierarchy of backflushing bins, it appears that it should not backflush from a bin location that has a negative quantity. It keeps going down the list until it finds a bin with a QOH. I am not finding that to be true of the actual backflushing, though. All of our parts have negative quantities in the bin location defined in the In/Backflush bin (same bin) but it just keeps pulling them from that same location. I was really hoping it would get to the Primary bin for the part and pull from there. I feel that would be how I’d expect it to work anyway.

We do allow negative QOH. Does that change how the logic works for Backflush? Any advice is appreciated.


If you make a bin “stop” on negative QOH, then it will not allow you to do a transaction that is for more than the bin contains. For us (FIFO) the only caveats to this are: backflush and kanban.

I believe backflush location works from the resource level (or resource group) for the operation that has the backflush part.

Upon looking at the documentation, I would be led to believe it would not process the transaction if the bin QOH was negative. Our default In and Backflush bins are both set to the same value on both the Resource and the Resource Group. So I expect that the first four bullets should fail and the fifth should be the bin it pulls inventory from. See below from their built-in help.

Are all the locations for this material in the same warehouse, just different bins? It’s still pulling from the one bin?

Yes, it seems to be a global issue. Not isolated to just certain parts. Our Epicor support mentioned to try to leave the backflush bins blank and see what that does.

Here’s an example:
This is a snapshot from a BAQ looking at our PartBin table

As you can see it has a Primary Bin defined.

But it always backflushes from the “Assign” location, which is the default input and backflush bins defined on the Resource/Resource Group. Very neg QOH balance.

I’ve never looked at the help screen :rofl: I just assumed it always came from the bin that was defined in the resource/resource group.

It seems to always hit us in that bin no matter what the logic is dictating. I’d have to try some tests to make sure though based on the the if/then scheme you put up earlier.

Just for closure, we ended up removing the backflush bin from the Resource/Resource Groups and that allowed backflush to start working as expected. Now it backflushes from the primary bin in the site that the resource is in.

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I know this is an old post but are you saying that a backflush part can drive a qty negative using the backflush labor process even though part class & bin says negative is not allowed?



We are FIFO, so as long as there is inventory in the warehouse, the backflush bin does go negative. Since the cost will be correct, all we have to do is fix the quantities.