Automated warehouse treatment of pallets, lots and locations
In the conversation below, SKU = Stock Keeping Unit (a Resource Type), WMS = Warehouse Management System, WCS = Warehouse Control System - sits between Warehouse Management Systems (WMS) that handle receiving/picking/shipping etc. and the conveyors and cranes that move the goods.
I got a guided tour of the facility. The conversation below is with one of the people who implemented the system.
Question: How does the automated warehousing system deal with lots, locations and pallets?
I saw people and equipment moving pallets around, and receiving and shipping pallets.
Does each pallet have an ID? Does each pallet know its contents? Or does a collection of products on a pallet have an identifier? I saw a label on a pallet being scanned. I assume that said what was on the pallet.
Answer: Yes, each pallet has an ID, bar coded which gets scanned as it moves. I think (but am not certain) that the bar code itself includes the SKU(s) and Quantity(ies). It is possible it only knows the Pallet ID and the associated SKU/Quantity data are stored in the WMS. The WMS tells the WCS what is on the pallet so they are in sync.
Q: I assume the warehousing system keeps track of whatever that is (a pallet with contents or a collection of products) and where it is at any given time, in something like aisle-row-tier (but if not that, what is the identifier of a location?)
A: Yes. The WMS knows the aisle and position (e.g. pick face 41, position 2). But when the pallet is stored in the ASRS (automated storage and retrieval system) the WMS only has a single location 'ASRS'. The WCS tracks the Level, Aisle and Position, as it is responsible for managing the pallet movement in that automated storage area.
Note - this was an implementation design decision - the WMS could have been told that specific location.
Q: Likewise I assume when shipping a pallet the label gets scanned and that says what is on the shipment.
A: Yes, that is correct (either the label or associated data)
(If any of my assumptions are wrong, please correct them.)
Q: What happens if somebody takes some but not all of the contents of a pallet and ships them? Is that allowed? Is it trouble? (I assume if allowed the info must be entered into the system somewhere.)
A: Yes, picking is often by case, leaving a partial pallet. The picking is done with scanners, which reduce the case count on that pallet and moves the picked cases to another pallet. When picking eventually consumes all the cases the pallet is deleted from the pick face.
Another implementation design decision - the WCS knows the pallet is in the pick face, but doesn't track each pick. It only knows that eventually the pallet is deleted, or returned to storage with a changed case count.
No - I don't think tracking the remaining case count has been troublesome.
Q: Also, whether a pallet with contents or a collection of products, would more than one lot ever be mixed in that collection?
A: I believe that could happen within the WMS. We made an implementation decision that pallets going into the ASRS would only have one lot code.