Have been meaning to write this one for a while, but kept putting it off. Recently though, I have been hearing this requirement quite a lot (no pun intended :-) ) – the ability to pick a lot that is convenient to the picker as opposed to the actual allocated lot. First, some background: Lot allocation based on lot attributes is a powerful feature in WMS. A common use case is a “strict” FIFO policy that some warehouses use to handle perishable products. The way it works currently, the WMS rules engine checks the lot expiry date and then directs the picker to clean out a lot that is the oldest in the warehouse. Obviously a very useful feature provided you are dealing with perishable products where strict lot control is essential to minimize product obsolescence.
The problem arises when you have a lot controlled product primarily for traceability but do not really need lot control for shelf life control. In other words, you want the system to recommend lots to pick based on loose FIFO but not enforce them during picking. Unfortunately, Oracle WMS gives you an “all or nothing” solution. If you decide to make your products lot controlled, you have no option but to enforce lot allocation and only pick the lots that WMS tells you to. This is often a cause for grief and heart burn at many warehouses because this could drastically impact picking.
Imagine a scenario where each pallet is lot controlled and in a 2-deep warehouse slot. WMS directs the operator to pick a pallet that is currently sitting at the back of the rack. Obviously this will have implications for warehouse productivity since the operators will spend considerable time sorting through cases or pallets to pick the right lot. If the warehouse operators want to beat the system, this may also adversely affect the inventory accuracy and lot traceability i.e. the operators confirm the lots recommended by WMS but in reality, the operators physically pick the lot that is most convenient to pick. Either way this is a grave situation.
Here are some ideas and thoughts around this situation:
Do you really need lot control?
The essential point for having lot-control is traceability and shelf life control. If your product is not perishable or has a defined shelf life or if you do not require lot attributes or full traceability of products from manufacturing to shipment and don’t do product recalls, you do not need lot control. Consuming products in FIFO mode because it’s a good business practice is not a good reason for Lot control. You can do a loose FIFO without having full lot control. You can use the receipt date and allocate down to the locator level using the rules engine without using lots.
Should you commingle lots?
Unless business reasons warrant it i.e. lack of shelf space, avoid lot commingling. If you have to commingle, at least commingle lots that have expiry dates within a tight cluster say within 30-days of each other. This way you can have a good trade-off between consuming products in FIFO mode, tighter space usage without the need to rummage through multiple cases or pallets to pick the right lot.
Is lot substitution the answer?
Maybe. WMS allows lot substitution in 11.5.10. Oracle in its infinite wisdom has chosen not to release the patch for R12. Lot substitution allows an operator to pick a different lot than what the system is recommending. It seems like a good solution but unfortunately it does not solve the problem. The reason is that the substituted lot must be freely available and not allocated for some other task. This is not a realistic assumption in a busy warehouse.
Is customization the answer?
What you really need is lot swapping - i.e. the ability to freely pick another lot regardless of its allocation status. Unfortunately you really need a customization to achieve it. Extension rather – we don’t do customizations, we do extensions. Like I said earlier, we have heard this from a few customers and are actually busy at work prototyping this and should be releasing this fairly soon. Stay tuned!
