Counting stock in a warehouse of reusable containers is normally a count of containers, and what is actually needed is a count of contents. Where the container states what it holds, the two are the same thing and the count is quick. Where it does not, every container has to be opened or looked into, and the count becomes a full day rather than an hour.
Counting containers versus counting contents
A container may hold one part number or several; it may be part full; it may hold a kit whose contents differ from the last kit in the same container. Where the container states the contents and the quantity, a count of containers is a count of stock. Where it does not, the count is an estimate with an unknown error, and the error is discovered at the point of use.
What the identifier has to say
Part or kit identity, quantity, and – where the contents have a limited life or a batch – which batch. Three items. Where only the first is present, the count is right and the traceability is not. Where none are present, the count is an assumption. The identifier’s content is as important as its durability, and it is usually the part that gets overlooked.
Writable surfaces and changing contents
A reusable container holds different contents on different trips, so the identifier has to change. A writable surface – a card holder, a sleeve, a wipe-clean panel – handles that and is cheap. A printed label does too and generates a re-labelling step every trip. Where contents change frequently, the holder is the better answer, and it is far cheaper to include in the tooling than to add later.
Reading at height and in racking
A container on a high shelf has to be identifiable from the floor, which means the identifier has to be large, high-contrast, and on the outward face. A barcode on the same container may be unreadable from the floor, which is why many warehouses carry both – a large visual mark for people and a machine-readable one for scanners. Where only one is used, one of the two counting methods is slow.
Cycle counting and container age
A cycle count that visits a fraction of the stock each day relies on the identifiers remaining readable throughout. Where labels wear at different rates depending on the route, the containers that have travelled most are the ones hardest to identify, and the count under-reports. Including identifier condition in the cycle count – noting containers whose mark is unreadable – converts a silent error into a visible one.
What to record when counting
Container identity, contents, quantity, and the condition of the identifier. The fourth takes no extra time and it is the one that prevents the count degrading over the years. Where the same containers are counted repeatedly, a record of identifier condition by container shows which routes are hardest on markings, and that is useful information for the next container order.
Designing the container for counting
A large flat area for a visual mark, a protected recess for a machine-readable one, and a writable surface for changing contents. Three features, all cheap at the tooling stage, and together they make the difference between a count that takes an hour and one that takes a day. Where a fleet is being specified, saying that stock counting matters is often enough to get all three included. The durability of such marks is discussed in durable marks on containers.