Counting by bin: location first, then item

When you count by item it is easy to relax: "the books show 65 pieces, the count found 65, no difference". But those 65 pieces may lie in three different places, and at picking time a worker who cannot find the item in one bin loses time. Counting by bin changes the question: not "how many of this item are there?" but "what is in this bin?". The location code is scanned first and the item inside next, so you can see exactly where the difference arose.

Why location comes first

An example. Item X sits in two bins in the books: 40 pieces in R3-04-2 and 25 in R3-04-3, 65 in all. The count finds 40 in R3-04-2, 20 in R3-04-3 and 5 pieces in R8-11-1. The total is again 65. By item the difference is zero, but by bin there are two: minus 5 in R3-04-3 and plus 5 in R8-11-1, where the books showed no such item.

In money terms this changes nothing, but for the work it matters: the picker goes to R3-04-3, finds 20 instead of 25, stops part of an order as "out of stock", while the 5 pieces stay on another rack. Counting by bin finds hidden errors like these.

Scanning the location code adds a second or two to each bin. The time pays for itself: nobody has to leaf through the list by hand hunting for an item, and the expected items are lined up bin by bin in advance.

Bin codes and labels

A bin code should be short and unique. A convenient structure is rack, section, level, for example R3-04-2. The rules:

• the same code is written identically on the plan, in the list and on the label at the rack;
• the barcode is large and always at one height, for example on the front of the beam;
• the label withstands dust and abrasion, as paper wears out fast;
• for pallets on the floor, marks are painted or taped on the ground;
• if the warehouse is rearranged, the codes are updated in the list too.

Before the count, walk round the labels and replace torn and faded ones. A minute spent changing a label is cheaper than the ten minutes one bin can cost during the count.

The scanning order

1. Scan the bin code. From that moment all entries are tied to this place.
2. Scan each item inside and enter the quantity.
3. Close the bin and move to the next.

Plan the route as a snake: one aisle starting from one side, level by level upwards, then the neighbouring rack. That way no bin is skipped. The main rule: never scan an item before the bin code. Otherwise it sticks to the previous bin and shows up in the wrong place in the report.

Empty bins and "foreign" items

Several cases need special attention:

• An empty bin. Scan it too and mark it "empty". Otherwise you cannot later tell "was empty" from "was skipped".
• A foreign item. If a bin holds an item the books do not show there, record it where you found it. Do not move it on your own during the count; relocation is done after the count, with a document.
• A mixed bin. Each item goes on its own line.
• An item with no place. Give goods standing in an aisle or on the floor a temporary code, say "Temp-1", and put them in place afterwards.

Reading the result, and mistakes

The bin-level report gives two things. First, a list of "hot" bins that show differences again and again; these are usually picking bins, because they are handled most. Second, a list of items whose total is right but whose location is wrong. The second list becomes a relocation task the next day. Write it like an ordinary task: from where, to where, how many, who does it and by when. As a check, add up an item across its bins and compare with the total; they must match.

Common mistakes:

• An item is scanned before the bin code.
• Goods are moved to another bin during the count.
• Empty bins are skipped.
• After rearranging, the codes in the list are not updated.

Conclusion

Counting by bin takes a bit more preparation: labels, codes, a route. In return it shows exactly where the shortage is and where goods sit in the wrong place, which also affects picking speed. If your bins are marked, handing over the count is easy too: the StockCheck team counts with scanners and delivers the list of differences as Excel or PDF.