Scan the bin first or the item first? Choosing a scan order

Put two scanning teams in the same warehouse and tell one to scan the bin label before the items, the other to scan the item first and the location after. Both will finish with a full set of records, and the two files will look nothing alike. Neither order is wrong, but the choice changes how errors show up, how hard a recount is and how long each shelf takes. Settle it before the first scan, not on the floor.

Bin first: records in blocks

The operator scans the bin label, and every item scan after it belongs to that bin until the next bin label is scanned. The exported file reads like a series of blocks: bin, item, item, item, then the next bin.

The strengths are plain:

• It needs the fewest scans, because one location scan covers every item in the bin.
• The location is attached by the device, so nobody types it.
• A recount is easy: redo the block between two bin scans.

The weakness is bleed. If the operator finishes one bin and forgets to scan the next bin label, every item that follows is booked to the previous bin, and the device cannot tell.

Item first: every line stands alone

The operator scans the item, then scans or keys in where it is. Each record is complete on its own, with item, quantity and location together.

There is no bleed, and the records do not depend on one another, so files can be re-sorted or merged in any order. It suits a SKU that is spread over many places, such as stacks on the floor, or a count that follows one fast-moving item across the whole site.

The price is more scans and a slower pace. Locations that are typed by hand pick up typing errors, and when people are in a hurry they are sometimes left blank.

What bleed looks like

Suppose bin D-07 holds 60 phone cases (A-1187) and the neighbouring bin D-08 holds 24 thermos flasks (B-0412). D-07 is open while the cases are scanned. The operator then walks to D-08 and starts scanning flasks without first scanning the D-08 label.

The export shows 84 pieces in D-07, 60 cases and 24 flasks, and nothing at all for D-08. Against the books, D-07 is 24 flasks over and D-08 is 24 flasks short. Equal size, opposite sign, and neighbouring bins: that is the signature of bleed.

The odd part is that the SKU totals are still correct, because there are 24 flasks in the building. In a SKU-level table the error is invisible. It surfaces only when someone goes to a bin looking for goods, so if the bin detail will be used later, it has to be prevented during scanning.

Comparing the numbers

Suppose a unit has 120 bins with an average of 8 SKU lines each, which makes 960 item records.

• Bin first: 960 item scans plus 120 bin scans, 1,080 in all.
• Item first: 960 item scans plus 960 location scans, 1,920 in all.

If a scan takes about three seconds, the gap of 840 scans is roughly 42 minutes of pure scanning for one team, before any walking or recounting.

How to choose

• Fixed shelves or compartments holding several SKUs each: bin first.
• One SKU in many places, or a check of a single product across the site: item first.
• A site with both shelving and floor stacks: decide by zone. Shelving areas scan the bin first; floor areas treat the pallet label as the "bin" or scan the item first. Write each zone's rule on the briefing sheet.

Use one order within a zone, or the files will have different structures when merged.

Making bin-first safer

• Make bin labels look different from product barcodes, for example a fixed prefix such as B- and a coloured edge.
• Bracket each bin: scan it at the start and again at the end. A block that opens and closes on different bins gets flagged.
• Export a file after the first hour and check the sequence of bins against the walking route. A jump usually means a skipped label.
• If the device settings allow it, have the device refuse item scans while no bin is open.

InventoryHub counts with handheld scanners that record the bin, quantity and time of every scan, and bins that do not tally are recounted on the spot, so bleed and similar problems are found the same day rather than at merge time.