Walk sequence

How a walk sequence works

Each location gets a sequence number that reflects the route. A pick list with lines in C-03-01, A-01-02 and B-05-02 is re-ordered by those numbers, not by the codes, so the picker visits them in the order they come to them.

Numbers are often spaced in steps of 10, such as 100, 110, 120, so a new bay can be slotted in later without renumbering the whole building.

Why sorting by bin code isn't enough

Bin codes sort alphabetically, but people don't always walk alphabetically. In a serpentine layout you walk up aisle A and down aisle B, so B's bays should come in reverse order. Sorted by code, the picker walks to the far end of aisle B and then back.

Walk sequence also handles layouts that codes can't express, such as a mezzanine visited between two aisles, or a cold room at the end of the route so chilled items spend the least time outside.

• Serpentine: up one aisle, down the next. Common for shelving with a single entry.
• Return: go down an aisle and come back out the same end. Common in wide pallet aisles.
• Zone order: finish one zone completely before moving to the next.

Common walk sequence mistakes

Setting the sequence once and never updating it after racks are added or moved is the most common problem. The route quietly degrades, and pickers start ignoring the list order.

Another mistake is using the pick sequence for heavy and fragile items without thinking about the tote. If fragile items come first on the route, heavy items land on top of them. Your slotting should put heavy SKUs early on the route.

How NextStock handles walk sequence

In NextStock each location carries its own walk sequence, and walk order is the default for anything a picker or counter walks: pick lists for discrete picking and batch picking, and cycle count sheets. See order picking for how lists are built.