Inside a warehouse

A warehouse (or distribution centre, when goods move through quickly) is where stock waits between being made and being sold. Almost every one runs the same flow, from the inbound doors to the outbound ones.

Receiving is unloading trucks at the dock and checking what arrived against the advance shipping notice (ASN) or purchase order: right items, right quantity, no damage. Putaway is moving the goods to a storage location and recording where they went. Then they sit in storage, on pallet racks, shelves or the floor, until they're needed.

When customers order, picking takes the right items out of storage. Packing puts them in a box with the paperwork and labels, checking nothing's missing. Shipping loads them onto the right truck. The time from goods arriving to being ready to pick is called dock to stock, and good warehouses do it within a day.

Where things are kept matters. Slotting is deciding which item goes in which location. Fast movers go near the packing area at waist height (the golden zone), so pickers walk and bend less; slow movers go high up or at the back. Re-slotting as sales change can cut walking a lot, and walking is often half a picker's day.

Some goods should never be stored at all. Cross-docking unloads inbound trucks and moves goods straight across the building to outbound trucks, sorted by destination, often within hours. Supermarkets use it to get fresh food from many suppliers to many shops quickly. It saves storage and handling, but needs good timing and information.