What is flow in a warehouse?

Picture a warehouse where goods arrive, go into storage, are collected for an order and leave. In a warehouse with good flow, every product does that without stopping. In a warehouse without flow, work piles up at one place and is quiet somewhere else. Employees are busy all day, yet orders still leave late.

What interrupts flow can usually be found in four places. Work handled in large batches at once, so that the rest waits. A route that doubles back or crosses. Errors that have to be repaired, with double work as a result. And a place that everything has to pass, such as one packing table for the whole floor. All of them are waste.

You improve flow by working in smaller batches, by letting routes run one way and by putting the steps close together. The spread of work over the day matters too: if all orders arrive at the end of the afternoon at once, a backlog builds up that you never clear. A good warehouse layout lays the basis, because short, logical routes keep the path of product and employee short.

To see where the flow stalls, we draw the whole stream on paper, with value stream mapping. That shows where time is lost, instead of leaving you to suspect it.

Flow is not a goal in itself. It is a way to see whether the warehouse works well: when an order moves through smoothly, little is wrong. Read how we improve that in practice at improving warehouse processes.