Kanban

Kanban is a visual method for managing workflow. It originated in Japanese manufacturing. The system uses signals, called "kanbans," to control production and inventory levels. These signals can be physical cards, colored bins, or digital alerts. The core principle is to produce and move items only when there is a downstream demand. This creates a "pull" system instead of a "push" system.

On a shop floor, a Kanban system limits the amount of work-in-progress (WIP). Each stage of production has a set capacity. A new work order is only "pulled" into a stage when an existing order is completed and moves to the next stage. For example, a two-bin system for fasteners is a simple Kanban. When an assembler empties the first bin, that empty bin is the signal to replenish the stock. They use the second bin while the first is refilled.

This approach helps prevent overproduction, a major source of waste in manufacturing. It makes bottlenecks visible because work will pile up before the constrained process. By matching production directly to consumption, Kanban reduces inventory holding costs. It also improves flexibility to respond to changes in customer demand.

To implement Kanban, teams map their workflow into distinct stages. They then place explicit limits on the number of items allowed in each stage. The team agrees on rules for when to pull work from the previous stage. Starting with a physical board and sticky notes is a common way to begin. Digital Kanban systems are also used to automate signaling and track metrics.