The Japanese word kanban means "sign" or "signboard." Kanban is a scheduling system developed by Toyota and is now popular in many Lean organizations. Kanbans are the signals that regulate the just-in-time system of production, they are a visual signal that triggers action. They can be physical cards, electronic signals, empty bins, or other visual cues that alert people that they need to take action.
The kanban system works to meet demand and reduce the chance of overproduction and excess inventory. Implementing a kanban system can also eliminate downtime between production processes, ultimately making the manufacturing system more efficient.
When a customer orders a product, a kanban might be sent from the sales department to the production line telling them to start making more products. The production line would take action and then send a kanban upstream requesting additional materials. And so on throughout the process.
Toyota has developed six rules for applying kanban in the workplace:
- Each process issues a kanban alert to its supplier as the process consumes its supplies.
- Each process produces specific quantity and in order of incoming requests.
- Items are not produced or transported unless a request has been made.
- A kanban is attached to the item at all times.
- If an item becomes defected in the process, it is never sent to the next production process,
- Limiting the number of pending requests can make process inefficiencies more apparent.
Many types of kanban systems exist including a 1-bin system, 3-bin system, 2 card-system, and more. Some kanban systems expand beyond a business itself to its suppliers. An electronic kanban system, for example, might send an automatic email request to a supplier when more of a particular part is needed. Kanban cards and bins typically correspond with a kanban board. These boards are broken to different sections such as “To Do,” “In Process,” and “Done,” helping people see work in progress.