What does the element 'Signal Kanban' indicate in a Kanban system?

The element 'Signal Kanban' in a Kanban system is essential for indicating the need for material replenishment. This concept is central to Lean manufacturing and is used to balance the flow of materials in a production process. When a Signal Kanban is triggered, it communicates to upstream processes or suppliers that additional materials are required to keep the workflow uninterrupted. This mechanism helps to reduce excess inventory, minimizes waiting times, and ensures that resources are available precisely when they are needed, enhancing overall efficiency.

In a well-functioning Kanban system, the visual signals created by Signal Kanbans help maintain a smooth flow of resources without overproduction. This aligns with Lean principles that emphasize waste reduction and optimal resource utilization.