Pull System: Make Only What's Needed, When It's Needed
A pull system works like a restaurant kitchen: you only start work when the next step in the process places an order. This approach, core to lean manufacturing and Kanban, prevents overproduction. The footgun is pulling new work before finishing old tasks.
THE MENTAL MODEL: A pull system produces only what has been consumed by the next step in a process. Think of a restaurant kitchen versus a cafeteria. A cafeteria pushes food out under heat lamps based on a forecast. A restaurant kitchen pulls ingredients to cook a dish only after a customer's order (the signal) arrives.
HOW IT WORKS: A pull system relies on signals sent from a downstream process to an upstream process. In manufacturing, this signal is often a physical card called a "kanban." When an assembly line worker uses the last part from a bin, the kanban card attached to it is sent back to the warehouse. This card authorizes the warehouse to send a replacement bin. The system limits work-in-progress because new work is not started until a signal indicates there is capacity for it.
WHEN TO USE IT: Use a pull system when the goal is to improve efficiency and reduce waste in a workflow. It is the foundation of lean manufacturing and is widely used in agile software development with Kanban boards. The system makes bottlenecks visible and forces teams to address them rather than just working around them.
WHEN NOT TO USE IT: A pull system may be less efficient in environments with highly stable, predictable demand where the cost of holding inventory is very low. In such cases, a "push" system that produces large, scheduled batches might achieve better economies of scale. It's also challenging if the signal lead time is very long, risking stockouts.
ONE CANONICAL EXAMPLE: Toyota's production system, where the concept was pioneered by Taiichi Ohno. An assembly station has a small inventory of parts. As parts are used, an empty bin and its associated kanban card are sent back to the parts supplier. This is the pull signal for the supplier to replenish that specific bin, ensuring the assembly line gets exactly what it needs, right when it needs it.
Read the original → en.wikipedia.org
Get five bites like this every day.
Tezvyn delivers a daily feed of 60-second tech bites with quizzes to lock in what you learn.