Kanban and Kanban Cards
Kanban is a concept related to the Just In Time (JIT) production and latterly Lean Maufacturing, however these two concepts are not the same thing. From a JIT perspective, kanban is the means through which JIT is managed and is effectively a signaling system, kanban uses cards to signal the need for an item i.e. kanban are used to trigger the movement, production, or supply of a unit in a factory.
The Kanban is sized so that it can only hold however many the 'customer' needs. When the operator begins work, he takes the raw material from the incoming kanban, thus signalling to the supplier (upstream) that he needs more. As such, Kanban is frequently referred to as a 'pull' system, as everything is pulled in response to past demand (as opposed to an MRP system which tend to be referred to as 'push' systems). Demand forecasts are not used in kanban systems.
The Kanban system might be visualised as a 'three bin system' for the bought-out parts - one bin on the factory floor, one bin in the factory store and one bin at the suppliers' store (in the production line). The bins usually have a removable card that contains the product details and other relevant information - the Kanban card. When the bin on the shop floor is empty, the Kanban card is removed and given to the store. The store then replaces the bin on the factory floor with a full bin which also contains a removable Kanban card. The store then contacts the supplier and indicates the need to replenish the Kanban card. The product also containing a Kanban card is delivered into the factory store completing the final step to the system. So it will never run out of product, providing of course, the cards are reliably collected from empty containers (and that the bin sizes are correctly calculated with reference to replenishment times!).
