Kanban is a visual scheduling system for lean manufacturing.
It all started in the early 1940s when the first Kanban system
was developed by Taiichi Ohno for Toyota automotive in Japan. It was created as
a simple planning system, the aim of which was to control and manage work and
inventory at every stage of production optimally.
The Kanban method gets its name from
the use of kanban, visual signalling mechanisms to control work in progress for
intangible work products.
Kanban aligns inventory levels with actual consumption. A signal
tells a supplier to produce and deliver a new shipment when a material is
consumed. This signal is tracked through the replenishment cycle,
bringing visibility to the supplier, consumer, and buyer.
In contexts where supply time is lengthy and demand is difficult
to forecast, often the best one can do is to respond quickly to observed
demand. This situation is exactly what a kanban system accomplishes, in that it
is used as a demand signal that immediately travels through the supply chain.
Kanban cards are a key component of kanban, and they signal the need to move materials within a production facility or to move materials from an outside supplier into the production facility. The kanban card is, in effect, a message that signals a depletion of product, parts, or inventory. When received, the kanban triggers replenishment of that product, part, or inventory.
Three-bin system
An example of a simple kanban system implementation is a
"three-bin system" for the supplied parts, where there is no in-house
manufacturing. One bin is on the factory floor (the initial demand point),
one bin is in the factory store (the inventory control point), and one bin is
at the supplier. The bins usually have a removable card containing the product
details and other relevant information, the classic kanban card.
When the bin on the factory floor is empty (because the parts in
it were used up in a manufacturing process), the empty bin and its kanban card
are returned to the factory store (the inventory control point). The factory
store replaces the empty bin on the factory floor with the full bin from the
factory store, which also contains a kanban card. The factory store sends the
empty bin with its kanban card to the supplier. The supplier's full product
bin, with its kanban card, is delivered to the factory store; the supplier
keeps the empty bin. This is the final step in the process. Thus, the process
never runs out of product, and could be described as a closed loop, in that it
provides the exact amount required, with only one spare bin so there is never
oversupply.
If all this is confusing, and you´re still not clear on how
Kanban works, Im sure the next image will make everything fall into place! One
image is indeed worth a thousand words as they say!
