Kanban is an efficient replenishment system for inventory or work in process. Once this is set up it can run for itself with little intervention if followed correctly. The simplest form of Kanban is an “empty space”.
An example would be the dispenser at convenient stores when you pull a beverage from the refrigerator gravity lets the next one fall into place. On the backside of that row there is now a gap that tells the operator to add another beverage. Because of that physical space the operator cannot place too many drinks nor can the system run out of drinks, as long as the process is followed.
This can be used and modified to work in most manufacturing situations. Most of the time it is used for line management to maintain proper inventory levels to keep production moving without the need for intervention and it is the way to achieve JIT (just-in-time manufacturing).
How does kanban work? First, it helps visualize workflow. Creating a workflow model to help further understand the environment is crucial to creating an effective kanban system. Also, walking the flow and going out to the shop floor is a must do. Just knowing the process is one aspect, but physically being there and watching material move will give the best representation of what is needed.
Second, kanban limits WIP (work in process), which lowers the amount of time it takes for material or items to move through the kanban process. Task switching complications are then lowered because priorities are easier to set and reorganize if need be.
Third, is the focus on flow by using WIP limits and team driven policies. This gives the factory an ability to manipulate the system if need be to increase or lower WIP numbers.
Finally, kanban creates a push for continuous improvement. With an effective kanban system teams can track flow, throughput, and lead times. Once those metrics are identified, it makes the process of manipulating them for the factory’s benefit more agile.