IoP logo Kanban, or more properly Kanban Control, is a very simple approach used in a Just-In-Time system to ‘pull’ supplies of materials to a workstation as and when they are needed.  Kanban is the Japanese term for card or signal and initially kanban systems were all card-based, though they later took other forms.There are two essential types of kanban – the MOVE kanban and the PRODUCTION kanban.

Not surprisingly, the MOVE kanban is used to trigger a movement of materials, normally from inventory to a workstation.  The kanban would have recorded on it the details of the part in the container, its current position and its destination.  As a workstation uses up its current supply of the part, the operator sends the kanban to the supplying location and a fresh supply is provided.  This movement of parts cannot take place without the kanban being transported along with the parts.  This ensures that the workstation is never over-provided (with attendant untidiness and perhaps risk of accident).

The PRODUCTION kanban, again not surprisingly, is used to trigger the start of production of a batch of components.  The kanban would contain details of the component to be produced, a description of the process, details of any materials required (which might have their own MOVE kanban) and the location to which the components should be sent when finished.

Any batch of components should be accompanied by a kanban at all times.  A batch of parts waiting in inventory would have the PRODUCTION kanban from their production run.  When the MOVE kanban arrives to trigger their release to the next part of the process, it replaces the PRODUCTION kanban in the container and the PRODUCTION kanban goes back to the preceding workstation to trigger production of the next batch.

Kanban control is a very simple process of which the key elements are:

  • no movement or production can be started without the appropriate kanban (so a pallet of parts cannot be moved until the kanban arrives from the requesting workstation)
  •  movement or production is always triggered by the succeeding part of the process (they ‘pull’ goods towards them when they need them)
  •  all containers of the same kind of parts will have exactly the same number of parts

In true JIT and ‘lean’ style, there is also another imperative … over time there should be investigations undertaken to reduce the number of kanbans (i.e. to reduce inventory) and to reduce the time between kanban calls (by speeding up activity at workstations).

Back to Briefings