Kanban System
Kanban is some type of a signalling system, the signalling system can be cards or containers to identify where materials are stored. Where the containers are empty, the cards or the container itself can be used as the indication for the operators to produce more products.
The number of kanban cards can be determined by using this formulae :
Demand*Lead time*(1+Safety Stock)
No of kanban cards= -------------------------------------------------
The number of units produced
To understand it further, consider the example below:
Gorge Pty Ltd, a company that makes different types of steel dies, is going to change its manufacturing system to a kanban pull system. One
of the parts required to produce a product 001 is part A and part As are made in batches of 20 units. The manufacturing cell which makes part
A can respond to an order for a batch of part A in 2 hours. The assembly cell which assembles product 001 has an assembly rate of 10 per hour. The production manager has decided to have 10% buffer in case there is a change in the number of demand for part A. Now it is necessary to determine the number of kanban card needed.
Solution:
The demand for part A is 10 units / hour
The number of unit produced is 20 units
The lead time to replenish part A is 2 hours
The buffer /safety stock is 10% of the expected demand
10*2*(1+2)
No of kanban card=------------------ = 3
20
Thus, we need four kanban card sets.
Note: in all cases, if the number of kanban card is not a whole number, that number has to be always rounded up as we need to work with full containers of parts.