Kanban, Types of Kanban, Withdrawal Kanban, Production Kanban, Rules of Kanban,

Kanban

Kanban is a Japanese word that means "visual card“, the visual & physical signaling system that ties together the whole Lean Production system

• A simple card system
• The system works very simply by identifying the material to which it is attached
• Kanban is a system that visually indicates when production should start & stop

 There are two types of Kanban system

1. Withdrawal Kanban (signal to refill raw material)
2. Production Kanban (signal to start production)

• Visualize bottlenecks clearly in real-time
• Reduce Inventory
• Improve work flow
• Prevent Overproduction
• Improves responsiveness to changes in demand

Rules

1. Don’t send defectives to the subsequent process
2. The subsequent process comes to withdraw
3. Produce only the quantity withdrawn
4. Equalize the processes
5. Kanban is a means to fine tuning
6. Stabilize & rationalize the process

How Kanban Works

• A Kanban card is affixed to each container & stored
• When needs a replenishment, withdraws one, removes the Kanban card & posts in a clearly visible area, & moves the container to the workstation
• Posted Kanban is picked by a stock person who replenishes the stock
• All withdrawals & replenishment's controlled by Kanban (from vendors to finished-goods inventories)

The number of Kanban cards in use is an important variable

Calculating number of Kanban

Where, 

N = Total number of containers (1 card per container) 

D = Planned usage rate of using work center (e.g., minutes, days) 

T = Average waiting time for replenishment of parts plus average production time for a container of parts (e.g., minutes, days) 

X = Policy variable set by management that reflects possible inefficiency in the system (the closer to 0, the more efficient the system) 

C = Capacity of a standard container

Expected Benefits

• Improved Material Flow
• Reduced Inventory (or WIP)
• Reduced Freight Costs
• No Waiting