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What is Kanban in Lean Manufacturing?

Kanban

When it comes to Lean manufacturing, efficiency is crucial. One method that is truly revolutionising the production process is the Kanban system, often visualised as a Kanban board.

What is Kanban?

Kanban is a Japanese term that combines the words “map” and “signal.” It acts as a guiding map or signal for various parts associated with production. More specifically, Kanban signals a need – indicating what part of a product or service should be produced, when it is needed, and who should receive it.

The Kanban map is also referred to as a stock or supply map. When the stock at a workstation is depleted, it signals the need to produce a predetermined quantity at the supplier or the previous process step.

There are different types of Kanban signals designed for various needs:

  • Empty Box: A visual hint for replenishment.
  • Lamp: An illuminated signal indicating a requirement in production.
  • Computer Message: An electronic signal for real-time updates.
  • Physical Card: An information card for staff.
  • E-Kanban Systems: Electronic signals for digital workflows.

Understanding Downstream and Upstream Processes

In a production line, downstream processes are the components where the product is either consumed or further processed. In a Kanban system, the “downstream processes” remove products from the upstream processes.

Upstream processes refer to the beginning stages of production, where production occurs in response to downstream demand. The upstream process produces the exact quantity of products specified by the Kanban signal. Without a Kanban signal, production does not occur. The Kanban signal always accompanies the material. If there is material without a Kanban signal, or a Kanban signal without material, it indicates a problem that needs attention.

Key Variations of Kanban

Several variations of Kanban cater to different aspects of production management:

  • One Map Kanban
  • 2-Bin Kanban
  • Transport Kanban
  • Production Kanban
  • Vendor Kanban
  • Signal Kanban
  • Kanban Board

One Map Kanban

The simplest Kanban systems are the so-called ONE MAP KANBAN systems. These systems visualise production signals via maps or containers, and the “supermarket” is close to the consumer. There are different types of one map Kanban systems, such as a physical card that specifies what must be produced, in what quantity, and for which workstations, including code numbers and other details. This type of Kanban is ideal for processes where different modules can be used to create an end product. The card can be used for one piece, one batch, or multiple batches.

2-Bin Kanban

Also called the “double pot” system:

  • Bin 1 contains the work stock used for production. This bin also includes a physical Kanban card.
  • Bin 2 contains a backup stock and another physical Kanban card.

When the first bin is empty, you take the Kanban card from it and give it to the responsible person for restocking. The second bin, holding your backup stock, is now in use. Once bin 1 is refilled, the system is back in balance. When bin 2 is empty, you take its Kanban card and give it to the responsible person to restock. The cycle then starts all over again. This method ensures you are never out of stock.

Transport Kanban (Conveyance Kanban/Withdrawal)

This Kanban acts as a signal to a previous process that materials can be taken from stock and transported to the next point. An example is the “two bin” system. Such a Kanban includes information like: ID, source, destination, and quantity.

Production Kanban

This Kanban signals that production can begin. It typically includes information about the processes, required materials, ID, and location where the produced goods must go.

Vendor Kanban

Similar to the transport Kanban, but used with external suppliers.

Signal Kanban

This Kanban is used to trigger production when a minimum stock level has been reached.

Kanban Board

A Kanban board is a visual tool that helps teams manage workflows and optimise processes. It typically consists of columns representing different stages of a process, with cards or sticky notes representing tasks or work items. By moving these cards across the columns, teams can track the progress of tasks from start to finish. Most Kanban boards include columns such as “To Do,” “Doing,” and “Done.”

Choosing the Right Kanban

Choosing the right type of Kanban depends on the specific requirements of your process. Whether it’s for transport or production initiation, the principle remains the same: receiving a Kanban signal triggers the transport, production, or stocking/re-stocking of something.

Which type of Kanban do you use? Whether it’s a 2-Bin system, Transport, Production, Vendor, or Signal Kanban, the main idea remains consistent – signals drive the workflow, making scheduling and organisation seamless.

Conclusion

In conclusion, Kanban is more than just a system; it represents a new way of thinking. This approach allows the work process to be kept under control, ensuring systems are smart and efficient. Companies can reduce waste and increase productivity overall.

Whether in manufacturing or service organisations, adopting Kanban can lead to significant improvements in workflow management, efficiency, and collaboration. Embrace the Kanban methodology to keep your processes streamlined and your teams productive.

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