The Kanban method uses Kanbans or cards to signal work items’ status and monitor progress. This approach strongly relies on balancing production to demand, and maintaining an optimal flow. The nature of this method is such that it is very easy to use it to any industry. It also doesn’t have strictly defined roles, and it’s easy to modify it according to your organization’s process.
Through the years, Kanban has evolved to fit the needs of various industries. As a result, we now have different types of Kanban systems represented by the different cards, signaling the need to move items or replenish items in the work.
Kanban Cards and Kanban Systems
All Kanban systems use a Kanban board divided into three basic columns – To Do, In Progress and Done. Of course, when the process is more complex, the board can have additional columns and swim lanes. The key difference between Kanban systems are the types of Kanban cards each system is using. Just as the [production] process has different stages, we have different types of cards that resemble each stage. Each card has its own role in a specific segment of the production process and signals the proper actions that need to be taken.
Six Main Types of Kanban Systems
This type of Kanban is probably the most basic one. We see that type of card used everywhere, from manufacturing to software development. Production Kanban starts with a comprehensive list of all items that need to be completed at a specific time.
The work station provides a production card to an area in the facility requesting the types of materials (or tasks) they need. The production Kanban card signals the production system to start, explaining the quality and quantity of the things that need to be produced. Additionally, the production cards contain information included in the withdrawal of Kanban cards.
The withdrawal or conveyance Kanban system is concerned with the movement of items and components. Whether the company produces physical or digital products, different parts of it need work done by different teams in different areas. And when one team is finished, the ‘part’ is transferred to the next team and production area.
For that purpose, teams use withdrawal cards or movement cards to alert people that an item is finished and ready to move from one section to another. When the team is ready for more work, they send the withdrawal card to the previous section signaling they are ready for more work. Also, the card usually specifies the number of items that need to be taken to the workplace where they are needed.
The supplier Kanban card is an unusual type of Kanban that allows companies to include suppliers as part of the system. That way, the supplier cards go out of the organization and straight to the supplier, requesting a new batch of a specific item to be delivered.
The supplier cards streamline the process by cutting out the long wait times necessary for making a supply request. So, instead of sending a request to the procurement department and waiting for them to pass on the request, teams can communicate with the supplier directly and get the items and materials they need without further delays.
Emergency Kanban deals with an unexpected situation that needs immediate attention. Emergency cards usually signal the need for replacement of a faulty or defective part or a sudden change in the quantity of input (product) required.
This card is most commonly used when a problem with a part or series of parts is discovered to signal the team that was previously working on the items what kind of problem exists, so they can make sure the rest of the items don’t have the same issue. If the problem is serious, the emergency card can even signal the whole team to stop working so they don’t create a backup while the team dealing with the problematic items can address the issue. That way, teams won’t generate waste, and the production will keep running smoothly.
Similarly to emergency Kanban, the express Kanban system also deals with situations that must be resolved immediately. But unlike emergency cards which signal problems and defects, express Kanban cards signal the shortage of a specific item.
Teams can send emergency cards if their supplies run (very) low and might even that production needs to slow down. In extreme cases, emergency cards might even require that production stop completely until specified items or parts are delivered. Like the emergency cards, express cards are also important for maintaining a constant process flow, and ensuring there is no slowing down, nor stopping the process.
The through Kanban system and Kanban cards are a combination between production and withdrawal Kanban in situations where two different production teams that work together are also physically close to each other.
That way, instead of having the teams pass two different cards between each other, one to signal the start of work, and the second that the next team is ready to receive more work, the teams would use one though card to signal both of there actions, accordingly. This saves time and makes work more efficient.
Similarly to picking the way you implement Kanban – using a 2 bin system, CONWIP Kanban, time-based Kanban, etc., you can also pick the different types of cards you will use and build your system. These different Kanban systems can be combined and used together to achieve an organized production environment. You can pick two types or all six. You can color-code different cards types, put them in separate swim lanes… There are no set rules. Very often though, it is necessary to use all Kanban systems to ensure timely signalization, clear communication and optimal use of resources. Especially if your goal is to deliver a product to your customers.
Of course, select the Kanban systems that work best for you and make modifications according to your needs. Gradually introduce changes to your process or your existing system, and see what works best. After all, one of Kanban’s main goals is to improve the flow by introducing evolutionary changes.
So go ahead, start making changes today!