Four basic principles of Kanban
1. to get the idea about the process – this means you first understand the process that is existing. Kanban doesn’t say to change the current process without knowing it.
2. Agree to small changes – this means that whenever there is a small change due to Kanban, support it. The reason is, Kanban is a tool that clears problem or guide you to the success through small changes rather than abrupt changes.
3. Respect the current scenario – When one implements Kanban in the current process, it does not tell you to change the whole process, but to make the small changes in the current process which does not add value to the process. And it does not tell you to change the steps that adds value to the process. So, one must respect the current process, roles and responsibilities of the whole system.
4. Encourage all – Since it is a tool of improvement and it involves all, ideas must flow from all directions and they must be respected. Ideas can come from any of the team members rather than just the management team.
Six general practices of kanban
1. Visualize the work flow
· Break down every step from beginning to the end of the process and create a column or line(lane) for each step.
· Write down tasks separately on a physical card.
· Differentiate the types of tasks for easier visualization with the help of the colour codes.
· Work flows from left to do to right done as shown in figure below.
2. Limit the work flow
· Do not do such task which cause harm to your process efficiency at a single time. There needs to be a limit, where only a particular task needs to be done to reduce waste and improve the efficiency.
· Put limits on columns in which work is being performed.
· The goal of WIP limits are smooth workflow and waste elimination.
3. Manage Flow
· Improvement should always be based on measurements, so find and apply methods.
· Use the gathered data to adjust your process to maximize flow and efficiency.
Using these steps, you will be able to identify where your tasks needs to be adjusted, and what works best for you and your team.
4. Make policies explicit
· The team must form the basic rules on the flow of different items, when and how to note.
· This needs to be marked on the board.
· For the continuous improvement, meetings must be carried out weekly or at the end of the shift to check whether work flow is going as per the flow or not.
· Feedback is necessary as it will indicate if anything needs the improvement or is going well.
6. Collaborate for improvement
· It requires the involvement of all departments, rather than just one.
· It is a team effort.
Rules of kanban by Toyota production system
Ø There are 6 rules defined by the Toyota production system: –
1. Downstream processes withdraw the items in the exact amount mentioned by Kanban.
2. Upstream produces items in precise amounts and sequences given by Kanban.
3. No items should be moved or produced without kanban.
4. Kanban cards must accompany each and every time with the parts.
5. Defects and incorrect amounts should never be sent to the next downstream process.
6. The number of Kanban cards is reduced carefully to minimize inventory and find the problems.
Types of kanban cards
Ø There are two principal types of Kanban cards:
1. Withdrawal Kanban
· Withdrawal kanbans also known as “move cards” are used to signal when a part is ready to move from one lane to another lane in the manufacturing areas. The card is attached with a prescribed number of parts, which are moved to the work area that needs them. Once the parts are used, the card is returned as a signal to send the same number of the same part back. An example of withdrawal Kanban card is shown in figure
2. Production Kanban
· A kanban that contains a comprehensive list of everything the part requires in order to be completed is called the production kanban. This includes the parts required, the materials required and the information included on a withdrawal kanban. Importantly, a production kanban orders the production system to start with the production of parts required in the production area. An example of production Kanban card is shown in figure
Ø In addition, other types of Kanban cards that exists are:
3. Express Kanban
· Express kanbans come into use when unexpected shortages of parts occur, to indicate the need for more of a particular part or material so that the manufacturing process does not get stopped and work flows smoothly. These are also sometimes known as signal kanbans. Essentially, they are used to trigger purchases.
4. Emergency Kanban
· Emergency kanbans are used to replace the defective parts or to signal a sudden change in the amount of product that are needed to be produced. Unlike express kanbans, emergency kanbans are utilized when a part does not function like it is supposed to or when the conditions of production changes.
5. Through Kanban
· It is a combination of withdrawal and production kanbans, and are used when the two work areas for these kanbans are located close to each other, in order to speed up production. For instance, if the storage area for components is right next to the place where the product is assembled, having a single kanban to pull the parts and run them through the production process saves time.
6. Supplier Kanban
A supplier kanban is for the supplier – that sells materials to the manufacturer and enters the supplier’s kanban system as a representative of the manufacturer. They receive the card with the number of parts or raw material required by the manufacturer.