Identify Bottlenecks, Improve Flow, & Eliminate Waste with Kanban

Kanban is a Japanese lean manufacturing term that is associated with the flow of production in a workplace. Kanban is usually achieved by visualizing or attaching moving cards to each stage of the production process so that you can see how many units are in any one stage at a time and whether some stages are getting backed up while also identifying other stages which may be under-utilized.

Creating Kanban

While there is no one way to do a Kanban visualization, many use whiteboards divided into columns. Each column represents a stage of production. Let’s say you’re creating cars. This is a complicated production process in real life, but let’s simplify it by saying there are four sections: One that creates the body frame of the car, one that produces the interior, one that puts together engines, and another that creates and assembles wheels and tires. Each of these four columns is labeled and then divided into two sub-columns; one for items that are “currently being done” and another for items that are “done” in that stage and ready to move on to the next. Each of these columns is populated with sticky notes or cards that represent the amount of items in that stage currently.

Because Kanban dictates that you are trying to promote as close to perfect efficiency as possible, no product should move onto another area of production until its Kanban card is moved as well. It is worth noting that Kanban is also known as the “pull” method because the amount of items entering production initially should be pulled from customer orders (so that it matches exactly, instead of you guessing at demand and keeping extra, wasteful stock of materials and products on hand). In the same way, each stage of production or station pulls from the Kanban indicators of the stations before and after it.

Reading Your Results

Let’s say you notice on your chart that there are a lot of Kanban cards piling up in the column that represents car interiors and their production still in progress. This can signal a bottleneck in your operation and necessitate that you use your resources – such as workers and production space – differently. If car frame Kanban cards are piling up in the “done” column, you might benefit from taking some people off of frame creation and training them to work on car interiors. If space doesn’t allow for this, you could also change up the proportion of your assembly line or floor dedicated to each step.

What you’re basically trying to do with Kanban is balance out the process until you have each stage pulling out and producing the same amount of items and in the same amount of time as all of the other stages or stations. The close you can get to this perfect efficiency, the more profitable the time of you and your employees becomes.

Pull System and Kanban Demonstrated

Rules & Closing Thoughts

1. Someone on each team should be in charge of making sure that Kanban card representations and real items in production stay in sync and are accurately represented so that the results you observe are current and relevant.

2. When an item is defective it is never moved down the line, a new one must be produced – The Kanban attached to that item should be re-assigned to the new piece and moved accordingly.

3. The withdrawing and sending of items from one stage into the next can only happen as specified by the Kanbans associated with them – this ensures that the moving of items stays in line with the demand and possible bottlenecks of your production line.

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