Friday, March 05, 2010

Best Kanban Signal of All

There are many types of kanban. A kanban could be cards, bins, containers, trays, carts, spots on the floor, golf balls, ping pong balls just to name a few. What’s the best kanban signal?

First, what is a kanban? A kanban is simply a signal used to authorize production in a production system. Any method of signal works can work well if we are disciplined to follow and maintain the system. A kanban is typically tied directly to the physical parts making it easier to keep in synch with demand. As parts are pulled for consumption, this signal is sent to the supplying workstation or source as authorization to make more parts to replace the ones used.

However, before we automatically jump to using any kanban system just because we believe it is the “lean” thing to do, is there a specific problem or need in the first place? This is one of the most common mistakes made on the lean journey. We see a lean technique and rush to put it in use everywhere we possibly can. It’s like holding a hammer and running around looking for nails to hit, soon everything starts looking like nails. We rarely take the time to really understand our problems or needs before we act.

What if we can produce products for our customers in one week while the customer delivery expectation is two weeks, would we set up a kanban system to replenish parts? No, just build to the actual customer order which is the best kanban signal of all.

In this example, there is no need for a typical kanban replenishment system at this time. But if our leadtime extends beyond our customers delivery expectation, we certainly have a need to set up a production system to satisfy our customer with the least amount of inventory. After gaining a better understanding of the problem, we might consider using a kanban system while we are working on reducing our production leadtime within our customer delivery expectation.


Jeff Hajek said...


You're preaching to the choir here! I've been saying for years that people need to think of kanban as a workaround when they can't establish flow. Perfect flow, like on an assembly line, doesn't need a kanban.

By the way, how are you liking the new job?


Mike Wroblewski said...

Hi Jeff,

Spot on. Many of us may forget to think flow first and jump to kanban as the lean tool needed. Kanban is a countermeasure not the ideal condition.

I'm having a blast in my new job. I have already worked with many great lean practitioners working on improving and sharing ways to make it flow.

Thanks for asking.


Anonymous said...

When you can't flow, you pull. And like you said, using kanbans to signal production (or to do something) isn't always the right lean tool to use. Having a good PFEP to determine what should be on pull (and triggered by kanban) is probably the best way to determine production my humble opinion.

Steve@ETAC said...


The real key is to manage your customer's inventory by way of a kanban. You negotiate the kanban size based on usage, lead-time and batch size and deliver 100% on time.

Great blog,