Lean Manufacturing

Why So Much Confusion About Kanban?

By Jon Miller Published on March 28th, 2007

I had a very interesting conversation today with a friend who is a manager spearheading a Lean effort at a local facotry. His latest focus is on connecting the metal forming operations with the assembly operations using kanban. He observed that although there is a great need for kanban, there is so much confusion about kanban in the U.S.A.
Here is a short list of what kanban is not:
– A taped, painted, or otherwise marked storage location
– Two-bin systems
– Carts loaded with a specific number of parts and placed in a specific area
– Anything abbreviated IPK
– A faxed work order or P.O.
– Other methods for information transmission that end in -ban
– Just about any execution method promised by an ERP system
In the broad definition, the world calls nearly anything “kanban” that acts more like a pull than a push. If the result of kanban-like is less overproduction and more pull than push in this world, it may be OK. Then again, this leaves a lot of inventory and unimproved processes on the table.
I’m talking about the narrow definition of kanban. This is the system of cards developed by Taiichi Ohno to signal consumption downstream and order production upstream. The cards come in withdrawal, production, signal varieties with variants of these. The main purpose of kanban was to limit overproduction while linking processes that could not flow one-to-one.
Why is there no comprehensive, step-by-step book or instruction manual for kanban on the market, in English, yet plenty on kanban-lite? Does this reflect that there have been so few true kanban implementations from the ground-up in the United States? Or is it that only none of these have resulted in a book? Even in Japan, where better books and manuals on kanban are available, there are surprisingly few kanban systems implementation documents.
Kanban is not easy. Ohno said in his book that at one point he forbade the management in one Toyota factory from operating a kanban system with their supplier because the Toyota factory itself had neither an internal kanban system nor the discipline and systems this required for a kanban system.
Kanban requires being thorough with a lot of the basics such as 5S and not passing on defects. People must follow procedures to at least a quasi-Standard Work level. It also requires SMED and a certain degree of heijunka if lot sizes are to be kept small. Then there is the homework you need to do with container sizes, quantities, address system, delivery routes…
Perhaps it not so much confusion as being satisfied with kanban-lite or intimidated by the requirements of a full kanban system.

  1. Ralph Bernstein

    March 29, 2007 - 5:49 am

    Have you checked recently as to what’s available? At Productivity Press, we publish at least six kanban-related books and offer a DVD. And we have other books that touch on kanban. We know from experience our customers find them useful. I hope others will comment on what has worked for them.

  2. Jon Miller

    March 29, 2007 - 10:07 am

    Thanks for the alert Ralph. I just bought the the book on kanban you released in 2006.

  3. ricky

    March 29, 2007 - 8:18 pm

    very good

  4. Mark Graban

    March 30, 2007 - 6:52 pm

    I don’t think it’s true that there aren’t many kanban implementations out there. The “Kanban for the Shopfloor” book in the productivity press series is good as is the book “Making Materials Flow” from the LEI. You’re right, kanban isn’t that hard. If anything, companies implement kanban and not much else.
    Other than your friend, I’m not sure where the rant comes from.

  5. Jon Miller

    March 30, 2007 - 8:34 pm

    Add the word “lite” and I would agree with your experience.
    I said that kanban was hard.
    Take a poll on your blog. See what you learn.
    Making Materials Flow is perhaps the best book on in-plant logistics, though if memory serves, it teaches more of a foundation for kanban than the kanban system itself.
    Have you read Creating Level Pull by Art Smalley?

  6. Mark Graban

    March 31, 2007 - 6:50 am

    Maybe I’ll take a poll, I don’t think kanban is hard. The philosophy and management system is much harder to figure out than any of the tools.

  7. David Burton

    April 1, 2007 - 6:48 pm

    The whole conversation on Kanban systems is a very interesting one. Let me say off the bat I think Kanbans are extremely hard! The concept of pull is a simple one, but the process on how and what to implement is not that simple. I believe the ultimate goal of Kanbans is to eliminate overproduction and excess inventory, however, if the initial Kanban level is not set-up properly then a company could error on the side of having too much or too little inventory to buffer customer order fluctuations. Furthermore, the frequency of adjusting and resetting Kanban levels can become complex especially when dealing with seasonality issues. I have seen many companies get bogged down in the details when trying to create Kanban systems and never get off first base. To me you have to take a leap of faith (although somewhat calculated) and then be willing to adjust as you go along.

  8. ericmo

    April 5, 2007 - 12:43 am

    Kanban is simple yet could be difficult under certain circumstances.Production operators involved in the system should be well taught in the mechanism of kanban and the consequence it brings if not followed.Group leaders has the primary role of maintaining the smooth operation of kanban along with the audio-visual tools supporting this system.The group leader has to maintain discipline in the pick up and delivery operation/cycle of kanban.unless he does that will result to unbalanced flow of kanban consequently delay on some point.I’ve seen the TPS manual and were taught of it by Motomachi people and I would say its not that difficult. What Ive learned from experience is that control and familiarization are the first two things people should achieve first in order to have a successful kanban implementation.
    Its the material planners job to change the number of kanban based on monthly demand in a smooth and balance íncrease and decrease adjustment, and that i think is also fairly easy.
    Again i believe its control and familiarization that will be bring success.

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