Comments on: Why Flow Counter Clockwise?

By: Let’s Create a Future State Value Stream Map! | Lean Six Sigma Academy

Sun, 03 Aug 2008 20:09:41 +0000

[...] the team worked with their lean sensei and designed a u-shaped cell where all 3 operators would work in a one piece flow manner. Once the work was redistributed the [...]

By: Calculating Optimal Crew Size in Mixed Model Cells | Lean Six Sigma Academy

Calculating Optimal Crew Size in Mixed Model Cells | Lean Six Sigma Academy — Wed, 14 May 2008 02:38:42 +0000

[...] Let’s assume, hypothetically speaking, we have developed a u-shaped cell were material flows counter-clockwise. [...]

By: Revisiting “Why Flow Counter Clockwise?” | Lean Six Sigma Academy

Fri, 29 Feb 2008 14:01:36 +0000

[...] I don’t normally do this, but I’d like to revisit a past article I wrote about why u-shaped cells often flow counter-clockwise. [...]

By: Bryan Lund

Bryan Lund — Fri, 29 Feb 2008 04:00:35 +0000

Another more practical reason may exist…but we must consider the origin of workcells at Toyota. It may be that when Ohno, or a supervisor, experimented with flow in his machine shop he encountered a problem never faced prior to workcells: all lathes have their headstocks on the left side of the machine requiring operators to load stock with their right hand and tighten the chuck with their left. In a workcell manufacturing to JIT; parts were unloaded – the left hand placing the finished part in the bin to the left while picking up the stock for the next cycle with his right. My guess this efficiency in loading materials, (until auto bar loaders and through spindles replaced a machinists hands) was proliferated throughout Toyota and its keiretsu of suppliers. Counterclockwise workflow was the countermeasure for eliminating extra fumbling of the part between hands during load/unload cycles.

Often something that is innocuous becomes conventional wisdom. I literally have seen and heard lean consultants state that workcells MUST go counterclockwise for the right hand reason. It is almost taboo to suggest anything but U-shaped and counterclockwise. But I think most people, except those posting comments here, dismiss the taboo attitude and forget to understand why counterclockwise exists in the first place. Since the workcell is the most copied lean concept born from TPS than it only makes sense that something so copied for so long has evolved into a sacred cow in North American lean literature and practice.

The fact that the majority of the population is righty and may be a convenient and viable reason for not trying to make our workcells flexible, but how to explain right hand people doing things with their left hands everyday? Rolling down the driver side windows, typing, opening door handles, tying their shoes, using utensils, or juggling? Don’t believe me? Give your toddler who is learning to use utensils – toddler SAFE utensils please – a knife and fork. Watch them struggle with their non-dominant hand. Then you do the same and marvel at how easily it seems to you, how you don’t even think about it. Try to think about it as you cut your steak, slice a cooked carrot with ease between the tines of your fork. You can’t even think about it as it comes so naturally, right? The fact is, people can LEARN to use their left hands as well as their right and vice versa – with practice and discipline.

Of course, I don’t think I can prove any of this, it is just an educated guess based on experience, but I think its a pretty good guess. What do you think?

By: Mark Graban

Mark Graban — Thu, 04 Oct 2007 03:36:40 +0000

Hi Ron – yes, I was taught the same things about counterclockwise and why that’s “correct.”

I also think that’s a rule that’s a good rule to follow unless it isn’t… as you were alluding to, I think there’s no substitute for thinking and for experimentation. That’s always better than blindly following rules.

By: Ron Pereira

Ron Pereira — Mon, 01 Oct 2007 01:38:53 +0000

Hi Brad,

Yes, I would say you are correct in your assumption. Thanks for the kind words as well. I will see what I can come up with on the management topic.

Hi Andy,

Thanks for the comment! I have followed your work for awhile and am honored you read my little blog. I didn’t know this about aircraft carriers. Thanks for sharing and commenting. Cheers.

By: Andy Wagner

Andy Wagner — Mon, 01 Oct 2007 01:18:36 +0000

Another example of counter-clockwise flow is an aircraft carrier. With one exception every aircraft carrier ever built has had a counter-clockwise landing pattern. The exception, a Japanese carrier, was built to operate with a counter-clockwise sister ship. The theory was that each carrier would have it own opposing landing pattern that would allow them to sail close together in formation.
As it happens, pilots tend to abort landings by veering to the left. On a clockwise carrier, the superstructure is on the left side instead of the right, which is where aborting aircraft tended to crash.
The ship was rebuilt before the war with the tower on the “right” side.

By: Brad Smith

Brad Smith — Sun, 30 Sep 2007 20:29:03 +0000

So I assume if you do happen to have a bunch of lefties clockwise movement may be best, right?

Thanks for this post. It was great. I am now a subsciber to your blog. Keep up the great work.

Also, I see you are a Director of Manufacturing. Any chance to get some management related posts?