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| Lean and Six SigmaMarch 31, 2004 Many
of today’s articles, books, and seminars are focusing on the power of
combining Lean and Six Sigma. Most
of these take a Six Sigma perspective; that is, they talk about adding lean
tools to a Six Sigma program to make the program more effective.
I believe such an approach can work; however, I believe that lean should
drive six sigma initiatives.
Furthermore, I believe that the tools of Six Sigma can be effectively
integrated into Lean without actually implementing a “Six Sigma” program.
While this might be considered sacrilege to the Six Sigma faithful, there
are facts to support this assertion. Firstly,
let us consider Toyota. The first
word that people might think of when they think of Toyota is “Quality.”
Toyota’s vehicles are consistently rated among the most reliable;
customer satisfaction is consistently very high. Yet, Toyota does not have a Six Sigma program in place.
They use the Toyota Production System, or, as it is most commonly called
in the rest of the world, “Lean Manufacturing.”
Looking beyond Toyota, James Womack and Daniel Jones in the book Lean
Thinking performed a study on 50 companies that have implemented Lean. After an initial lean conversion, the companies averaged a
50% reduction in errors reaching customers and a 50% reduction in scrap rate-
all without a single black belt! How
can this be done? A
lean program focuses on eliminating non-value-creating activities or waste.
Value Stream Mapping is a powerful lean tool that identifies waste and
sources of waste. Many times, Value
Stream Mapping uncovers problems that cannot be solved without reducing process
variability. Process variability is
the reason for many of the seven wastes; for example, it can be responsible for
overproduction, excess inventory, defects, overprocessing, etc.
In come cases, process variability cannot be reduced with a simple fix
such as a go/no-go fixture; the tools of Six Sigma (which have been around for
years) and the Six Sigma DMAIC methodology are very effective in these cases.
This is where Six Sigma fits into lean.
The Black Belt/Green Belt system can work very effectively, but it
isn’t required for using the tools of Six Sigma. Let’s
take an example. “B” Company produces machined components and assembles
them into widgets. “B” company
has 4 manufacturing processes within its operation: Machine 1, Machine 2, Weld,
and Assemble. After mapping its
value streams and creating a future state map, “B” company discovers that it
must make the following four improvements to achieve its future state: 1.
Increase Weld uptime (by implementing TPM, Total Productive Maintenance). 3. Reduce
the scrap rate on machines 1 and 2. 4.
Eliminate the rework portion of its assembly activity. “B” company might find that it needs to apply the tools of Six Sigma to achieve the third and fourth improvements. It can do this in a variety of ways. If it has a true Six Sigma program in place, it can create two projects and assign a black belt and a team to each using the DMAIC methodology. If it doesn’t have a formal program in place, it can have a team perform exactly the same function as a Six Sigma team; they can also use DMAIC. Alternatively, they can assign an engineer to solve the problem using the very same tools; he may need to form a team, or, if the problem is not quite that complex, he may be able to solve it on his own with some input from others. As long as the problem is solved and the above initiatives can be implemented, success will have been achieved. Some
companies view Six Sigma as their prevailing, culture-changing program and add
lean tools to their Six Sigma toolbox. Others
have lean as their program of emphasis with six sigma tools as complimentary.
I've seen successes on both sides; however, I believe that Lean is the
most effective methodology when used by itself (while making use of the
statistical methods and problem solving tools of six sigma).
Many companies that have implemented lean (such as Toyota) have superb
quality without having implementing Six Sigma specifically.
However, it should be noted that these companies do apply the statistical
methods of Six Sigma to improve their processes.
This has been going on long before the term "Six Sigma" as a
program was ever used. Click here to subscribe to our free e-newsletter Learning to Lean and receive three articles like this one each month. About the Author Darren Dolcemascolo is an internationally recognized lecturer, author, and consultant. As Sr. Partner and co-founder of EMS Consulting Group, he specializes in productivity and quality improvement through lean manufacturing. Mr. Dolcemascolo has written the book Improving the Extended Value Stream: Lean for the Entire Supply Chain, published by Productivity Press in 2006. He has also been published in several manufacturing publications and has spoken at such venues as the Lean Management Solutions Conference, Outsourcing World Summit, Biophex, APICS, and ASQ. He has a BS in Industrial Engineering from Columbia University and an MBA with Graduate Honors from San Diego State University. | |||||||||||||||||
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