When Lean Meets Six Sigma

Trends come and trends go, but being lean is always in fashion. And so it is with Lean Manufacturing, which, in its most classic definition, is the elimination of waste and all non-value added activities from the manufacturing process.

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While Lean Manufacturing has been in vogue for some years, an emerging area is the combination of Lean Manufacturing techniques with Six Sigma metrics and strategies. So hot is this trend, it was standing room only in the “Integration of Lean and Six Sigma” conference session, held as part of the 2004 International Manufacturing Technology Show (IMTS) conference, and sponsored by the Society of Manufacturing Engineers (SME).

Presenters Michael Bremer, of The Cumberland Group, in Hinsdale, Ill., and Tom McCarty, of Motorola University, in Schaumburg, Ill., led participants in a two-hour overview of Lean and Six Sigma methodologies, followed by a one-hour, hands-on workshop in which principles were applied in real time.

Hammer or screwdriver

I asked Bremer to clarify the differences between Lean and Six Sigma, and how manufacturers should apply these strategies. “Some people ask ‘Lean or Six Sigma?’ That is not the right question. Is a hammer better than a screwdriver? It depends on the application. The same is true with business improvement methodologies. They all have their benefits,” explains Bremer. “Lean methods tend to focus on speed and eliminating waste, while Six Sigma is an outstanding process for solving difficult problems and finding answers that are not easy to see. As a management system, Six Sigma brings a rigorous measurement analysis that is missing in most process improvement efforts. It is used to probe, dig deeply and identify the root cause of a problem.”

According to Bremer, the primary benefit of Lean is to free up capacity, whereas the primary benefit of Six Sigma is to eliminate variability. Of course, the main benefits of Lean methods will translate into actual savings only if the manufacturer is in a growth mode and has a need for more capacity.

A better PLM

Applying Lean and Six Sigma to the Product Lifecycle Management (PLM) process can pay extra dividends. The combined methodologies do two great things—they force product designers to meet real customer requirements and they ensure that manufacturers make product in the most cost-effective way. “The way we’re doing it in the Motorola world—we bring together a team of people and go through a definition of customer requirements and prioritize the key areas.” The team uses Six Sigma tools to provide a very specific starting point for product design.

“As you move into the process portion of PLM,” continues Bremer, “you get into an area where Lean plays a role by eliminating unneeded steps and transactions. If you’re growing, then you can fill that time by making product you can sell.

“After the product has peaked and you reach the down cycle of the product’s life, you can still get benefits from Lean, but it’s not as easy,” he says. “If you have nothing to make with the added capacity, then you haven’t achieved a financial benefit. If you’re only producing a product that goes into inventory, or if the manufacturing line sits idle, then you have no real savings.”

At this point in the product lifecycle, Six Sigma statistical tools can be used to eliminate any variation in the manufacturing process and squeeze the last dollar out of the product lifecycle. Then, it’s back to the drawing board, applying the Six Sigma management strategy to determine the next-generation of products to meet customers’ needs.

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