Which Model is Best for Your Facility, Six Sigma, Kaizen or Lean?
Do you have questions about the leading methods for improving factory productivity, quality, and efficiency — Kaizen, Lean Manufacturing, Six Sigma or Lean Six Sigma? We take a look at how each of these models came to be, which principles they use to solve problems, and which ones are best suited for your factory operations.
Steam Engine Turbine Blades. Image courtesy Siemens Germany / Christian Kuhna
The sheer volume and variety of high-quality consumer and industrial products we enjoy every day — produced by today’s state-of-the-art manufacturing facilities — would come as a complete shock to the industrialists, engineers, product designers and factory workers of the early post-World War II era.
Yet the backbone of today’s best practices in manufacturing — from just-in-time manufacturing methods, long supply chains, and sophisticated quality control programs — can clearly trace their roots back to this period when Japanese industrial engineers began to incorporate American research on statistical quality control into their own factory production methods.
This fusion of Japanese and American production philosophies that began more than 70 years ago has been the basis for the different framework methodologies used by leading production facilities today, including:
- Kaizen / Toyota Production System: the just-in-time production system pioneered in Japan
- Lean Manufacturing / The Toyota Way: a further evolution of Kaizen as a global production system
- Six Sigma: a process improvement model introduced in 1996 by Motorola (and later widely promoted by General Electric’s CEO Jack Welch)
- Lean Six Sigma: an organizational model that combines the best features of Lean Manufacturing and Six Sigma
As we look at each of these different models, it’s important to understand the chronological history and the extent to which each model has been influenced by the others — including cases (such as Six Sigma) where they have adopted major components from other models.
The Kaizen Model and the Early Versions of the Toyota Production System
Many credit Toyota’s rise from a sophisticated pre-WWII textile company to one of the world’s pre-eminent manufacturers of automobiles to their adoption of a rigorous, scientific approach to making continuous incremental improvements (‘Kaizen’ means improvement in Japanese).
Image by tradefax.net
Japanese engineers, including Toyota’s Taiichi Ohno, the father of the Kaizen philosophy (where it is known internally as the Toyota Production System or TPS) were highly influenced by American manufacturing pioneers, including Frederick Winslow Taylor (for his scientific timing studies of industrial production methods), Henry Ford (for embracing interchangeable parts and Design for Manufacture, or DFM, methods to reduce waste) as well as W. Edwards Deming (for his research into statistically-based quality control methods and the promotion of Shewhart’s Plan-Do-Study-Act or PDSA cycle.)
There are many different organizational tools and techniques used in the Kaizen method to incrementally reduce waste and improve efficiency, ranging from the principle that any factory worker who encounters a defect can pull a cord to stop the production line, to a type of root cause analysis method known as the 5 Why’s, to the systematic, multi-stage 5S approach which helps factories improve material flow while reducing overall inventory storage requirements.
Some people also refer to Kaizen in the context of what is called a Kaizen Event (or Kaizen Blitz or Burst) that is used to solve a particular production problem during a short, intense period of time.
Finally, the influence of the Kaizen approach extends to many other major frameworks in use today — including Kaizen’s direct successor (Lean Manufacturing), an alternate framework known as Six Sigma, and the combination of both of these models, known as Lean Six Sigma — all of which incorporate the Kaizen approach as a foundational principle in their models.
The Lean Manufacturing Model, Successor to the Kaizen Model
Even though the Kaizen model was widely responsible for major improvements in the quality of Japanese manufactured products, it stayed off the radar of American manufacturing engineers and management teams for decades. This changed quickly in the late 1970s and early 1980s when the number of Japanese imports, particularly automobiles, reached a tipping point as an increasing number of American consumers elected to buy high-quality, ultra-reliable cars from Toyota, Mazda, Nissan and Subaru in lieu of Detroit’s Big Three offerings.
Suddenly the American economy faced a widely-publicized crisis as “Japan, Inc.” threatened to drive the big-three American car companies out of business. (At the time Chrysler was saved thanks to a controversial 1979 government loan.) In 1981, the Reagan administration hastily negotiated a “Voluntary Export Agreement” with the Japanese manufacturers that limited Japanese car imports into the USA to 1.68 million vehicles.
Thanks to the law of unintended consequences, this quota (which only covered vehicles actually made in Japan) led Japanese car makers overcome it by investing in the construction of brand new American “transplant” factories, including a unique joint venture, New United Motor Manufacturing, Inc (NUMMI), between Toyota and General Motors.
It’s generally agreed that GM, despite being a co-owner of a successful new factory with its arch-rival Toyota, was slow off the mark to learn and apply the “secrets” of Japanese manufacturing successes, which were based on Kaizen/Toyota Production System methods outlined above.
Adding insult to injury, the NUMMI factory, located near Silicon Valley in Fremont, California, had to be liquidated in 2010 during GM’s bankruptcy. Today it stands re-opened as the Tesla Motors electric car factory, which poses fresh challenges to the reconstituted GM.
The startling success of Toyota’s American transplant factories (and those of other Japanese manufacturers, such as Honda in Marysville, Ohio) in producing high-quality cars in America using American labor undercut the then commonly-held belief that Japanese workers were somehow inherently superior to their American counterparts. Instead, it became increasingly clear to the American public that something else was responsible for Japanese success. The answer seemed to lie in the sophisticated Kaizen factory management principles used by the Japanese companies.
The Kaizen model becomes widely known in North America as Lean Manufacturing.
The term Lean Manufacturing was first used by John Krafcik in his 1988 article titled “The Triumph of the Lean Production System.” It was followed by a best-selling book called “The Machine That Changed the World.” Soon the term Lean Manufacturing had completely eclipsed the lesser known Kaizen term as the preferred way to describe efficient Japanese production methods in America.
Image by Wikipedia
Meanwhile, as Toyota opened new production facilities around the world, it needed to revise its own Kaizen-based systems into order to indoctrinate new teams of workers who had never had any exposure to the Toyota Production System. Today, much of Toyota’s lean manufacturing effort go into mentoring its diverse workforce to feel respected and empowered enough to identify problems and improve its products and processes. Toyota refers to its own evolving Kaizen-based approach as The Toyota Way.
