A fusion of Japanese and
US management principles focusing on the reduction of: waste,
inventory and customer response time.
John Krafcik, an
Massachusetts Institute of Technology (MIT) researcher in the
late-1980s coined the term Lean Manufacturing. He had been involved
in a study into best practice in automobile manufacture. The MIT
study had examined the methodology developed at Japanese auto giant
Toyota under the direction of production engineer Taichi Ohno. At
the end of World War II with Toyota needing to improve brand image
and market share, Ohno reputedly turned to Henry Ford’s classic
book, “Today and Tomorrow” for inspiration. One of
Ford’s guiding principles had been the elimination of waste
(The Japanese word for waste is muda). Ohno identified seven
wastes (“the 7Ws”): Defects, Over-Production,
Waiting, Transporting, Movement, Inappropriate Processing and
- The simplest form of
waste is components or products that do not meet the specification.
The key point came with the switch from Quality Control to Quality
Assurance - efforts devoted to getting the process right, rather
than inspecting the results.
- A key element
of JIT was making only the quantity required of any component or
product. Another Toyoto engineer who contributed to this change was
Shigeo Shingo who led the move long machine tool set-ups to “Single
Minute Exchange of Die” (SMED).
- Time not being used
effectively is a waste. Ohno looked at the reasons for machines or
operators being under-utilised and set about addressing them all.
- Items being moved unnecessarily incur a cost.
- People moving unnecessarily also incur a cost.
- Inappropriate Processing
- A basic principle of the TPS is doing only what is appropriate.
- Ohno was also
influenced by the way shoppers in the USA were then beginning to
purchase products from supermarket shelves, using a “take
what’s needed, when it’s needed” approach. His
response to this observation became known in the West as Just in
Womack and Jones, the
leaders of the MIT Study, suggested an 8th waste:
“designing and making products, which do not meet the
customer's requirements”, though this could perhaps be
classified within Ohno's Inappropriate Processing.