WHAT IS LEAN?

The TPS is often used interchangeably with the terms, Lean Manufacturing and Lean Production. Regarding the technical issues of TPS and Lean, I also, will frequently use these terms interchangeably. It is called Lean because in the end, the process can run:

  • using less manpower,
  • take less time,
  • consuming less space and
  • using less equipment investment.

But even more importantly, a Lean process, be it the TPS or another, is characterized by a flow and predictability which severely reduces the uncertainties and chaos of typical manufacturing plants. It is not only financially and physically Leaner; it is emotionally much Leaner than non-Lean facilities. People work with a greater confidence, with greater ease and with greater peace than the typical chaotic; reactionary, change-the-plan-hourly-and-then-still-work overtime-and-then still-expedite, manufacturing facility.

Lean and the Toyota Production System

To further explore the depth of what a Lean Manufacturing system really is, we will look deeply at the TPS. Not because the TPS is the best Lean system around, although it may be. I can say it is the best I have seen. Rather we will look at the TPS because it is the best documented system and it has proven itself over a very long time. It has not only proven itself but it stands as the example of “Lean done extremely well”.

WHAT DID OHNO SAY ABOUT THE TOYOTA PRODUCTION SYSTEM?

If we really want to understand what the TPS is, we certainly must listen to what the creator has to say. In any discussion about the TPS, Ohno will be my arbiter. A great deal has been written about Lean and the TPS but some of it misses the point. If there is any question about what Lean or the TPS is, we will use Ohno’s thoughts as the final word on the topic. His most notable writing on the subject is his book, The Toyota Production System, Beyond Large-Scale Production. In this book, Ohno made three key statements , which when taken together, define his TPS.

  • “The basis of the Toyota Production system is the absolute elimination of waste’ (pg 4)
  • “Cost reduction is the goal” (pg 8)
  • “After World War II, our main concern was how to produce high quality goods. After 1955, however, the question became how to make the exact quantity needed.” (pg 33)

Taken together we could then write a definition such as, “the TPS is a production system which is a quantity control system, based on a foundation of quality, whose goal is cost reductions and the means to reduce cost is the absolute elimination of waste”.

THE TPS AND HENCE LEAN MANUFACTURING DEFINED

I find all of these definitions to miss part of the essence of Lean Manufacturing. I do not think Ohno defined it more carefully because oftentimes we do not feel the need to define those things which are very near and very obvious to us. I believe others may not define it better because they simply miss the point and yet others may understand it but are not able to articulate it. My definition of the TPS is:

A manufacturing system which:

  1. has a focus of quantity control to reduce cost by eliminating waste and
  2. is built on a strong foundation of process and product quality,
  3. is fully integrated,
  4. continually evolving and
  5. perpetuated by a strong, healthy culture that is managed:
  6. Consciously,
  7. Continuously and
  8. Consistently.