Lean manufacturing

Lean manufacturing is a generic process management philosophy derived mostly from the Toyota Production System (TPS)[1] but also from other sources. It is renowned for its focus on reduction of theoriginal Toyota 'seven wastes' in order to improve overall customer value. Lean is often linked with Six Sigma because of that methodology's emphasis on reduction of process variation (or its conversesmoothness). Toyota's steady growth from a small player to the most valuable and the biggest car company in the world has focused attention upon how it has achieved this, making "Lean" a hot topic inmanagement science in the first decade of the 21st century.
For many, Lean is the set of TPS 'tools' that assist in the identification and steady elimination of waste (muda), the improvement ofquality, and production time and cost reduction. To solve the problem of waste, Lean Manufacturing has several 'tools' at its disposal. These include continuous process improvement (kaizen), the "5 Whys"and mistake-proofing (poka-yoke). In this way it can be seen as taking a very similar approach to other improvement methodologies.
There is a second approach to Lean Manufacturing which is promoted byToyota in which the focus is upon implementing the 'flow' or smoothness of work (opposite of mura, unevenness) through the system and not upon 'waste reduction' per se. Techniques to improve flowinclude production levelling, "pull" production (by means of kanban) and the Heijunka box.
The difference between these two approaches is not the goal but the prime approach to achieving it. Theimplementation of smooth flow exposes quality problems which always existed and thus waste reduction naturally happens as a consequence. The advantage claimed for this approach is that it naturally takes asystem-wide perspective whereas a 'waste' focus has this perspective assumed. Some Toyota staff have expressed some surprise at the 'tool' based approach as they see the tools as work-arounds made...