Lean

The Toyota Production System, TPS, or Lean Manufacturing

During the tough years of post-war Japan, Toyota leaders rejected the Frederick Taylor's principles of Scientific Management and designed production lines to reduce wasted time and resources: the "Toyota Production System" (TPS) was the outcome. TPS process-improvement techniques are radically different from those chosen by Motorola for Six Sigma.


The search for continuous flow
The key progress idea of TPS is "continuous flow:" it implies that work units moving through a process should never stop; this avoids creation of static work in process, raw-materials and finished-goods inventory. The "father" of the method, Taiichi Ohno, outraged at the level of stocks found in post-war, US automobile factories, drew stocks on his "Value-Stream Maps" as tombstones to signify "dead" cash! He launched the idea of making only what the customer wants, in the quantity required and only when he needs it. Management at Toyota leads a relentless war on waste, requiring operations to maintain continuous flow in an environment without the "safety" of work in process to fall back on.

Certain very successful automotive corporations have used TPS techniques to rotate their entire corporate inventory every 90 minutes, far from the 200 days of inventory rotation common in some high margin process industries!

Making errors impossible to commit
Reducing inventory and work in process to get continuous flow needs a lot of thought to be given to avoiding displeasing customers through outages; as a result, operating managers use special techniques to create a mistake-proof environment; Toyota's mistake-proofing , called "Poka-Yoke," is associated with stable production using "Heijunka," and with carefully standardised tasks using "Jidoka" to limit variation.

Training is a key enabler in the TPS learning organisation; Toyota expects all its professionals to have detailed work knowledge and a keen sense of duty. Training is given by "Sensei," a corps of experienced, older executives responsible for transferring corporate knowledge, values and methods to new employees.

A keen sense of duty
TPS is as much based on the quality of human behaviour as on pure task management: both management and employees are expected to unite in a common obsession to destroy waste. In essence the TPS culture revolves around:

Owing to its cultural and human dimensions, this approach can be long and complex to implement, and the Toyota Production System has been adapted to Western cultures under the different name of "Lean Manufacturing."

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