Lean manufacturing fundamentals

Define value from the customer's point of view, map the value stream, create flow, establish pull, and seek perfection. Defining value comes first because it sets the foundation for everything that follows.

Defects, overproduction, waiting, non-utilized talent, transportation, inventory, motion and excess processing, remembered by the acronym DOWNTIME. Taiichi Ohno identified the first seven in the Toyota Production System; non-utilized talent was added when Western manufacturers adopted lean.

Muda is waste, mura is unevenness and muri is overburden. In Toyota's 3M model they are linked: unevenness in demand or workload creates overburden on people and equipment, and overburden generates the eight wastes, so removing muda without fixing mura and muri gives only temporary results.

Lean targets waste, meaning any activity the customer would not pay for, while Six Sigma targets variation, the statistical inconsistency in a process's output. That difference shapes their tools, their certification structures and how quickly each tends to produce results.