Muda, Mura and Muri
Contents |
Idea
Muda, Mura and Muri is a concept developed by car manufacturer Toyota and is referred to as the 3 M's of waste in lean manufacturing. They collectively describe the practices companies can eliminate of to reduce non-value adding use of resources. These three waste types can be found in both manufacturing and office processes.
Muda
Muda is the Japanese word for "waste" and relates to any activity or practice that does not in any way produce value for the customer. There are, as explained by the so-called "father of the Toyota production system", Taiichi Ohno, 8 categories of waste. Simply eliminating Muda will not be of help to the company without finding the reason for the waste, which will usually correlate with the two other wasteful practices; Mura and Muri.
The eight categories of waste:
- Transportation
- Inventory
- Motion
- Waiting
- Over-processing
- Over-production
- Defects and Rework
Mura
Mura presents the wastes of unevenness or inconsistency and often occurs in linkage with inconsistency in customer demand, cycle times variation and an uneven work pace. The waste of unevenness can often be eliminated by creating and encouraging openness in the supply chain
Muri
Links to the waste of overburden by causing unnecessary stress and strain to employees or equipment. Muri can transpire as a result of lack of training, limited focus on safety and non-successful measures of performance.
Application
The three M's in lean manufacturing, Muda, Mura and Muri are often analogous and to eliminate one often means that the others is eliminated simultaneously. By applying various tools such as Kanban, Just in time (JIT) etc. it can strengthen production stream, assisting to reduce Mura, the waste of unevenness. The Trusted Platform Value (TPV) and the 5S methodology are frameworks that can be applied to eliminate the waste of overburden, Muri.
