What is Waste? Lean SIX Sigma

The elimination of waste is the primary goal of any lean system. In effect, lean declares war on waste – any waste. Waste or muda is anything that does not have value or does not add value. Waste is something the customer will not pay for. When the great Italian sculptor Michelangelo was asked what he was sculpting, he responded he was not sculpting but releasing the figure (value) inside by removing the unnecessary rocks (wastes). Like Michelangelo, we should eliminate all forms of wastes in any process or product until only what is valuable remains. The key is to spot waste and then stop waste. There are two types of wastes: obvious wastes and hidden wastes. It is important to uncover and eliminate the latter since they are usually bigger. Wastes take the shape of an iceberg, the tip consists of the obvious wastes while the seen bulk under the water contain the hidden wastes. Wastes are not necessarily ugly, and most are outside the waste can! Waste can be in the form of unnecessary output, input, or processing. It can be in the form of materials, stocks, equipment, facilities, manhours, utilities, documents, expenses, motion, and other activities that do not add value. The steps to effective waste elimination are: 1. Make waste visible. 2. Be conscious of the waste. 3. Be accountable for the waste. 4. Measure the waste. 5. Eliminate or reduce the waste In other words, before one can stop waste, he should able to see it, recognize it as waste, identify who is responsible, and finally appreciate its size and magnitude. Waste that is not seen cannot be eliminated. When something is denied as waste, it also cannot be stopped. When one refuses to accept responsibility for the waste, then he will not eliminate it. Finally, when the waste is not measured, people may think it is small or trivial and therefore will not be motivated to stop it. As the saying goes “What is not measured, is not improved”.
Muda, Mura, Muri

Aside from “muda” or wastes, the lean system also attacks and avoids “mura” or overload or overburden and “muri” or unevenness. Mura refers more specifically to overloading an equipment, facility, or human resource beyond its capacity. This undue stress may cause downtime, defects, delays, and even disasters. Muri refers to unevenness in production volume. The wild fluctuations due to extreme highs (peaks) and lows (valleys) in production scheduling cause periods of overload and long idle time. One way to reduce muri is to implement heijunka or production leveling. In a way, mura and muri also cause wastes but in a particular way. Muda, mura, and muri cause inefficiencies and high costs in any operation.

What are the seven types of wastes or “muda”?

A lean system declares war on wastes or “muda”
These wastes are classified into 7 types:
1. Over-production waste
2. Processing waste
3. Transport waste
4. Waiting-time waste
5. Inventory waste
6. Motion waste
7. Defects