Almost everyone who has heard of Lean identifies waste in Lean as 7 waste or Muda (as identified under the original Toyota Production System). It is often said that almost all organizations have one or more of the 7 waste in their business processes.
7 waste of Lean
- Transport: Movement of goods that does not add any or little value to the process.
- Inventory: Storing more material, parts or products (intermediate or finished) at a time than is required by the customer.
- Motion: Unnecessary Movement of workers that does not add any or little value to the process
- Waiting: Refers to idle time when workers, material, information, tools, etc. are either not ready or waiting for work for any reason
- Overproduction: Processing more than that is required and adds no value to the process
- Over-processing: Producing more than customer demand. Considered to be the worst kind of waste as it hides other 6 wastes.
- Defects: Work that contains errors, mistakes, rework or does not have certain characteristics, considered to be important by the customer.
But are these the real reason for all the inefficiencies and defects in the business processes?
The real reason for these 7 waste or Muda is Muri and Mura.
Muri: It is the Waste of unreasonableness or overburden on a person or machine. It concerns the inability of the process to perform as per customer demand. It is also associated with the under-utilization of resources (workers, material & equipment). While overburden on workers & equipment results in stress & breakdowns, under-utilization results in workers & equipment lying idle or waiting for work.
Mura: Mura refers to waste of variation or unevenness in production volume, which broadly means unplanned utilization of resources. In large manufacturing organizations, production is done at a set pace and a large inventory is maintained to deal with sudden spikes in demand. But the same large inventory proves to be a huge liability whenever demand falls.
Real Cause of waste
The real cause for waste in business processes is Muri & Mura, which becomes visible in any one or more forms of Muda or 7 waste. Let us understand this with an example. Mura or Unevenness in production results in scenario where at the starting days of a production cycle (weekly or monthly), most of the workers and equipment either don’t work or work very slowly. As the time of production cycle end is near, workers tend to work faster with equipment to meet the production targets. Many times, this may create scenario where workers work on overtime. Similarly, extra burden on machinery may increase their maintenance costs and breakdowns. All this increases the production costs and also leads to creating of defects and other waste in the process.
Lean concept is based on the simple idea of eliminating waste elements from production processes and giving the maximum value to the customers at minimum of costs. But it has been witnessed that most of the companies struggle to eliminate waste from their processes. This is because these companies tend to address the symptoms rather than the root cause of waste. Only the 7 waste or Muda which is visible on the surface is identified. Temporary solutions are devised and implemented which work for some time as the identified waste disappears. But no effort is made to identify the real culprits or root cause which is Muri & Mura which create conditions for Muda to happen.
Finally, the root cause which persists beneath the surface emerges sometimes later as another waste.