Muda (Japanese term)
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Muda (無駄) is a Japanese term for activity that is wasteful and doesn't add value. It is also a key concept in the Toyota Production System and is one of the three types of waste (Mura, Muri) it identifies. Waste reduction is an effective way to increase profitability.
A process adds value by producing goods or providing a service that a customer will pay for. A process also consumes resources. Waste occurs when more resources are consumed than are necessary to produce the goods or provide the service that the customer actually wants.
The prominence given to muda as waste means that whilst many Lean practitioners have learned to see muda they fail to see in the same prominence the wastes of mura (unevenness) and muri (overburden). Thus they are so focussed on getting their process under control that they do not give enough time to process improvement by redesign.
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[edit] The Seven Wastes
One of the key steps in Lean and TPS is the identification of which steps add value and which dont. By classifying all the process activities into these two categories it is then possible to start actions for improving the former and eliminating the latter. Some of these definitions may seem rather 'idealist' but this tough definition is seen as important to the effectiveness of this key step. Once value-adding work has been separated from waste then waste can be subdivided into 'needs to be done but non-value adding' waste and pure waste. The clear identification of 'non-value adding work', as distinct from waste or work, is critical to identifying the assumptions and beliefs behind the current work process and to challenging them in due course. Breakthroughs in SMED and other process changing techniques rely upon clear identification of where untapped opportunities may lie if the processing assumptions and beliefs are challenged.
The expression "Learning to see" comes from an ever developing ability to see waste where it was not perceived before. Many have sought to develop this ability by 'trips to Japan' to visit Toyota to see the difference between their operation and one that has been under continuous improvement for thirty years under the TPS. Shigeo Shingo, a co-developer of TPS, observed that it's only the last turn of a bolt that tightens it - the rest is just movement. This level of refined 'seeing' of waste has enabled him to cut car body die changeover time to less than 3% of its duration in the 1950s. Note that this period has allowed all the supporting services to adapt to this new capability and for the changover time to under multiple improvements. These multiple improvements were in new technologies, refining value required by 'downstream' processes and by internal process redesigns.
The following Seven Wastes identify and classify resources which are commonly wasted. They were identified by Toyota’s Chief Engineer, Taiichi Ohno as part of the Toyota Production System[1]:
[edit] Defects
Quality defects prevent the customer from accepting the product produced. The effort to create these defects is wasted. New waste management processes must be added in an effort to reclaim some value for the otherwise scrap product.
[edit] Overproduction
Overproduction is the production or acquisition of items before they are actually required. It is the most dangerous waste of the company, because it hides the production problems. Overproduction must be stored, managed and protected.
[edit] Transportation
Each time a product is moved it stands the risk of being damaged, lost, delayed, etc. as well as being a cost for no added value. Transportation does not make any transformation to the product that the consumer is disposed to pay for.
[edit] Waiting
Refers to both the time spent by the workers waiting for resources to arrive, the queue for their products to empty as well as the capital sunk in goods and services that are not yet delivered to the customer. It is often the case that there are processes to manage this waiting.
[edit] Inventory
Inventory - be it in the form of Raw Materials, Work-In-Progress (WIP), or Finished Goods - represent a capital outlay that has not yet produced an income either by the producer or for the consumer. Any of these three items not being actively processed to add value is waste.
[edit] Motion
As compared to Transportation, Motion refers to the producer or worker or equipment. This has significance to damage, wear, safety. It also includes the fixed assets, and expenses incurred in the production process.
[edit] Overprocessing
Using a more expensive or otherwise valuable resource than is needed for the task or adding features that are designed in but unneeded by the customer. There is a particular problem with this item as regarding people. People may need to perform tasks that they are over qualified for so as to maintain their competency. This training cost can be used to offset the waste associated with overprocessing.
[edit] Other candidate wastes
Other sources have proposed additional wastes. These may work for the proposers or they may overlap or be inconsistent with the originals which came from a coherent source.
[edit] Skill
Organizations employ their staff for specific skills that they may have. These employees have other skills, it is wasteful to not take advantage of these skills as well. "It is only by capitalizing on employees' creativity that organizations can eliminate the other seven wastes and continuously improve their performance."[citation needed]
[edit] Safety
unsafe work areas creates lost work hours and expenses.[citation needed]
[edit] Information
age of electronic information and enterprise resource planning systems (ERP) requires current / correct master data details.[citation needed]
[edit] References
- ^ Toyota Production System, Ohno, Taiichi, 1988, Productivity Press
