Lean Manufacturing

A Closed Mitt and an Open Mind

By Jon Miller Published on July 26th, 2007

Sorting through old documents as part of my regular 5S at the office I came across another consulting firm’s Lean training materials, collected about a decade ago. These explained Lean manufacturing and the idea of eliminating waste using the acronym CLOSED MITT. I am told this comes from Boeing, or at least that it was popularized there.
CLOSED MITT stands for the 10 types of waste (yes, ten) commonly found in all processes. They are:
Saying that complexity is a waste is like saying that badness is a sin. It is more of a description of a state containing waste, or a cause of waste. Adding 3 more wastes to a list of 7 types of waste that has been sufficient in steering Toyota to a position of global leadership in operational excellence, may be an example of complexity.
Motion waste could be considered a waste of labor. People waiting could also be included here. The so-called 8th waste of underutilized creativity could also be included here.
No arguments here. Overproduction tops the list of the canonical 7 wastes.
Space not utilized effectively can certainly be considered a waste.
This is a waste that does not get nearly enough attention, and surrounds us in our daily lives. Stand in a circle for 30 minutes, wherever you are, and I guarantee you will find a way to get rid of this waste and save real money.
Defects or correction waste is one of the 7 types of waste.
This could be either the waste of defects or processing waste in the case of extra materials used to complete a process.
Idle Materials
This is another way of saying inventory, either as raw materials, work in process, finished goods or supplies. This begs the question: are non-idle materials, such as a work piece that is being assembled or machined, not waste? If you are adding value to a piece of material that is not needed, this is overproduction, resulting in inventory waste. Idle materials also may be stored as a service, as warehouses or storage companies do. In this case the idle materials themselves (belonging to a customer) are the raw materials for a service (storage) which customers pay for, so it is not waste.
Time certainly can be wasted, but this is too broad and vague. Wasted human time can be either waiting or motion or processing. Wasted machine time is most often processing waste. Time can be wasted, but it is not a waste, or a type of waste.
Movement of material that adds no value is by definition a waste.
It’s ironic that after adding to the original list of 7 wastes, the author of CLOSED MITT did not reflect on “complexity” being at the head of this enlarged list. If we use Occam’s Razor, a principle that states that the simpler theory is best (named after the 14th-century English logician and Franciscan friar William of Ockham) a shorter list seems to be in order.
We need to keep an open mind in finding and getting rid of waste. Certainly no waste should be allowed to persist a moment longer than necessary, even if we do no agree on what to call it. I have always found the 7 types waste to be sufficiently descriptive for the wastes around me.
For example “energy” waste from the list above can be included in the waste of processing, since more resources than necessary are being used to perform the process, and resources take energy in some form. You may have a near-perfect process, but if the building is using too much air conditioning or if lights are left on where not needed, in a macro sense there is still processing waste (energy waste).
The “space” waste above should rightly be considered inventory waste since space is an asset you are paying for if it is owned, or if the space is leased it should be considered as a form of processing waste since it is a variable expense that is unused but paid for, heated, lighted, cleaned, etc. but adding no value.
Although not typically included in a list of wastes, we should consider environmental contamination to be an example of making defects. The defect created is not a product but the natural environment around the process. At some point this environmental damage (defect) will need to be corrected or the environment (product) will become unusable (scrap).
Another type of defect is health and safety losses in the workplace. Safety is often in a separate category from the 7 types of waste, or “the 6th S” add-on to the 5S, but “safety first” should be taken seriously by any serious Lean effort and must be a prerequisite and foundation of a Lean system. A safety incident is an example of a defective process that needs correction.
Simpler theories, shorter lists, and smaller formulas are better because they are easier to test, remember and apply.

  1. Tom

    July 27, 2007 - 6:01 am

    Maybe PIE is a shorter, and therefore better, description. In this case, though, we don’t want a bigger slice of the PIE, we want a smaller piece – we want to get Lean.
    P – Processes; wastes that are due to “the way we do things around here”; lack of Standard Work
    I – Individuals; wastes due to poor training, idle employees, absenteeism and, unfortunately, the occassional bad apple;
    E – Energy; wastes in movement of goods, materials, people, etc.
    Have a smaller slice of the PIE and you’ll get Leaner.

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