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Muda, mura, muri



Published November 11, 2010
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Over the past few years we've tackled what is considered to be the major focal point of any Lean enterprise: the complete elimination of waste. These wastes, for any manufacturing environment, are often expressed with an easy to remember acronym-cum-acrostic such as D-O-W-N-T-I-M-E. DOWNTIME wastes are:

Defects – scrap or defective product
Overproduction – producing information or materials too soon or in greater quantities than needed
Waiting – people and/or equipment that are idle, waiting for something to work on
Non-utilized people – not using everyone's full range of skills and talents
Transportation – excessive movement of materials
Inventory – having too much raw material, work-in-process, and finished goods
Motion – unnecessary movement: walking, reaching, twisting, bending, etc.
Extra processing – additional work or processing that is unnecessary or required due to poor designs or inadequate equipment and technology

While many people know about these wastes, most are unaware of two additional wastes that are present in every operation, factory, office, and warehouse; in short, like waste (muda), these are present everywhere. They are irregularity, inconsistency or unevenness (mura) of work, and unduly strenuous or burdensome work (muri).

Mura
Mura, oftentimes referred to as unevenness, occurs whenever there is an interruption in the smooth and consistent flow of materials or information. In his book Gemba Kaizen, A common sense approach to Management (McGraw-Hill, 1997), Masaaki Imai defines mura as "irregularity or variability." While muda is easy to see in the workplace, mura is much more difficult and can be seen only by following the rule of "genchi genbutsu," or "go and experience."

In order to see the waste of mura or unevenness you must go to the actual place where the work or activity is occurring and experience the conditions for yourself. It's not enough merely to hear about uneven conditions or to direct others to correct the imbalance. Good leaders must experience the conditions that their employees are experiencing in order to fully understand what is happening in order to develop and implement effective countermeasures.

If any or all of this sounds as though it doesn't apply to your own office or shop environment, then I would advise you to "genchi genbutsu" – go and experience – the daily environment that your employees live and work in every day. What do you see? If you see one or more employees working very hard while others are not, you have mura. There is an imbalance or unevenness in the work that is causing one group of people – or machines – to have to work at a different pace than another.

Oftentimes this happens when a lesser experienced employee is assigned a position for which he or she is inadequately prepared. This lack of preparation is entirely due to our (management's) failure to provide proper instruction and skills development for that person. When this person's output takes more time than another's, the entire process inevitably slows down to the pace of the lesser experienced person.

When you understand what mura is you can begin to see it or experience it for yourself. Place yourself on the line and see what happens when you – the lesser experienced "boss" – can't keep up with the pace. You've just uncovered mura.

Many plants that I've been in have the same number of slitter rewinders as they have presses. The speeds of the presses will often out-produce the slitters, causing pallets of work-in-process to pile up. This waste of inventory (muda) that is discovered by the manager who goes and experiences this condition for him or herself (as opposed to looking at inventory variation numbers on a spreadsheet) uncovers mura between the press and slitter operations. The varying speeds of the equipment cause an imbalance in the flow of the work. A countermeasure for this is to assign more than one slitter to keep up with a press; I've even recommended that slitter rewinders have wheels to move them to where they're needed to help eliminate these increases of work-in-process.

The same holds true for the office, especially in the order entry function. Many printers will try to assign clients to a customer service representative by geography, account manager, or size, all in an effort to spread the workload or eliminate mura.

Muri
Muri is defined by Imai as "strain or difficulty." Muri occurs whenever people or equipment are being overburdened or overstressed. Take the example of the lesser experienced worker; not only is he or she unable to keep up with the flow of work (mura) but he or she is probably stressing over that very fact (muri) and is more likely to become injured or make a mistake. None of these outcomes are acceptable, yet we set the stage for just such an occurrence each and every day that we assign people to tasks or jobs that they have not been adequately prepared to perform. They stress out when they fall behind, we stress out because they are falling behind, and the vicious circle goes around and around until something (or someone) breaks.

When you see a person who is hustling and sweating while others are not, there is muri or strain, and it may very well be caused by mura or imbalance in the workload. When we ignore proper maintenance on our equipment – when we "run until it breaks" – we are causing muri or strain on the equipment.
Too often in today's work environment we glorify the "firefighter" who always rushes in to put out the fire before rushing off to another emergency, or the "gunslinger" who rides into town to save the day. This misguided and romanticized notion of heroic efforts helps to prevent us from seeing muri as it really is: a terrible waste of time and effort to correct something that should never have been out of balance in the first place.

In Laws, Plato wrote the following in 360 BCE:

"If one sins against the laws of proportion and gives something too big to something too small to carry it – too big sails to too small a ship, too big meals to too small a body, too big powers to too small a soul – the result is bound to be a complete upset. In an outburst of hubris the overfed body will rush into sickness, while the jack-in-office will rush into the unrighteousness that hubris always breeds."

Our firefighters and gunslingers are the jacks-in-office who are always ready and willing to "rush into the unrighteousness" and do whatever it takes to get the job done. As long as we celebrate firefighting heroics instead of educating and promoting fire prevention, we will always have muri.

Mura, mura and muri
In our zeal to root out and eliminate the eight deadly wastes (muda) of D-O-W-N-T-I-M-E, we must not lose sight of the unevenness (mura) and overburden (muri) that may lie at the root of the problems causing muda. Proper instruction and skills development, along with effective countermeasures, will help reduce or eliminate much of the unnecessary strain and stress that we cause ourselves each and every day. Fire prevention is always less costly than firefighting.

Tom Southworth is a Lean consultant with CONNSTEP, Connecticut's Manufacturing Extension Partnership. He is a Senior Member of ASQ, an ASQ Certified Manager of Quality & Organizational Excellence, a senior member of the Society of Manufacturing Engineers, SME Lean Bronze Certified, and a certified TWI Job Instruction and Job Relations Trainer. He can be reached by email at tsouthworth@ connstep.org.



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