In “What is Waste? – Part 2” I covered the concepts of Muda, Muri and Mura (the 3M’s): where do they come from and what do they mean? Muda encompasses total “waste” and, based on my analysis, was meant to refer to the term for “heat” (Q) in the first law of thermodynamics by the Toyota engineers. And Muda is the product of two components, Muri and Mura, which refer to the two thermodynamic parameters that constitute “Heat” (Q); “temperature” (T) and “entropy” (S), respectively. Of course the other two terms in the first law are “total internal energy” (E), which Ohno calls “present capacity”, and “work” (W), which Ohno calls “real work” as opposed to unneeded work which is waste (Muda) (see “What is Waste? – Part 1“).
So where do these concepts apply in our attempt to build a Lean/TPS led organization? Let’s start with a quote from Taiichi Ohno from his book The Toyota Production System:
“…insufficient standardization and rationalization creates waste (muda), inconsistency (mura) and unreasonableness (muri) in work procedures and work hours that eventually lead to the production of defective products.” (pg. 41)
“Rationalization” is a word frequently used by Ohno to indicate activities to improve quality, reduce cost and reduce lead times. We touched on “standardization” in What is Lean? – Part 3. In the above quote, Ohno was discussing the usefulness of his Kanban (pull) system to stop the flow (jidoka) if a defective product is discovered. And, more importantly, that this defective product is due to defective work. Both are unacceptable. And the key to eliminating defects and defective work is to reduce mura and muri (and thus muda) via improved standardization and rationalization.
We can extend this example to include all the “hows” in the TPS House that I discussed in the “What is Lean” series. These “hows” (takt time, pull, stop and notify, heijunka, standardized work, and kaizen) constitute Ohno’s “rationalization”. Application of these “hows” rationalizes a systemic method to reduce mura and/or muri and thus reduce “waste” (muda). And all of these elements, working together, lead down the long, arduous but rewarding path to achieving continuous flow.
But do we know what Muda (waste) looks like? Sort of. Ohno’s 7 wastes does a pretty good job for manufacturing systems. But by breaking muda down into its component parts, we have another vantage point. It looks like:
mura: disorder, inconsistency, unevenness, unwanted variation, unwanted fluctuation (entropy)
And/or it looks like:
muri: unreasonable, impossible, overburden, overwork (temperature)
When we see these characteristics in our systems, whether that system is manufacturing, sales, marketing, planning, etc., etc., we know we are expending energy in ways that does not contribute to “real” work. We are “wasting” energy. We are impeding flow.
The key to making Lean/TPS work is to get the two pillars, JIT and Jidoka, working together. And for Jidoka to work, waste (muda) needs to be visible. Understanding mura and muri assists us in that task. And many of the assorted “hows” in the TPS House (e.g., takt time, pull, heijunka, standardized work) either minimize muda in itself and/or make muda even more visible. And when we see it, we need to stop (jidoka) and try to eliminate it (kaizen). I will get into this in much more detail in later posts.
But while we are discussing the “3M’s”, I would like to highlight one of the M’s in particular. That M would be mura (entropy). Entropy is an almost magical parameter within thermodynamics (although it is not truly “magical” since we are talking about science here). But there is this thing in thermodynamics which is called the “second law of thermodynamics”. In its simplest form it states:
“The entropy of the universe increases in the course of any spontaneous change”
In thermodynamics, the “universe” simply means the system plus its surroundings. The term “spontaneous” means that the change can create work but work is not required to drive the change. And for our purposes here, we can define entropy simply as disorder. High entropy means high disorder and low entropy means low disorder (or higher order).
So why should we care? We should care because as we go about our business, whether it be making a product or creating a service, entropy (mura) is increasing somewhere. Disorder is being created somewhere. Do you know of any machine maintenance people who expect their equipment to run better the longer it is operated? If you do, a severance package may be in order shortly. If left alone, all processes that perform work will deteriorate over time – all processes! That’s the second law at work – disorder is created. Entropy is increasing – mura is added to the system.
So is there a way to decrease entropy? Not for the universe as a whole. The second law is inviolable. But it is possible to lower the entropy in the system or parts of the surroundings, individually, as long as there is a compensating increase elsewhere.
And how do you lower the entropy of an individual subsystem of the universe? You perform work on that individual entity (force a non-spontaneous change). You build order into that subsystem by performing work on it. TPM anyone?
As a simple illustration, consider a manufacturing line producing a machined part. The line is the system and the finished part is the system output (surroundings). As the part is machined, work is done on the part and the finished part is less disordered (more ordered) than the original raw part. The entropy of the finished part has a lower entropy than the original raw part due to the work done to the part. But the system (the manufacturing line) now has a higher entropy than before and its gain of entropy is greater than the entropy loss of the finished part. Why? The line has lost raw material inventory and energy has been lost by the labor and equipment (increased disorder). Work must be done to the system by moving inventory and energy back into the system for the process to continue (the workers have lunch for instance).
Now let’s go back to the TPS House. We are trying to create “continuous flow” in the JIT pillar and the Jidoka pillar is detecting irregularities/interruption of that flow. This tells us that mura/muri is in our system and we need to reduce/eliminate that waste. That is where kaizen kicks in.
Since muri (overburden) is usually caused by mura (disorder) we need to concentrate on reducing the mura component. Therefore work must be done to the system to reduce the mura that is the cause of the flow problems – and kaizen is the method by which we apply that work to the system.
Just as work is done by the system to produce our product or service, work must be done to the system not only to improve the system but to keep it running at all.
Thus kaizen or “continuous improvement” must literally be done continually to achieve our Goal. Sporadic kaizen on a hit or miss basis will doom our Lean/TPS efforts because mura degradation is continuous, not sporadic. No matter how great our one time kaizen turns out to be, it will not last long without continued kaizen.
Here is another quote from Taiichi Ohno which, I think, reinforces this point very well:
“The key to the Toyota Way and what makes Toyota stand out is not any of the individual elements…But what is important is having all the elements together as a system. It must be practiced every day in a very consistent manner, not in spurts.”
One last thing. Remember in “What is Waste – Part 2” I pointed out that heat can result in work and work can result in heat (conservation of energy). That is also true for kaizen work. If not done effectively, kaizen can cause as much muda as it eliminates (fire-fighting comes to mind again).
How do we determine what is effective kaizen? Here we go again:
Thus the underlying principle behind TPS/Lean is the systemic creation of the shortest possible lead time for the continuous flow of materials and information in order to generate the highest quality and lowest cost.
To be effective, we must focus on continuous flow and shortest lead time! Focus on achieving JIT through Jidoka via kaizen work.
And this brings up another one last thing. Deciding who will do the kaizen work to the system can make all the difference in the world. Those people who do the daily work of the system are usually the best qualified to do the kaizen work to the system. “Unintended consequences” are the downfall of many a kaizen since “unintended consequences” usually do not fall into the “effective” category. Make sure the people closest to the system are intimately involved in the kaizen work.
And finally, let’s take a another look at Ohno’s quote that I introduced at the beginning of this post,
“…insufficient standardization and rationalization creates waste…”
Insufficient work done to the system creates waste. Sounds a bit like the “second law” and entropy to me. Smart guy!