The Missing M & M

In Lean Basics
March 8, 2017
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In today’s economy many companies are looking for cost savings. Eliminating muda (waste) is the focus of most lean manufacturing efforts. But two other M’s are just as important to making lean work. In fact, focusing on only the eight wastes of muda can actually hamper productivity. Lean is about the elimination of muda, muri, and mura.

The three M’s are:

Muda – Non-value-added activities associated with the 8
wastes

Muri – Overburdening people of equipment

Mura – Unevenness in your system

Focusing on muda is the most common approach to implementing lean because it is easy to identify and eliminate waste. Unfortunately, those companies fail to understand the connection of the three M’s. Stabilizing the system and creating balanced flow is essential to eliminating the three M’s

Unevenness happens when volumes move up and down temporarily. This is created by changes in the production schedule, previous processes “pushing” material to the next process, or perhaps empty containers stacking up at processes. Customer orders, machine breakdowns, quality problems, and large production lots are all causes of mura. Leveling out the schedule, heijunka, is fundamental to eliminating mura, which is fundamental to eliminating muri and muda.

Systems that have starts and stops, overutilization then underutilization, do not lend themselves to quality, standardization of work, productivity, or continuous improvement. Taiichi Ohno explains this point from the tortoise and the hare fable:

The slower but consistent tortoise causes less waste and is much more desirable than the speedy hare that races ahead and then stops occasionally to doze. The Toyota Production System can be realized only when all the workers become tortoise.

You can start eliminating muri and mura in your process today through the same observations for eliminating muda. As you watch your process try to understand what is happening to cause the fluctuations resulting in the unevenness. Look for signs of overburdening people physically (muscles tightening, gripping tightly, straining, excessive reaches, and others) and mentally (watch employees’ eyes, frowning, squinting).

As you look for more gains in your process don’t focus just on muda but all three M’s. Hopefully with your new eyes for improvement you will not forget the other M’s. Muda, Muri, and Mura are all interconnected and eliminating all sources of inefficiencies will produce the most gain.