Identifying waste using the 3 Ms can help you more easily set goals and create conditions that avoid unnecessary repetition of efforts (muda), unevenness of those efforts (mura), or efforts that cause strain (muri).
By focusing improvement activities on eliminating the non-value-adding parts of the production process, balance between capacity and load can be achieved.
Muda refers to waste in the most basic sense: any activity that doesn’t add value. There are seven wastes of manufacturing identified as muda, each one a common cause of loss during production. It includes: defects, waiting, motion, inventory, overproduction, over processing, and transportation. These are relatively easy wastes to spot in your facility, but the concepts of mura and muri warrant a little more explanation. Let’s take a closer look.
Mura – Unevenness in process or production
Mura, when translated refers to unevenness or irregularity, specifically in production levels. occurs because of wasteful allocations of materials or people. For example, employees might be directed to work intensely during the morning shift, which results in a lack of work to do in the afternoon. This start-speed up-stop scenario can be unhealthy for both workers and machines and can lead to unnecessary fatigue, stress, breakdowns, and accidents.
Muri – Overburden of Assets
Muri is the consistent overburden of equipment, facilities, and people. Muri pushes machines or people beyond their natural limits, causing fatigue and stress and increasing the likelihood of an accident. Overburdening equipment can also lead to breakdowns and increased defects, which results in wasted materials and products.
Ask yourself…
When you head out on a Gemba walk, keeping muda, mura, and muri in mind can provide a useful starting point for looking at your operations. The questions below can help you determine whether these wastes and misuses of resources are present in your facility and what activities are not adding value for the customer.
What Is Creating Waste (Muda)?
Look for and identify:
- Poorly defined or unnecessary activities
- The 7 (or 8) types of waste
- Damaged tools or machinery
What Is Creating Unevenness (Mura)?
Look for and identify:
- Inconsistent output
- Fluctuations in quality
- Stop and Go processes
- Accumulation and overproduction
What Is Creating Strain (Muri)?
Look for and identify:
- Overburdened workers
- Overburdened machinery
- Unbalanced work loads
Poor Visibility = Poor Process and Outcome
Look for and identify:
- Poorly defined directions
- Confusing signals
- Metrics that are not easy to read or understand
Muda, mura, and muri are three separate categories for waste, but are also heavily connected to each other; addressing one area of waste will affect the other two wastes. Every strategy in the Lean toolbox can be used to reduce these wastes. For instance, if you are looking for a way to level the production in your manufacturing line to eliminate the waste of overproduction, implementing a Kanban system is a visual system to ensure production only happens when needed. It will be important in your journey to Lean to analyze your facility and identify areas of wastes. Take a Gemba walk and talk to frontline employees and develop a plan to address these wastes.