Guide: Muda, Mura and Muri
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Daniel Croft
Muda, Mura and Muri are three important concepts of waste which are part of the Toyota Production System which revolutionized manufacturing in the automotive industry. These types of wastes are important to understand as they impact efficiency and productivity, by understanding these concepts you will be able to start addressing some key wastes that cause process inefficiencies and make your business leaner and more competitive in the market.
Table of Contents
The first type of waste we will look at is Muda. Muda refer to any activity that does not add value to the end product or service from the customers perspective and is essential non value adding.
An easy way to understand what categorizes as value add or waste is to think about each activity and consider if you could break down the process and invoice the customer for each individual step. Which steps would the customer not want to pay for? Those steps are likely waste.
Businesses can increase productivity and cut costs by locating and removing waste. Waste comes in a range of forms that are frequently recognized in lean manufacturing as the 8 wastes
You can get an in-depth understanding of the 8 Wastes with our guide. However, here is a brief explanation of the 8 types of Muda waste:
- Transportation: Unnecessary movement of goods or materials.
- Inventory: Excess stock or materials beyond what is required.
- Motion: Unnecessary physical movement of people or equipment.
- Waiting: Idle time or delays in the workflow.
- Overproduction: Producing more than what is demanded by the customer.
- Over processing: Adding more value than necessary to a product or service.
- Defects: Errors or mistakes that require rework or correction.
- Skills: Underutilization or not fully utilizing the skills of employees.
Businesses should reviews their processes and identify non-value-added activities, and initiate improvement activities to either eliminate or reduce Muda (waste).
There are some Lean tools that are ideal for this one is conducting a simple waste walk where you walk the process looking at each step of the process as it is happening (going Gemba) and assessing whether each step is value adding or wasteful to the process. By doing this you should then gain an understanding of the process waste a list the activities which are wasteful and need to be eliminated or reduced where you cannot remove it.
Feel free to use our Waste walk template to support you with your waste walks.
Another useful tool is process mapping which is where you review the process and map out every activity and decision point in the process looking at the process as it happens commonly referred to as the “current state”.
Value add analysis example
Once the current state is mapped out a team of the process stakeholders can then objectively look at each step of the process and decide if it is value add or waste. If it is identified as waste actions can be taken to remove or reduce its impact on the process. Once this has been completed you can refer to this as your “future state map” which will then form the plan of how the process will look in the future after the various improvement that have been identified have been implemented.
Mura – Unevenness Reduction
Mura is the next type of waste which is a waste of variation in the process, which can lead to inefficiencies as waste as production demand go up and down in a given period of time. Mura waste results in unpredictability and the unevenness of the process can result in longer production lead times and result in Muda waste such as Waiting, excess inventor or of over production in times where orders reduce. To get rid of mura, a seamless and reliable workflow is important. Here are a few typical reasons for unevenness:
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- Imbalanced workloads: Unequal distribution of work among team members or processes.
- Inconsistent process times: Significant variations in the time required for different steps causing bottlenecks as the product or service flows through the value chain.
- Unpredictable demand: Fluctuations in customer demand, leading to overproduction or underutilization of resources. This can often be cause by seasonality or secular trends in the market.
- Lack of standardized work: Absence of clear guidelines and standard operating procedures, which leads to operators doing processes differently and taking a different amount of time.
To address the Mura waste businesses should focus on the following methods:
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- Aligning workloads: Understand how tasks are distributed and redistribute workloads as necessary to maintain evenness. A useful technique for this can be a Kanban System.
- Standardizing processes: Establish clear procedures, standardize work instructions, and minimize variations where possible.
- Leveling demand: Use techniques like flexible production systems or just-in-time (JIT) delivery to smooth out fluctuations in demand.
Muri – Overburden Avoidance
Muri is the next type of waste in the Toyota Production System and is used to describe an excessive load placed on employees, machinery, or processes. Muri waste can occur when demands or tasks become greater than what employees and process are able to process. This can lead to employee burnout, mistakes, and decreased productivity.
In order to deal with muri, take into account:
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- Workload analysis: Determine whether the workload being placed on people or machines is within their capacity.
- Ergonomics: Make workstations and process more efficient and less physically taxing by optimizing them. A useful technique for this would be to implement 5S workplace organization.
- Standard work: Use Standard work instructions to establish realistic standards and provide adequate training and resources to meet those standards.
- Continuous improvement: Encourage employee feedback and present chances for procedure improvement.
Conclusion
Muda, Mura, and Muri are foundational topics in the Toyota Production System, understanding and addressing these types of waste can ensure the business runs leaner, smoother and more efficient, resulting in benefits for both the company and its customers. Regularly reviewing and refining processes to eliminate waste can leader to sustained improvements and growth of the business.
References
- Smith, S., 2014. Muda, muri and mura. Lean & Six Sigma Review, 13(2), p.36.
A: “Muda, mura, and muri” is a concept derived from the Toyota Production System (TPS) and is often referred to as the three M’s. It is a way of categorizing and addressing different types of waste and inefficiencies in a process or system.
A: “Muda” refers to any activity or process that is wasteful and does not add value to the final product or service. It includes activities such as overproduction, waiting, unnecessary transportation, excess inventory, unnecessary motion, defects, and unused employee creativity or skills.
A: “Mura” refers to unevenness or inconsistency in a process or system. It represents variations, imbalances, or irregularities that result in inefficiencies and disruptions. Examples of mura include uneven workloads, fluctuating demand, inconsistent production processes, and imbalanced resource allocation.
A: “Muri” refers to overburden or excessive strain placed on people, equipment, or processes. It occurs when tasks or workloads exceed the capabilities or limitations of individuals or resources, leading to stress, errors, accidents, and reduced productivity. Muri can be physical, mental, or emotional.
A: To address muda, mura, and muri, organizations can implement various improvement methodologies such as Lean Six Sigma, Value Stream Mapping, and Kaizen. These methodologies aim to identify and eliminate waste, streamline processes, balance workloads, reduce variation, and remove excessive strain. Continuous improvement, employee involvement, and a focus on quality are key elements of addressing these issues.
A: By addressing muda, mura, and muri, organizations can achieve several benefits, including increased efficiency, improved productivity, reduced costs, enhanced quality, better customer satisfaction, optimized resource utilization, and a more conducive work environment. It also fosters a culture of continuous improvement and innovation.
A: No, the concepts of muda, mura, and muri can be applied to various industries and processes beyond manufacturing. While they originated in the manufacturing context, the principles can be adapted and applied to service-oriented organizations, healthcare, software development, project management, and other sectors to identify and eliminate waste, improve efficiency, and enhance overall performance.
Author
Daniel Croft
Daniel Croft is a seasoned continuous improvement manager with a Black Belt in Lean Six Sigma. With over 10 years of real-world application experience across diverse sectors, Daniel has a passion for optimizing processes and fostering a culture of efficiency. He's not just a practitioner but also an avid learner, constantly seeking to expand his knowledge. Outside of his professional life, Daniel has a keen Investing, statistics and knowledge-sharing, which led him to create the website learnleansigma.com, a platform dedicated to Lean Six Sigma and process improvement insights.
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