- Lean Manufacturing
- Lean Service
- Case Studies
- About Us
- Contact Us
Understanding Waste, Unevenness and Overburden – Muda, Mura and Muri
The definition of Lean is to reduce waste. Here we will look at the THREE types of waste the may occur in a process. We will explore the “7 wastes”, often referred to as Muda, and update our understanding of the other two, lesser know wastes Mura – the waste of unevenness, and Muri – the waste of overburden. These two wastes are often overlooked at we journey along the Lean path.
As you look into Lean, you come across the 7 wastes (or the 8 wastes, depending on which “Lean school” you went to!). Developing a “Waste elimination culture” is a key aspect of Lean. However the Toyota Production System, which is the foundation for all modern lean methodology, also talks about the additional wastes of unevenness and overburden; while there are not mentioned very often, they go a long way to explaining what is going on in today’s busy company.
The 7 Wastes (Muda)
When we talk about waste in a Lean sense, we are referring to the activities we do each day that our customer doesn’t pay us for, not just the waste that ends up in the bin. In summary the seven categories for the waste are:
Transport is the excessive movement of components and materials from one location to another, without adding value
Inventory is the cost of having finished components, work in progress and raw materials and consumables within your factory walls. While a level of inventory is necessary to keep your factory running smoothly, it is still money spent and needs to be viewed as such.
Motion outlines the mini movement of people and components within a manufacturing cell or factory; not to be confused with transport, which is defined as the larger scale movement.
Waiting is often the unseen waste, as it is disguised in many ways; waiting includes for information and instruction, as well as not having the parts, tooling or machine available when needed
Over production is another waste hidden as using our time well in the factory; we often see companies making stock to keep our people “busy”. It needs to be managed carefully as it masks the uses of resources as something productive when it may be just wasteful.
Over processing is another activity hard to identify in a high quality organisation but it does show itself through value stream mapping and involving our teams to question everything they do
Defects and rework are obvious wastes in manufacturing but often seen as acceptable waste due to poor quality and processes; holding your company the right level of quality can go a long way to improving overall quality and eliminating this obvious waste.
The Waste of Unevenness (Mura)
The waste of unevenness can often been seen through the fluctuation in schedule and demand on our people, particularly for seasonally influenced industries, like food manufacturing, and seasonal variations, like Christmas and the End of the financial year, or even at the end of the sales month.
While we understand the concept as we experience it on a regular basis, there are few key strategies as to how we tackle this in an agile manufacturing environment. Here are three concepts to help reduce the waste of unevenness:
1. Buffer flow with internal supermarkets
Determine where in your process it makes sense to hold work in progress and design your systems around these points. You must consider the risks when making only to stock. Reducing lead times makes making to order a preferred option, depends on your industry and customer expectations.
2. Review Data to Predict Demand
Can we see patterns from previous years to determine how we can smooth out the low times by making ahead to soften the busy times? Use this time for improvements and trials. Understand the real costs of your boom and bust cycles.
3. Isolate your Factory from Customer Demands
Consider how you can balance the efficiency of your factory while still providing your customer a quality product, at a good price and a great lead-time. Particularly in make to order businesses, with little order cancellation, having the factory removed from customer installation demands can help improve the efficiency of the factory, as you know the product will still be needed and paid for, but just not when you initially expected it to.
The Waste of Overburden (Muri)
While overburden is the least discussed of the three wastes, at TXM we believe it is the greatest challenge in current times. Everywhere we go we are feeling busier, trying to do more with less. While people can sustain this for a short time when there is a true crisis, we find companies are permanently working at the old “crisis” level and it’s just not sustainable.
Before your factory or office process can begin to remove overburden, it is important to create a stable work platform. The stable platform needs Work Standards which form the base of your defined processes. Once these standard are set in place, they can be trained to, audited to and maintained over time. Improving stability across staffing levels, equipment utiitstation (OEE) and reliability, material quality and supply is essential for identifying and removing the waste from any workplace
Your team must also be realistic with scheduling and planning resources. Allow for rework, training and absenteeism across your plan. There is no point having a work plan and “hoping” all of your team is always there and on their best game. Create a system that is designed to succeed, and robust enough to do so,most of the time.
Fujio Cho, Vice Chairman of Toyota Motor Corporation, describes the use of lean tools and lean management as “We get brilliant results from average people managing brilliant processes. We observe that our competition often gets average (or worse) results from brilliant people managing broken processes.”
So start to fix your broken processes and let your people do their best. By taking the time to investigate the wastes, evenness and overburden in your business you will be able to create stability and reduce waste,