Making Lean "lean" is counterproductive
Lean is all about delivering more value to the customer by eliminating all waste. Taiichi Ohno, father of the Toyota Production System (TPS), defined three categories of waste:
Muda(Waste) refers to processes or activities that don’t add value. Seven types of wastes are defined in TPS: Overproduction, Over processing, Inventory, Transportation, Motion, Waiting, Defects.
Mura(Unevenness) is a type of waste caused by unevenness in production and services. It is also caused when standards are nonexistent or are not followed.
Muri (Overburden), the third category of waste is the result of tasks or processes that are overly difficult, or ones that overburden workers. This is mostly generated when workers lack proper training, have no standards to follow, or are given the wrong tools for the job.
The purpose of Lean manufacturing is to find and eliminate Muda, Mura, and Muri, in order to improve quality, safety, and efficiency. The 5S system is a good tool to start with, to de-clutter, clean, and organize the workplace using five principles: sort, set in order, shine, standardize, and sustain.
Finding and eliminating Muda is essential to reduce costs, improve efficiency, and increase profits. However, the three M’s are influenced by each other. Mura creates Muri, which in turn undermines the efforts to eliminate the seven wastes of Muda. If Mura and Muri are not addressed, the initial benefits of eliminating Muda will be inconsistent and will fade over time.
The Lean that is applied today has gradually moved away from the original philosophy. Most organizations focus only on eliminating Muda because it is a relatively easy way of identifying the low hanging fruits for improvement. However, Toyota has built its famous Production System around two more M's:Muri to create an efficient production system and Mura to create safety buffers.
The right order of implementation should then be: 1 - Set up a system with no Mura so that all processes follow a standard Takt time and their capacity achieves a reasonable level of evenness.2 - When Mura is in place, Muri will quickly surface in areas beyond the consideration of Mura such as high defect ratio or bottlenecks.And 3 - Once Mura and Muri have been treated, it will then be time to identify Muda in all the operations as described by the seven wastes.
In short, establish the right process first by removing overburden. Then empower and encourage the teams to eliminate relentlessly waste and unnecessary variation. The hunt for wastes, often considered as being the main objective of the method, is only the third step.
Forgetting Mura is symptomatic of the drifts that the Lean methodology has suffered over time. Among the principles imagined by Taiichi Ohno, a machine should never be used more than 80% of its capacity. This goes against the trend to focus on improving the OEE (Overall Equipment Effectiveness).Moreover, in the initial philosophy, Muri is about creating a mattress of resources to install the system in a comfortable, insensitive situation, where operators have time to step back and make improvements.
Of course, it takes a change of mindset not to try to maximize the OEE, and provide a surplus of resources "just in case." But it is precisely when organizations implement Lean without changing mentality that the method fails to deliver its promises. In the same way, it is not easy to get away from control procedures, which have a very reassuring character for managers, to replace them with continuous improvement.
To make Lean "lean" is therefore against the foundations of the Lean philosophy.