Lean is a core part of Lean Six Sigma, and involves removing inefficiencies from your systems and processes by removing Muda (waste), Muri (overburden) and Mura (unevenness). It is about concentrating your efforts on what gives value to your customers, and removing everything else.
It is often called ‘Lean Manufacturing’ as it is often applied to a manufacturing workplace, but I’ve seen it increasingly applied to other industries such as service, which is sometimes referred to as Lean Enterprise .
Toyota Production System (TPS)
Lean developed from the Toyota Production System (TPS) developed by Toyota between 1948 and 1975. It was founded on two principles:
- Just in Time – Making only what is needed, when it is needed
- Jidoka – Automation where humans intervene when needed (essentially now the lean concept of Poka Yoke or Mistake Proofing)
TPS introduced a lot of the jargon of Lean – the aim of TPS was to remove ‘mura’ (inconsistency’) and remove ‘muri’ (overburden) which contributes to ‘muda’ (waste).
The removal of mura (inconsistency) is now essentially the aims of Six Sigma, and the removal of muda (waste) (and therefore also muri (overburden)) has become what is known as ‘Lean’.
What are the ‘7 Wastes’ (Muda)?
The key aim of Lean is removing the 7 wastes from your company, as these are the main ways that you waste money, time and effort. These are:
- Transportation – moving goods / people between different locations
- Inventory – having more stock than is required, tying up money which could be used better, getting in the way and potentially decreasing in value
- Motion – more activity in a process than adds value
- Waiting – time when goods are not being worked on and people are not creating value
- Overproduction – producing more end product than is required
- Overprocessing – processing that doesn’t add value that the customer needs
- Defects – costs from unusable products, or rework costs
An optional 8th waste is:
- Potential / Skills – staff working below their maximum capacity
By removing these wastes from your processes when designing your procedures, you can greatly improve the outcomes of your Six Sigma projects. There is more information on the 7 Wastes (Muda) page.
Lean Six Sigma
Combining Lean principles and tools with Six Sigma for a more complete process improvement framework is called ‘Lean Six Sigma’. The Lean aspect removes the waste from the system, and Six Sigma removes the variation, to create a predictable, efficient and consistent output.
There are some useful tools that can be borrowed from Lean for using in your work / Six Sigma projects.
- Just In Time production (JIT) – Producing items at just the point when they are needed in the required quantity, to reduce waste and reduce working capital requirements
- 5S / CANDO – Organizing your workplace to be efficient, organized and clean (tour ready)
- Poka Yoke (mistake or error proofing) – designing your processes so that either the errors can’t happen, or if they occur they are immediately found and fixed
Incorporating these Lean tools and principles in your Six Sigma project will magnify the gains from your Six Sigma projects.