Lean is now essentially a part of Six Sigma, and any Six Sigma course will spend a significant proportion of time explaining lean philosophies and methodologies to you. The two complement each other well, as Lean adds a lot of useful improvement philosophies and tools to Six Sigma, and Six Sigma adds some structure and systematic process to Lean.
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.
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 or capabilities
By removing these wastes from your processes when designing your procedures, you can greatly improve the outcomes of your Six Sigma projects, and save huge amounts of wasted time, money and capital in your company.
The main philosophies and tools of lean
Following a ‘lean’ system usually means following the key philosophies that Lean is founded upon, which usually involves adopting lean tools:
1 – Knowing what the customer values.
Activities which the customer values bring benefits to the company. Activities that the company carries out which aren’t valued to the customer are therefore waste, and don’t add value (even if they look as though they are adding value)
2 – Knowing the value stream.
You should know the processes involved in your production, what resources are used and where the customer value is created. This is usually achieved by way of a ‘value stream map’.
These are a type of flowchart that shows where resources (including time) are used in the company. From here you can split them into ‘value add’ that are worthwhile, and ‘waste’ which can be removed to make the process more efficient.
3 – Just in Time (pull system) using a Kanban system
Just in Time
A traditional production technique is producing products and then trying to sell them. Lean involves only producing what a customer wants and in the quantities they require, to make the system efficient and reduce wasted resources and capital. The goods are therefore created ‘just in time’ for when they are needed.
This uses a ‘pull’ system. In the push system, a procedure starts to make product when it is received from the process before it (pushed through). In a pull system, a product will only be made when the process after it needs it. The product is therefore instead ‘pulled’ from the process after instead of ‘pushed’ from the one before.
Kanban
Kanban is the system of implementing Just in Time, which comes from the Japanese for sign. It is a visual system (often using cards) where the cards dictate exactly what needs to be made and when, delivering exactly what the customer wants, when they want it. These cards are used throughout the production process to ‘pull through’ the exact quantities of product needed, minimizing Work In Progress (WIP) and maximizing efficiency.
4 – Continuous improvement.
There are always ways that you can improve what you do, to bring the customer the value they want in the most efficient way possible. Lean involves a mentality of continually trying to make the processes better, to better achieve this aim.
5 – Poka-yoke
Poka-yoke literally means ‘mistake proofing’ (it’s in Japanese). It aims to make it impossible for an error to go unnoticed, by one of two methods:
- Make it impossible for the error to occur
- Make it immediately obvious by way of an alert if an error occurs
You will see this every day in your life, with features you don’t even notice like not being able to turn on your microwave when the door is open (safety risk).
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.
These aren’t just two different concepts tacked together, they actively help each other. Having a clean, tidy and efficient workplace will make your tools more likely to be able to produce consistent outputs. Reducing variation will allow material to flow through your processes faster and more predictably and reduce defects, greatly reducing inventory and scrap waste.
Incorporating these Lean tools and principles in your Six Sigma project will magnify the gains from your Six Sigma projects.
Lean Tools
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 – This is a core lean tool, that is generally implemented before you do any other lean methods. It involves organizing your workplace to be efficient, organized, safer and clean. Afterwards, everything you need will be at your fingertips, and your workplace will be ‘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
- Value Stream maps are a very powerful tool that can quickly identify waste that can be removed from your system. It is essentially a detailed process map, that is one of the most useful tools of Lean Six Sigma that you will likely use on most projects.
Incorporating these Lean tools and principles in your Six Sigma project will magnify the gains from your Six Sigma projects.
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