Key Principles of Lean Six Sigma
Lean Six Sigma takes the features of Lean and of Six Sigma and integrates both to form a magnificent 7 set of principles. The principles of each approach are not dissimilar, and the integrated set produces no surprises.
The 7 principles of Lean Six Sigma are listed below:
1) Focus on the customer
The customer’s CTQs describe elements of your service or offering they consider Critical To Quality. Written in a way that ensures they are measurable, the CTQs provide the basis for determining the process measures you need to help you understand how well you perform against these critical requirements. Focusing on the customer and the concept of value-add is important because typically only 10–15 per cent of process steps add value and often represent only 1 per cent of the total process time. These figures may be surprising, but they should grab your attention and help you realise the potential waste that is happening in your own organisation. As you improve your performance in meeting the CTQs, you are also likely to win and retain further business and increase your market share.
2) Identify and understand how the work gets done
The value stream describes all of the steps in your process – for example, from a customer order to the issue of a product or the delivery of a service, through to payment. By drawing a map of the value stream, you can highlight the non-value-added steps and areas of waste and ensure the process focuses on meeting the CTQs and adding value. To undertake this process properly, you must ‘go to the Gemba’. The Japanese word Gemba means the place where the work gets done – where the action is – which is where management begins. Process stapling involves you spending time in the workplace to see how the work really gets done, not how you think it gets done or how you would like it to be done. You see the real process being carried out and collect data on what is happening. Process stapling helps you analyse the problems that you want to tackle and determines a more effective solution for your day-to-day activities.
The value stream reveals all of the actions, both value-creating and non-value-creating, that take your product or service concept to launch and your customer order through the supply chain to delivery. These value-creating and non-value-creating actions include those to process information from the customer and those to transform the product on its way to the customer.
3) Manage, improve and smooth the process flow.
This concept provides an example of different thinking. If possible, use single piece flow, moving away from batches, or at least reducing batch sizes. Either way, identify the non-value-added steps in the process and try to remove them – certainly look to ensure they do not delay value-adding steps. The concept of pull, not push, links to our understanding the process and improving flow. And it can be an essential element in avoiding bottlenecks. Overproduction or pushing things through too early is a waste.
4) Remove non-value-adding steps and waste.
Doing so is another vital element in improving flow and performance. Generally, there are 8 forms of wastes (also known as Muda in Japanese ). Of course, if you can prevent waste in the first place, then so much the better.
5) Manage by fact and reduce variation.
Managing by fact, using accurate data, helps you avoid jumping to conclusions and solutions. You need the facts! And that means measuring the right things in the right way. Data collection is a process and needs to be managed accordingly. Using Control Charts enables you to interpret the data correctly and understand the process variation. You then know when to take action and when not to.
6) Involve and equip the people in the process.
You need to involve the people in the process, equipping them to both feel and be able to challenge and improve their processes and the way they work. Involving people is what has to be done if organisations are to be truly effective, but, like so many of the Lean Six Sigma principles, it requires different thinking if it is to happen.
7) Undertake improvement activity in a systematic way.
DMAIC of Six Sigma comes into play here: Define, Measure, Analyse, Improve and Control. One of the criticisms sometimes aimed at ‘stand-alone’ Lean is that improvement action tends not to be taken in a systematic and standard way. In Six Sigma, DMAIC is used to improve existing processes, but the framework is equally applicable to Lean and, of course, Lean Six Sigma. Where a new process needs to be designed, the DMADV of Design for Six Sigma (DFSS) method is used. Less is usually more. Tackle problems in bite-sized chunks and never jump to conclusions or solutions.
(Reference : Lean Six Sigma For Dummies®, 2nd Edition by John Morgan and Martin Brenig-Jones, Published by John Wiley & Sons, Ltd)
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