Category: Lean
Lean and Six Sigma; Is it a choice or collaboration?
I regularly see posts and discussion points asking what are the differences between Lean and Six Sigma, should Lean or Six Sigma be used first, and if Lean is better than Six Sigma. I find it really puzzling that people involved in continuous improvement still have this debate, especially since the two techniques are not alternative approaches, but are complementary techniques.
Let’s take a quick look at these three questions
- What are the differences between Lean and Six Sigma?
Lean is the practical application of the Toyota Production System. Lean started out as a simple way to ensure that business were focused on the things that customers value and ensuring the activities in the business are as efficient as possible at delivering customer value. Lean focuses on process velocity, reducing waste in all forms and eliminating non value added activities. There is a bias to immediate action Lean, to ensure that waste is removed in the shortest possible time.
Six Sigma was developed by Motorola to enable effective competition against high quality imports from Japan. Six Sigma is a highly structured process aimed at understanding and reducing variation to ensure that the process always delivers the product or service required by the customer. Six Sigma requires statistical evidence and proof of performance, with a mantra of show me the evidence, the ultimate aim of which is to ensure the product delivered is absolutely consistent and within specification. Six Sigma has a bias to understanding the customer and only acting on statistically valid evidence.The aim of both Lean and Six Sigma is to reduce waste, particularly defects, improve process performance and thereby increase customer satisfaction. Lean aims to achieve this by identifying and removing waste and non-value added activities. Six Sigma aims to achieve this by ensuring the customer needs are fully understood and the process is capable of delivering the required product consistently.
- Which Should be used first, Lean or Six Sigma
My perception is that if a practitioner is more comfortable with Lean they will use the lean tools first and if they are more comfortable with Six Sigma they will apply Six Sigma first. Let’s phrase that question differently and see if it still makes sense.
Do you want to reduce waste, defects, and lead time for your process through Lean, or do you want to reduce waste, defects and lead time for your process through Six Sigma? I believe almost every production manager and senior executive would ask one more question; why do I have to choose?
Lean and Six Sigma processes are valuable and there is a strong crossover in the skills. For example if final checking of a process is unnecessarily complicated and yielding too many defects, would you want to be certain that the test method was correctly identifying defects? Of course, therefore we should use Six Sigma first right, because that is where we find Gauge reproducibility and repeatability tools? However, would you want to eat until that was done before simplifying the process? If we give in to the tyranny of “or” we have to choose. What if we choose and instead, and use different groups in the team for both exercises. We need to make sure they communicate effectively, but if the tasks are perceived as of equal importance and we promote a collaborative approach, we can get both done in parallel. That way we eliminate the non-value added steps and ensure that we can separate good parts from bad parts.
If we start with Lean we end up with a simple process (good) without knowing if our output performance is due to the test method, operator or parts (bad). If we start with Six Sigma, we know where the variation finished part performance comes from (good), but the process is still very complicated and we still can’t clearly see what needs to change (bad). If we apply both techniques in parallel we get a simplified process (good) with clarity of process performance (good). Applying both in parallel gives the best results. - Is Lean better than Six Sigma?
Is your car engine more important than the steering? Neither works well without the other, having a car that can go fast, but is hard to direct is not going to work, equally having an excellent capability to direct the car, but nothing to make it move is also going to fail.
Lean and Six Sigma are complementary and whilst each is an excellent tool in it’s own right, when used together these two tools yield results far in excess of what each can give alone. Neither is better than the other, they are different and they are complimentary. Lean or six sigma is not a binary choice, it is a comprehensive toolkit for solving problems.
Just as an engineer uses different tools and techniques for different structures, so Lean and Six Sigma should be applied when the tools and techniques are appropriate to the task in hand.
So my final message on this would be don’t worry about whether the improvement process should be lean or six sigma, instead worry about whether the tool selected to improve the process will yield the most effective solution. In other words don’t get trapped by the tyranny of “or” instead be empowered by the freedom of “and”.
Lean out for low hanging fruit?
What is lean?
So many times when people start implementing lean they focus on so called ‘ low hanging fruit’ but is that all there is to it?
The approach of some practitioners would suggest it is, however there is so much more than just taking ‘low hanging fruit’. Also let us not forget that low hanging fruit is often overripe and may not be the best quality!
So where does this focus on ‘low hanging fruit’ come from?
My perception is the reason for such immediate focus on ‘low hanging fruit’ comes from two things. Firstly, there is an unrealistic expectation of the rate of improvement from process improvement activities. Many senior executives seem to have a very short horizon for improvement, and if money is to be spent on process improvement there must be a return within six months, sometimes within three months. This forces a focus on short term improvements, the so called ‘low hanging fruit’. There is nothing wrong with making these improvements, they are free cash, necessary and failing to address them can be damaging to profitability and performance, but this approach should not be confused with a structured lean implementation.
‘Low hanging fruit’ approaches will deliver short term improvement in both process and financial performance, however this will be unsustainable and will not drive the business to be a time based competitor. It is implicit in the description that these rewards are easy to access and obvious things to do, so what is the difference in lean manufacturing? We are making improvements, reducing costs, its all the same thing isn’t it? Actually, no it isn’t. Making obvious improvements should just be done and requires little or no effort and little skill to achieve. Lean manufacturing should focus the business on time based competition, that is making things faster, more reliably and ultimately this will reduce costs. Notice that lowering costs is one result of lean manufacturing. The real focus in lean manufacturing is superior customer satisfaction through time based competition.
Why is time based competition so important?
Time based competitors have distinct advantages over other competitors since for every quartering of total completion time, they experience a doubling of productivity and reduce costs by 20% At the same time they enjoy three times the growth rate of competitors and double the profit margin. This is achieved through a relentless focus on what is of value to the customer
For a process operator access these benefits, they have to implement a sustained and structured lean manufacturing initiative which addresses the following key features of lean;
- Value
What does the customer value? Without knowing this, how can you ensure that value is added and delivered to the customer? The lean journey is always from the customer perspective, since focusing on this the customer values is the best way to ensure business activities generate a profitable return - Value Stream
Mapping how and when value is added to the product enables the business to focus all efforts on doing things the customer values. Mapping the value stream is about more than just the physical activities, it encompasses all of the information flows, all work in progress, everything required to create and deliver the product and / or service the customer needs - Flow
What is the most efficient way to join two points? A straight line, in the same way it is important that materials flow in one direction through the process. The flow should always be from raw materials to delivery of finished product, with minimal work in progress. - Pull
In an ideal manufacturing environment, materials are pulled through the process by demand from the ‘customer’ rather than having materials pushed into the next process regardless of whether to not they are needed. - Perfection
A continuous improvement approach should be adopted, always looking to create additional value in the process,. this should be done either through incremental changes or through a major step change.
Most ‘low hanging fruit’ is of value from the perspective of the supplier’s costs, not from the perspective of customer value, so whilst it is valuable and important to address these losses, it does not replace a lean manufacturing implementation.
Start with understanding value from the perspective of the customer, map the process as it is (current state VSM), then map the process how you would like it to be (future state VSM). Construct a plan to modify the process from current state to future state, taking into account the financial and personnel resources needed to when declaring a timescale. This is then used as a blueprint for the lean transformation.
Lean is a structured, rigorous, disciplined process requiring dedication, focus and hard work to deliver profound and sustainable improvement in the time based competitiveness of the process, leading to improvements in
- Process cycle time
- Waste
- Lead times
- Customer satisfaction
- Turnover
- Margin.