Six Sigma is a systematic approach to reducing variations and improving processes in all sorts of environments, particularly in manufacturing. What is Six Sigma for manufacturing and its main goals and benefits? Let’s explore this tool in more detail here…
What is six sigma?
Here’s the Six Sigma definition from Wikipedia:
Six Sigma (6σ) is a set of techniques and tools for process improvement.
Six Sigma strategies seek to improve manufacturing quality by identifying and removing the causes of defects and minimizing variability in manufacturing and business processes. This is done by using empirical and statistical quality management methods and by hiring people who serve as Six Sigma experts. Each Six Sigma project follows a defined methodology and has specific value targets, such as reducing pollution or increasing customer satisfaction.
If you find something that is not consistent and is an unwelcome variation, like a product defect, for example, you can use the six sigma process to identify and fix those issues. In electronics manufacturing, for example, typically Six Sigma is used to control a variation in response to the defect rate. So you’re trying to reduce the defect rate by reducing the variation. This approach is great for improving quality and customer satisfaction by reducing defects they’re likely to suffer from when purchasing products.
The good news is that Six Sigma can be used to find out why something happened somewhere in most manufacturing companies. The issue could be process-related, design-related, or manufacturing-related, for example.
Suppose it proves particularly difficult to find the root cause of the issue through a traditional root cause analysis. In that case, six sigma is a good next port of call because it’s probably one of the deepest analyses used to figure out what happened. During the six sigma process, you find variation and then you have to minimize and control it somehow, and that’s when you finally resolve the problem.
Its main goal
The Bryant & Stratton college state:
The main goal of any Six Sigma implementation is quality improvement. The term originally comes from the sigma rating used to statistically rate manufacturing processes in engineering. A six sigma process occurs when no defects are expected in 99.99966% of all chances to produce them. This is the goal of any Six Sigma implementation.
It focuses on the use of statistical improvements to minimize defects in products and services.
Six Sigma vs Lean manufacturing
Six sigma is often confused with lean manufacturing, but the latter is more specific to production processes alone. Let’s explore Six Sigma vs Lean manufacturing:
Six Sigma
Six Sigma also has five steps for improving an existing process, product, or service called DMAIC: Define, Measure, Analyze, Improve, and Control & monitor. On the other hand, they have DMADV: Define, Measure, Analyze, Design, Verify for a new process, product, or service.
Each one of these is a big step in terms of how you take your product, the issue, the process, and how you analyze them. As you can see, Six Sigma is a more flexible problem-solving skill than Lean manufacturing and can be used in many circumstances, not only in production.
Let’s explore the two Six Sigma tools, DMAIC vs DMADV:
DMAIC (problem-solving in existing situations)
- In the first phase, Define, that’s where you actually define the project scope and determine what the team objectives are. That also means defining your team members’ roles and so on.
- Measure is when you’re measuring the scope and you’re trying to understand what needs to be measured. It could be a specification, the scope of the issue, the defect rate, etc. Somehow you need to measure the scope of the issues.
- Analyze occurs after you have all this data and need to analyze it and come up with a way of determination about what actions you must take, who will take the actions, and how they’re distributed among the teams.
- Improve means the actions that were taken to improve the variation based on the different team members involved will be tracked to see how they improved the process. It’s tested and we finally see that we have a process that works to correct the variation.
- Control and monitor is the final step after we know that the process worked as intended and now we need to control and monitor it to make sure that it’s going to stay that way. You put a mechanism of checks and balances in place so that it keeps checking the process and making sure that it is going to stay in control as it was meant to.
On the other hand, if a new process needs to be created and implemented, then another approach is required:
DMADV (when a new process needs to be created)
Instead of DMAIC which is used for improving existing processes, DMADV will be used if improvements aren’t possible and a new process, for example, needs to be created. We commonly use this approach for our clients’ new product introduction projects. It also includes 5 steps:
- Define the purpose of the process, product, or service, and the project scope.
- Measure is where we decide what will be measured in the process or product.
- Analyze the data that comes from the measurement and decide on what process should be used to replace the current one that has issues.
- Design the new process, product, or service, and test it. For products, prototypes may be made, for software, an early build, and for processes, a test process where bugs will be ironed out.
- Verify if the new approach works via testing, simulating, and/or pilot runs.
Lean Manufacturing
Lean manufacturing actually uses a five-step process for continuous improvement and the ability to refine a manufacturing process to become more efficient and eliminate common wastes:
- Value: What’s the value here? Defining this helps target improvement efforts and may be driven by your or your customer’s requirements.
- The Value Stream: Identify the value stream which is the process flow of materials in the factory from start to finish and quantify the time and volume taken at each step, this will probably be in the form of a flow chart.
- Flow: Make the process flow continuously by identifying and removing barriers that slow it down.
- Pull: Introduce pull (the process is driven by customer demand when required as opposed to manufacturing and building up inventory regardless of demand) between each step of the process rather than
- Perfection: Keep refining the process continually so that the number of steps and time and materials required keeps being reduced over time.
The continuous improvement process is like a loop where we keep following the manufacturing process and finding and improving something every time. Remember, Lean manufacturing is specifically focused on production and can’t be applied in every situation.
Who invented Six Sigma?
Six sigma is a statistical process that was invented by a Motorola engineer, Bill Smith, in 1986. It was later registered as a trademark in the 90s and billions of dollars of savings have been attributed to it by some of the world’s leading businesses, such as Motorola themselves.
Who has benefited?
Motorola supposedly saved around US$17 billion through implementing Six Sigma projects to reduce issues and waste. Similarly, the USDA, Boeing, GE, and Microsoft are also high-profile businesses and organizations who have saved billions.
GE’s exciting results from implementing Six Sigma for manufacturing
In former CEO Jack Welch’s book: Jack: Straight from the Gut, he outlines the positive effect that implementing Six Sigma had on the business in the 90s.
It allowed [GE] to get new business from customers like Sony.
To reap the full benefits and to achieve customer satisfaction, they found they had to measure their performance (particularly in terms of lead time) from the customer’s eyes, which was not something the Six Sigma literature mentioned.After the first year, GE started to use the statistical tools of Six Sigma to improve the development of new products, with even greater results.
For example, an issue with gas turbines was rotors cracking due to vibrations – they reduced vibrations by 300% and improved uptime dramatically.
All of GE’s medical division’s new products were designed with the use of Six Sigma for a period of time.In 1998, GE’s analyses estimated they earned 750 million dollars in extra profit that year thanks to the Six Sigma implementation.
While it is possible that by applying the typical Quality process improvement techniques perhaps a lot would have been improved anyway, where Six Sigma becomes effective is that it trains the minds of people to think about problem-solving and how to think of ways to keep improving on a day-to-day basis until there are almost no defects whatsoever.
I found the Six Sigma process to be more effective when you have non-standard processes with major variations that produced poor results. However, in my opinion, in today’s world where the work pace is much faster than it was in GE’s time and customer awareness of quality is much higher than in those days; the application of Six Sigma in every single process may not be very efficient. It takes a team time and a lot of effort to correctly apply Six Sigma methodologies.
However, I still believe that individuals within an organisation who have the six sigma skills, have another tool to solve problems related to variations and drive continuous improvement and reductions in the defects rate.
Six Sigma belts for practitioners
Companies who see the benefit of implementing a Six Sigma process to control variation need to use talent to implement and train Six Sigma. Consultants can come in to train staff and they will achieve a certification (Six Sigma belt); or, if you have an in-house expert, they may do the training instead.
The level of certification is given a ‘belt color’ and each of the Six Sigma belts corresponds to a different level of knowledge and practice:
- White Belt: You must complete several hours of training and understand the basics.
- Yellow Belt: You will have done 10 to 15 hours training and be proficient in pulling together data, creating process maps, and more.
- Green Belt: These staff are able to carry out most of the Six Sigma projects for a company. They commonly spend a good part of their time at work on such projects and can pass on their experience to the team.
- Black Belt: Holders of this certification tend to do most of their work on Six Sigma projects. This can only be gained when the staff member has successfully implemented at least two projects in practice, as well as demonstrated a detailed understanding of the process, and passed an examination. They will likely be involved in training.
- Master Black Belt: This is the top rank. Typically they will have 5+ years of experience at Black Belt level and will have successfully implemented at least 10 projects. They will often manage a company’s Six Sigma projects and answer to management, or perhaps they work as a consultant coming in to provide specialist training on a professional basis.
Benefits of Six Sigma
The main benefits of Six Sigma are that you will really decrease waste and increase efficiency, as well as reduce mistakes and errors on, for example, an assembly line. In turn this will decrease your company’s legal risks from unsafe products, and improve customer satisfaction and reduce the return rate because better quality products will make it into the field.
Typical manufacturing benefits to be expected from a well-implemented Six Sigma campaign are:
- Improved efficiency: Resources are utilized to their maximum, so. nothing is wasted.
- Waste is reduced: Processes are optimized with a focus on reducing waste, specifically resources, time, and money.
- Fewer quality issues: The process finds and fixes problems in the design or production process that can lead to quality issues that result in scrap or returns once products have been manufactured.
- Customer satisfaction is improved: The risks of customers receiving products that are poor quality, unreliable, or unsafe are reduced. Therefore, customers have a more positive view of your brand.
- Legal risks are reduced: If products are safer, the likelihood of litigation is less.
- Your profits increase: Less waste and more efficient processes mean that ‘commonly hidden costs’ like scrap and rework are reduced.
Now you have an overview of each tool and can see the difference between Six Sigma vs Lean manufacturing. These are powerful problem-solving tools that are data-driven.
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