Six Sigma is a quality management philosophy that focuses on reducing variation, measuring defects, and improving quality. Traditional quality programs (such as TQM) define a process as capable if the process’s natural spread, plus and minus three sigma, was less than the engineering tolerance. + 3 sigma provides 0.00135 in each tail, or 0.00270 in the two tales, so, in 1 million parts, 2700 would be defective. However, six Sigma requires that processes operate such that the nearest engineering requirement is at least six sigma from the process mean. Under six sigma, the expected non-conformances are 0.002 PPM (2 parts-per-billion, or PPB). It should be noted that Six Sigma literature often states that a process operating at six sigma will produce 3.4 parts-per-million (PPM) non conformances. This is because it is presumed that the process mean can drift 1.5 sigma in either direction.

Finally, six sigma can be used in any industry and sector including electric vehicles.

Ayman Abdallah, nailed it on what a general overview of Six Sigma. Another key is that management and everyone is on board to implement Six Sigma for it to succeed.

Ayman Bahjat Abdallah and Mark Aceves Sr.

Six Sima (SS) in general cannot be helpful for management of electric vehicles or any vehicles or complex processes at all.

Six Sigma (SS) foundations are flawed. For example, SS pushes 3.4 ppm defect target rate that is included in numerous SS articles and books. But this figure is simply the area under the normal distribution curve that corresponds to 4.5 sigma, which is the unsubstantiated shift 1.5 sigma from the claimed 6 sigma level.

Many SS claims are based on properties of tails of normal distribution that is a poor model for the majority of real processes anyway because it is the 2-way unbounded symmetrical distribution.

The DMAIC process that SS claims as its novel approach to structural problem solving is being used in some forms for centuries in any reputable research since Roger Bacon time, i.e. define the problem, measure the effect under study using a reliable measurement system, analyze the data, suggest independent testing and control results.

Thus, SS is nothing more than a combination of naive statistics based on properties of normal distribution and some general slogans for voice of customers (VOC) and stakeholder management. SS cannot offer real quantitative root cause analysis and improvement methods. Design of experiments (DOE) included in Analysis and Improve phase are of limited use for relatively small scale lab experiments.

No powerful methodologies such as computer modeling and simulation, mathematical analysis and calculus are a part of SS standard 'tool box'.

Personally I am twice certified SS Black Belt (from General Electric, GE). Therefore, I know this stuff from inside. I vividly remember how 'infamous' GE CEO Jack Welch pushed SS into GE by his iron hand, creating a huge new bureaucracy of poorly educated Belt Belts, Master BB, quality champions, etc. I remember how very good engineers were fired for dissenting to SS because they rightly advocated for a wide use of mathematics and modeling for design improvement rather than relying on laughable SS claims and 'tools'.

By the way, look at the current sorry state and the rolling down stock price of the once mighty GE company. The same for 3M and many other companies that tried to follow the 'leaders' (GE, Motorola, 3M, et al) in pushing in six sigma programs spending millions and millions $$$ for formal training and numerous high paid consultants....

Alexander Kolker

Thank you for your information. I always have an open mind from a different perspective and experience.

You have made a good point and I understand. I have seen Six Sigma succeed and fail personally in two different companies. One company used Six Sigma and was able to get one of their plants fully lights out in production. Then a medical company I worked for tried, even had a representative helping management but it failed and It created lower output and efficiency in production.

I am only green belt certified and have seen how great it sounds in the classroom but how trying to implement in many areas fail in the production floor.

As a former Six Sigma Master for a US defense contractor and currently the EV Sherpa for an electric utility in Texas, I think I have a different perspective than Mark and Alexander. Six Sigma is an engineering philosophy. The mistake most companies have made is to believe it is the secret sauce to ensure highest quality products. I wrote a book, the Six Sigma Path to Leadership in which I wrote a chapter entitled "The Myth of Six Sigma Cost Avoidance Measurement." Companies went to Wall Street to tout the billions of dollars saved by applying Six Sigma to all of their products and programs. The inability to establish with certainty the cost that would have been incurred makes it impossible to say how much less the actual cost is. That aside, Six Sigma principles, incorporating good engineering practices, as Alexander points out, can definitely deliver improved products. My perception is that Ashish's question is how can Six Sigma or any disciplined application of fundamental engineering tools and practices improve the management of electric vehicles. The answer is the same as it applies to any vehicle management program. Fleet vehicles now capture a significant amount of data. The more advanced EVs like Tesla do as well. We are using engineering tools and practices to understand the electric load shapes emerging on electric feeders as a result of EV owners charging their vehicles at home. We are looking at the impact of large class 8 truck charging for distribution center depots and the electric charging requirements and practices for bus fleets. So the answer is Six Sigma can be an effective approach to learn how to manage EV charging and EV fleets in addition to the quality aspect of building a six sigma car that minimizes defects.

Article A novel approach to lean six sigma project management: a con...

Refer the above link.

I would add it might be helpful in studying the charging and discharginging processes of the EV. It might also be helpful in studing the various assembly and manufacturing processes in making an EV and minimizing defects in those processes