“Good” becomes “better”: Assuring and enhancing quality thanks to “Six Sigma”

Products of outstanding quality, efficient manufacturing methods and well-matched business processes are major prerequisites and guarantors of SGB-SMIT’s success in the market.

In order to be able to serve customers in a better and more reliable fashion, and as competitors do not sit idly by, it is necessary to introduce improvements in all our processes continually.

In the USA in the 1980s, Motorola developed a systematic approach to achieve both process and quality improvement. Motorola operating at that time in the sector of electronics and semi-conductors with high production quantities, they strongly relied on the application of statistical and analytical methods. It is the field of statistics that the designation of this methodology, “Six Sigma” derives from, with Sigma denoting the standard deviation of a probability distribution. Every process is supposed to be conducted with such a degree of reliability as to ensure that the probability of the specified tolerances not being complied with remains sufficiently low even in case of a slight shifting of the mean value (for example due to temperature changes or inaccurately set machines).  Thus, it was defined that the standard deviation of the probability distribution of the process must be six times less than the tolerance, which results in approx. 3 errors per 1,000,000 processes.

Six Sigma

Six Sigma is about reducing variance and about centering, comparable to a marksman for whom a steady hand and appropriate adjustment of the gun sight are vital to enable him to keep hitting the mark. „DMAIC“, the key word in Six Sigma, means Define-Measure-Analyze-Improve-Control. The Six Sigma approach was adopted by other big companies such as General Electric, further developed and completed by methods from “Lean Manufacturing“.

Early in 2016

Handover of the Green Belt Training Certificates to the Production Managers at SMIT in Nijmegen.

... the Business Units SMIT in Nijmegen and Cast-Resin Transformers in Regensburg started to offer employees Six Sigma training courses. In the meantime, various employees have participated in the courses, performed projects and received the appropriate attendance certificate.

It would appear that the requirement concerning only 3 errors in 1 million processes does not make sense, as the SGB-SMIT Group does not manufacture more than approx. 20,000 transformers per year. However, it is easy to guess that production of a transformer does not only require ONE process but a host of processes and components. Assuming that there are 20 such critical processes, each with “Six Sigma” quality, the probability of the transformer not passing the test in the test area is already 0.7 : 10,000. Unfortunately, our everyday production has not yet quite achieved such a failure rate. Assuming a precision of 4 Sigma, 20 processes would already result in 12% failures.

In the meantime, the SGB-SMIT Group has decided to apply the Six Sigma approach throughout the Group. Thus, the Mains Transformer area in Regensburg and SBG in Neumark have started to train employees. Six Sigma features various training levels. Following the belt colors used in the martial art judo to identify a student’s level of training, Six Sigma also uses various levels designated as Yellow Belt, Green Belt, Black Belt, etc.

A Green-Belt Project performed at SMIT dealt with an air bag which is used as a separator between oil and the ambient air in the conservator. In the past, leakages had been detected in isolated cases which might cause the transformer to switch OFF during operation. The reasons for this phenomenon were unclear. Within the project, a number of possible causes were defined and analyzed and the critical issues determined. The fitters are now being trained to ensure that such incidents are ruled out in the future.

Statistical recording of time required for and duration of order preparation.

In the Regensburg Cast-Resin Transformer division, a Green-Belt Project was performed in a completely different area - in Sales. Here again, the DMAIC principle was used and the Six Sigma tools applied. Thanks to the findings obtained, an approach is used in order preparation which permits quicker and more specific responses to customer inquiries.

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