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Six sigma is not only about Statistics

Lots of Organizations and people are under the impression that Six sigma is a statistical method to drive improvement in the companies. This wrong notion is due to the way heavy statistics is used in doing projects. From my manufacturing experience, i can say that if one is not technically sound and experienced in the processes, we cannot solve problems and do improvements just by knowing the tools.


Let us take an example of a problem in a manufacturing organization, recently taken up for solving under Six sigma initiative. Refer the picture below for illustration

The problem we had taken to solve is Friction welding Joint failure. The incidence of this failures were very less with 1-3 failures happening every month. In terms of ppm, this is about 500 ppm. Now, if we have to crack this problem using Six sigma methodology, firstly we should definitely know the Science of Friction welding, like how the heat is generated and how the fusion happens between the two dissimilar metals. Without this knowledge we will not be in a position to identify clearly the suspected operational causes that can lead to the failure. Hence, one of the first and foremost requirement before we dive into the analysis phase in Six sigma is to clearly understand the Scientific reason for the problem and clearly understand the science of the process. It is not that we will be knowing the fundamental Science for every problem or project we do. But with continuous questioning, observation and efforts one can easily understand the science of the problem and this is very much required before we start doing the analysis


For the above problem, once we understood clearly on how the process works, how heat is generated, how fusion happens, then we were able to clearly connect the parameters and reasons that could lead to poor heat generation or poor fusion. This helped us in doing the analysis for the right suspected causes , instead of shooting in dark.


So the key take away which i had learnt in many such projects, is we should clearly understand the science of the problem and the process before we do further analysis and we should change our mindset that Six sigma is only about statistics and data analysis.

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