Six Sigma

Six Sigma is a set of tools and techniques to improve the process of work. Motorola in 1986 develop this Six Sigma techniques. It was made by Jack Welch for his company General Electric in 1995 to improve the quality of work.

Six sigma improve the quality of process by identifying and discarding the causes of errors and minimizing the variability in business processes. It uses set of methods that are quality management, statistical methods that create Champions, Black Belts, Green Belts, Yellow Belts people within the organizations that are experts in their field.

Six Sigma project carried out within the organization that follows a sequence of steps with the set target. These targets can be to reduce cycle time, increase customer satisfaction, to reduce cost and to increase profit.

Term Six Sigma was originated from terminology associated with manufacturing, specifically with statistical modeling of manufacturing processes.  The manufacturing process that create defect-free products can be described by a sigma rating. And, a six sigma process is that in which 99.99966% of the products manufactured are expected to be defect-free.

Six Sigma projects follow two major project methodologies that was inspired by Deming's Plan-Do-Check-Act Cycle. These methodologies are DMAIC and DMADV. DMAIC is used for improving an existing business process where as DMADV is used for projects that create new products of process designs.



This methodology consists of five phases that are:

  • D-Define the system, the project goals and the voice of the customer and their requirements.


  • M-Measure the aspects of current process and collect the data required.


  • A-Analyze the data to investigate and verify the defect. To seek out root cause of the defect under investigation.


  • I-Improve the current process based upon data analysis using various techniques such as design of experiment, mistake proofing or Poka voke, and set up pilot runs to establish process capability.

  • C-Control the future state process to ensure that if there is any defect, it can be corrected before the end of the process. This is done by continuously monitoring the process, visual workplaces, production boards, etc.


The DMADV project methodology also called as DFSS (Design For Six Sigma) features five phases:

  • D-Define goals that are consistent with customer demands and strategy.


  • M-Measure and identify product capabilities, risks, production process capability and CTQs (Critical To Quality).


  • A-Analyze to design and develop alternatives.


  • D-Design an improved alternative after analyzing the best alternative.


  • V-Verify the design, implement the production process and hand it over to the process owner.

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