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DMAIC & DMADV
Six Sigma projects follow two project methodologies inspired by Deming's Plan-Do-Check-Act Cycle. These methodologies, composed of five phases each, bear the acronyms DMAIC and DMADV.
DMAIC is used for projects aimed at improving an existing business process.
The DMAIC project methodology has five phases:
Define the problem, the voice of the customer, and the project goals, specifically.
Measure key aspects of the current process and collect relevant data.
Analyze the data to investigate and verify cause-and-effect relationships. Determine what the relationships are, and attempt to ensure that all factors have been considered. Seek out root cause of the defect under investigation.
Improve or optimize the current process based upon data analysis using techniques such as design of experiments, poka yoke or mistake proofing, and standard work to create a new, future state process. Set up pilot runs to establish process capability.
Control the future state process to ensure that any deviations from target are corrected before they result in defects. Implement control systems such as statistical process control, production boards , visual workplaces, and continuously monitor the process.
DMADV is used for projects aimed at creating new product or process designs.
The DMADV project methodology, also known as DFSS ("Design For Six Sigma"),[14] features five phases:
Define design goals that are consistent with customer demands and the enterprise strategy.
Measure and identify CTQs (characteristics that are Critical To Quality), product capabilities, production process capability, and risks.
Analyze to develop and design alternatives, create a high-level design and evaluate design capability to select the best design.
Design details, optimize the design, and plan for design verification. This phase may require simulations.
Verify the design, set up pilot runs, implement the production process and hand it over to the process owner(s).
DMAIC is used for projects aimed at improving an existing business process.
The DMAIC project methodology has five phases:
Define the problem, the voice of the customer, and the project goals, specifically.
Measure key aspects of the current process and collect relevant data.
Analyze the data to investigate and verify cause-and-effect relationships. Determine what the relationships are, and attempt to ensure that all factors have been considered. Seek out root cause of the defect under investigation.
Improve or optimize the current process based upon data analysis using techniques such as design of experiments, poka yoke or mistake proofing, and standard work to create a new, future state process. Set up pilot runs to establish process capability.
Control the future state process to ensure that any deviations from target are corrected before they result in defects. Implement control systems such as statistical process control, production boards , visual workplaces, and continuously monitor the process.
DMADV is used for projects aimed at creating new product or process designs.
The DMADV project methodology, also known as DFSS ("Design For Six Sigma"),[14] features five phases:
Define design goals that are consistent with customer demands and the enterprise strategy.
Measure and identify CTQs (characteristics that are Critical To Quality), product capabilities, production process capability, and risks.
Analyze to develop and design alternatives, create a high-level design and evaluate design capability to select the best design.
Design details, optimize the design, and plan for design verification. This phase may require simulations.
Verify the design, set up pilot runs, implement the production process and hand it over to the process owner(s).
Origin of Term Six Sigma
The term Six Sigma originated from terminology associated with manufacturing, specifically terms associated with statistical modeling of manufacturing processes. The maturity of a manufacturing process can be described by a sigma rating indicating its yield, or the percentage of defect-free products it creates. A six sigma process is one in which 99.99966% of the products manufactured are statistically expected to be free of defects (3.4 defects per million) [DPMO : Defects Per Million Opportunities]. Motorola set a goal of "six sigma" for all of its manufacturing operations, and this goal became a byword for the management and engineering practices used to achieve it.
Six Sigma measures defects in million ‘opportunities’ and assigns ‘levels’. There are six such levels. An organizations is said to be at 6 sigma level if it has 3.4 defects per million opportunities. This is the highest level an organization can attain. Average American company is at 4 sigma level. That is equivalent to 6,210 defects per million opportunities.
Six Sigma seeks to improve the quality of process outputs by identifying and removing the causes of defects (errors) and minimizing variability in manufacturing and business processes. It uses a set of quality management methods, including statistical methods, and creates a special infrastructure of people within the organization ("Black Belts", "Green Belts", etc.) who are experts in these methods. Each Six Sigma project carried out within an organization follows a defined sequence of steps and has quantified financial targets (cost reduction or profit increase).
Six Sigma measures defects in million ‘opportunities’ and assigns ‘levels’. There are six such levels. An organizations is said to be at 6 sigma level if it has 3.4 defects per million opportunities. This is the highest level an organization can attain. Average American company is at 4 sigma level. That is equivalent to 6,210 defects per million opportunities.
Six Sigma seeks to improve the quality of process outputs by identifying and removing the causes of defects (errors) and minimizing variability in manufacturing and business processes. It uses a set of quality management methods, including statistical methods, and creates a special infrastructure of people within the organization ("Black Belts", "Green Belts", etc.) who are experts in these methods. Each Six Sigma project carried out within an organization follows a defined sequence of steps and has quantified financial targets (cost reduction or profit increase).
| Sigma level | DPMO | Percent defective | Percentage yield | Short-term Cpk | Long-term Cpk |
|---|---|---|---|---|---|
| 1 | 691,462 | 69% | 31% | 0.33 | –0.17 |
| 2 | 308,538 | 31% | 69% | 0.67 | 0.17 |
| 3 | 66,807 | 6.7% | 93.3% | 1.00 | 0.5 |
| 4 | 6,210 | 0.62% | 99.38% | 1.33 | 0.83 |
| 5 | 233 | 0.023% | 99.977% | 1.67 | 1.17 |
| 6 | 3.4 | 0.00034% | 99.99966% | 2.00 | 1.5 |
| 7 | 0.019 | 0.0000019% | 99.9999981% | 2.33 | 1.83 |
Tuesday, July 12, 2011
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