DMAIC and DMADV

DMAIC - Define - Measure - Analyze - Improve - Control

DMAIC is a structured and repeated process improvement methodology, which focuses on defects reduction and helps improve existing products and processes. DMAIC is a defect reduction strategy.

DMADV - Define - Measure - Analyze - Design - Verify

Unlike DMAIC, DMADV is for develop / re-designing new products/processes. DMADV focusses on preventing errors and defects.

How smart customers quiz companies claiming 6sigma certification...

1. Which processes of your company are at six sigma level?
2. What are the specification limits of those processes? (Note that spec limits are set by the customer, while UCL and LCL are 3 times the standard deviation)
3. Is your company willing to take penalty for defects?

Companies are NOT certified Six Sigma...their processes are...

Companies are not certified six sigma, their processes could be at six sigma level. Implementation, monitoring and control of six sigma are all done within the company implementing the six sigma program. No one outside comes and inspects it.

Companies focus on critical processes (as per VOC /VOB) and then take them to levels of six sigma efficiency.

Mistake proofing...

Mistake proofing is when you take precautions to ensure that there is no possibility of error occurring. In England, it was found that people mistook between petrol and diesel fillers while fueling their cars at gas stations. (They have to fill it by themselves) . Manned gas stations did not solve the problem completely because there was always the possibility of human failure. Ultimately the car manufacturers fitted the petrol cars with positive polarity fuel tank mouth, and diesel cars with negative polarity. The gas stations had exactly the opposite polarity - petrol dispensers were fitted with negative polarity, and diesels dispensers with positive polarity. (Like charges repel, unlike attract!!!).

DPMO View

What is the need to view defects "per million", can % view not suffice?

Defects per million gives a better insight into defect severity. This magnifies defects and makes the performance look better (if the process is efficient). For example, you can talk that your process has only 1% defects. When talking in terms of percentage, the severity of defects does not seem much. Defects look manageable!!!

Parts per million magnifies the defects and shows a more realistic picture. When translated to PPM, 1% is equal to 10, 000 defects per million! Now this seems too big a value to neglect.

Instead of PPM, a better way to denote variation is by calling points as defects. Thus, we have DPMO (Defects per million opportunities) instead of PPM.