A bad sigma level is generally considered to be anything below 3 sigma. This means that a process with a sigma level below 3 has a high probability of producing defects.
Here's a breakdown:
- Sigma level is a measure of how much variation there is in a process.
- Higher sigma levels indicate less variation and fewer defects.
- Lower sigma levels indicate more variation and more defects.
Why is a Sigma Level Below 3 Considered Bad?
A sigma level below 3 means that the process is not very consistent and is likely to produce a significant number of defects. For example, a process with a 2 sigma level will produce around 300 defects per million opportunities, while a process with a 1 sigma level will produce around 690,000 defects per million opportunities.
What Can Be Done to Improve a Bad Sigma Level?
- Identify the root causes of variation.
- Implement process improvements to reduce variation.
- Train employees on proper procedures.
- Use statistical process control (SPC) to monitor the process.
By taking these steps, you can improve the consistency of your processes and reduce the number of defects.
