What is Six Sigma CP Cpk values?
Table of Contents
What is Six Sigma CP Cpk values?
The standard Cpk level is 2.0 for a process in six sigma quality control. The most relevant acceptability levels for Cpk depends on your customer – the Voice of the Customer.
What does a Cpk of 1.33 mean?
In general, the higher the Cpk, the better. A Cpk value less than 1.0 is considered poor and the process is not capable. A value between 1.0 and 1.33 is considered barely capable, and a value greater than 1.33 is considered capable.
How is Cpk calculated in Six Sigma?
The formula for the calculation of Cpk is Cpk = min(USL – μ, μ – LSL) / (3σ) where USL and LSL are the upper and lower specification limits, respectively. A process with a Cpk of 2.0 is considered excellent, while one with a Cpk of 1.33 is considered adequate.
What is Cpk value?
The higher the Cpk, the better is the capability of the process to meet its requirements. In the industry, a Cpk of less than 1.66 needs a closer look. A Cpk that’s less than 1.33 needs some action to make it higher, and a Cpk of less than 1.0 means that the process is not capable of meeting its requirements.
How many standard deviations is 1.33 Cpk?
four standard deviations
Note that Cp = Cpk = 1.33. The sigma level is now 4 – the specification limits are now four standard deviations away from the average.
What does Cpk of 4 mean?
This means the closest spec is 4 standard deviations away from the mean. If staying in spec is critical, then the preferred value is 1.67, meaning the closest spec is 5 standard deviations away. Finally, if the value of Cpk is 2, then the closest spec is 6 standard deviations.
What is Cpk & PPK?
So the key takeaway is that Cpk is the potential of a process to meet a specification (short term) while Ppk is how the process actually did (long term). Another way to look at the difference is that Cpk is used for a subgroup of data, while Ppk is used for the whole process.
What is PPK vs Cpk?
How many sigma is 1.67 Cpk?
5.0
Sigma level table
| Two sided table | ||
|---|---|---|
| Cpk Ppk | Sigma level | % out of tolerance |
| 1.67 | 5.0 | 0.0001 |
| 1.83 | 5.5 | 0.000004 |
| 2.00 | 6.0 | 0.0000002 |
What is CP Cpk and PP PPK?
Cp, Cpk, Pp and Ppk are all parameters (indices) that can help us to understand how our process is operating relative to the specifications, or in other words, they measure how close our process is running to its specification limits. For requirements we measure the process specifications.
