Quick Answer: What Is A Good CPK?

What does a Cpk of 1.33 mean?

Cpk = or >1.33 indicates that the process is capable and meets specification limits.

Any value less than this may mean variation is too wide compared to the specification or the process average is away from the target..

How many Sigma is 1.67 Cpk?

Sigma level tableTwo sided tableCpk PpkSigma levelPPM out of tolerance1.334.063.3421.504.56.7951.675.00.5738 more rows

How can I raise my CPK levels?

Q: How can we improve Cpk? A: Reduce the variation, while maintaining the same average. Example 3: The analysis for Diameter 3 has a Cp = 0.43 and Cpk = -0.23. Because Cp is bad, we know there’s too much variation.

What is a good CP CPK value?

We generally want a Cpk of at least 1.33 [4 sigma] or higher to satisfy most customers. Cpk can have an upper and lower value reported. If the upper value is 2 and the lower is 1, we say it has been shifted to the left. This tells us nothing about if the process is stable or not.

What does a Cpk of 1.67 mean?

The Capability Index, Cpk. The outcome of a Process Capability study is a single metric, which provides an indication of the ability of a process to consistently provide output which is within required specifications. CPK <1.00 (Poor, incapable) 1.00< CPK <1.67 (Fair) CPK >1.67 (Excellent, Capable)

What does a Cpk of 2.0 mean?

process capability indexThe process capability index, or Cpk, measures a process’s ability to create product within specification limits. … When the Cpk is greater than or equal to one, the process is considered capable of producing a product within specification limits. In a Six Sigma process, the Cpk equals 2.0.

How is CPK calculated?

Cpk is a process capability index used to measure what a process is capable of producing. … 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.

What is minimum Cpk value?

The minimum value of “k” is 0 and the maximum is 1.0. A perfectly centered process will have Cp = Cpk. Both Cpk and Ppk relate the standard deviation and centering of the process about the midpoint to the allowable tolerance specifications. An estimate for Cpk = Cp(1-k).

Is higher CPK better?

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.

What does CPK stand for?

Creatine phosphokinaseCreatine phosphokinase (CPK) is an enzyme in the body. It is found mainly in the heart, brain, and skeletal muscle.

Can CPK be negative?

Yes, it is possible for Cpk and Ppk to be negative. … It is impossible to have a standard deviation be negative so that would mean that x(bar) was larger that the Specification Limit. In other words, the process average is out of specification.

What does high Cpk mean?

Location, Location, LocationCpk: Location, Location, Location! When the distance from the mean to the nearest specification limit is considerably greater than the one-sided process spread, Cpk is high. When the distance from the mean to the nearest specification limit is less than the one-sided process spread, Cpk is low.