Question: What Is The Maximum Value Of CP And CPK?

What is CPK and how is it 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 the CPK for 3 sigma?

Relationship to measures of process falloutCpkAdjusted Sigma level (σ)Process yield1.00393.32%1.33499.38%1.67599.9767%2.00699.99966%2 more rows

Can CP be greater than CPK?

When the Cpk is greater than or equal to one, the process is considered capable of producing a product within specification limits. … The Cpk index can never be greater than the Cp, only equal to it. This happens when the actual process average falls in the middle of the specification limits.

What does a Cpk of 0 mean?

No problemMean = 0: No problem. You can calculate Cp and Cpk as you allways do. … This would mean that youe process has no variation, and there is no such a process.

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.

Why CP value is greater than CPK?

So this is how Cp and Cpk work together: When the values are similar, the mean is close to the middle of the specification limits. When Cp is greater than Cpk, the mean is nearer to one specification limit or the other.

What does CPK stand for?

creatine phosphokinaseCPK is the abbreviation for a blood test called creatine phosphokinase. CPK is an enzyme found primarily in muscles. This includes the muscles in the heart. Any muscle injury or damage can cause a rise in the blood level of CPK.

What is a high level of CPK?

When the total CPK level is very high, it most often means there has been injury or stress to muscle tissue, the heart, or the brain. Muscle tissue injury is most likely. When a muscle is damaged, CPK leaks into the bloodstream. Finding which specific form of CPK is high helps determine which tissue has been damaged.

What is a normal CPK level?

CPK blood tests the different forms of CPK in the bloodstream and the CPK normal range varies from a male to female. The CPK normal range for a male is between 39 – 308 U/L, while in females the CPK normal range is between 26 – 192 U/L.

What is the maximum Cpk value?

1.0The 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.

What is a good Cp and 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.

How many Sigma is 1.67 Cpk?

6 sigmaCp = Cpk = 1.67. The sigma level is now 5 – the specifications are five standard deviations away from the average. The out of specification has decreased to 0.57 ppm. The fourth curve represents that magical 6 sigma level.

What is CP CPK value?

Cp and Cpk, commonly referred to as process capability indices, are used to define the ability of a process to produce a product that meets requirements. … Specifications are normally defined in terms of nominal (+/-) tolerances or ranges (low to high.

Can CP CPK be negative?

Both Cpk and Ppk can be a negative numbers. It means that, on average, the process is not meeting customer requirements.

What is a good CPK?

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 a Cp of 1.5 mean?

A Cp of less than one indicates that the process spread is greater than the specification. This means that some of the data lies outside the specification. … So a Cp of 1.5 means the process can fit inside the specification 1.5 times. A Cp greater than one is obviously desirable.

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)

How many ppm is 1.33 Cpk?

Sigma level tableTwo sided tableCpk PpkSigma levelPPM out of tolerance1.173.5465.2581.334.063.3421.504.56.7958 more rows

How can I increase 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 percentage is 4 sigma?

Five-sigma corresponds to a p-value, or probability, of 3×10-7, or about 1 in 3.5 million….Don’t be so sure.σConfidence that result is real3 σ99.87%3.5 σ99.98%> 4 σ100% (almost)4 more rows•Aug 16, 2017