What Is A Good CP And CPK?

Why is it called 6 Sigma?

The etymology is based on the Greek symbol “sigma” or “σ,” a statistical term for measuring process deviation from the process mean or target.

“Six Sigma” comes from the bell curve used in statistics, where one Sigma symbolizes a single standard deviation from the mean..

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.

How is CP calculated?

The CP (“combat power”) is calculated based off the Pokémon species’ base values, the power up level, and three hidden numbers called “IVs” (individual values.) … The higher your Trainer Level is, the more you can power up a Pokémon.

What is CP and CPK in SPC chart?

Capability (Cp) and performance (Cpk) charts illustrate a process’s ability to meet specifications. Although SPC control charts can reveal whether a process is stable, they do not indicate whether the process is capable of producing acceptable output—and whether it is performing to capability.

What if CP is higher 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 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.

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 is a good CP value?

By convention, when a process has a Cp value less than 1.0, it is considered potentially incapable of meeting specification requirements. Conversely, when a process Cp is greater than or equal to 1.0, the process has the potential of being capable. Ideally, the Cp should be as high as possible.

Can CP CPK be negative?

Yes, it is possible for Cpk and Ppk to be negative. Let’s look at the equation – for simplicity we will use the Ppk. 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 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 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).

How do you know if a process is capable?

All the data points fall well within the specification limits with a normal distribution. A process where almost all the measurements fall inside the specification limits is deemed a capable process.

What does CP and CPK tell you?

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. In other words, they define what is expected from an item for it to be usable. …

What does a Cp of 1.33 mean?

Process capability indexProcess capability index (Cpk) is a statistical tool, to measure the ability of a process to produce output within customer’s specification limits. … Cpk = or >1.33 indicates that the process is capable and meets specification limits.

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 Cpk of 2 mean?

When Cpk is negative it means that a process will produce output that is outside the customer specification limits. … 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.

What is difference between CP and PP?

The biggest difference between Cp and Pp is how the Standard Deviation is determined. Pp we use sampling and have to calculate an estimated standard deviation of the sample. In Cp we are assuming a stable process and will likely have enough data to calculate a true standard deviation.

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 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