Quick Answer: What Does A Cpk Of 1.33 Mean?

Can CPK be negative?

What does a negative Cpk or Ppk Indicate.

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..

Why is it called 6 Sigma?

“Six Sigma” comes from the bell curve used in statistics, where one Sigma symbolizes a single standard deviation from the mean. If the process has six Sigmas, three above and three below the mean, the defect rate is classified as “extremely low.”

What is the maximum value of CPK?

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 diseases cause elevated CPK?

High CPK levels may be seen in people who have:Brain injury or stroke.Convulsions.Delirium tremens.Dermatomyositis or polymyositis.Electric shock.Heart attack.Inflammation of the heart muscle (myocarditis)Lung tissue death (pulmonary infarction)More items…

What is 1 ppm equal to?

1 milligramOne ppm is equivalent to 1 milligram of something per liter of water (mg/l) or 1 milligram of something per kilogram soil (mg/kg).

Why Six Sigma means 3.4 defects?

The objective of Six Sigma quality is to reduce process output variation so that on a long term basis, which is the customer’s aggregate experience with our process over time, this will result in no more than 3.4 defect parts per million (PPM) opportunities (or 3.4 defects per million opportunities – DPMO).

What is the PPM for 1.33 CPK?

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

What does CPK mean?

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 good CP and CPK?

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.

What does a negative CPK indicate?

The process mean is closer to the lower specificationExplanation: A negative Cpk is an indication that the process mean has drifted over either the upper specification or the lower one. It is not a math error, however it could be. It is impossible to have a negative 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)

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.

What happens if CPK is high?

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 CPK normal range?

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 does a Cpk of 0 mean?

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

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.

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 is CP CPK formula?

The equation for Cpk is more complicated: [minimum(mean – LSL, USL – mean)] / (0.5*NT). LSL stands for Lower Specification Limit and USL stands for Upper Specification Limit. Often we describe Cpk as the capability the process is achieving whether or not the mean is centered between the specification limits.

How do you do CPK?

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.