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Calculation
a) Standard Deviation (s) is calculated as follows:
√∑(X - Xi)2
n-1
For bilateral tolerances:
i) Capability Index (Cp) = USL - LSL / 6s
ii) Performance Index or Centering of Process (CmK) =
Minimum of USL- X or X - LSL
3s 3s
For single sided tolerances:
i) Performance Index or Centering of Process (CpK) =
a) Find out minimum observed value from the data values.
b) Find out Z = X - Minimum Observed Value
s
c) Corresponding to the arrived value of 'Z' above, choose the value of 'k' from Table given in Annexure-I.
d) Find out CmK = USL - X or X - LSL
ks ks
as the case may be.
USL for runout, roundness, surface finish etc.
LSL for Min. Hardness
M.Ananthakrishnan
What else can I help you with?
What is the definition of Cp and Cpk in Statistical process control?
Cp is the capability of a process and Cpk is the actual capability of a part running in the process. The only way Cp = Cpk is if the process mean is exactly centered which is seldom the case in manufacturing. Therefore, Cp > or = to Cpk.
What does the letters cpk stand for in 6 sigma?
In Six Sigma, the letters "CpK" stand for "Process Capability Index." It is a statistical measure that evaluates how well a process can produce output within specified limits. CpK specifically considers both the process variation and how centered the process is relative to the target specification, providing insight into the capability of the process to meet quality standards. A higher CpK value indicates a more capable process.
Relation between control limits and specification limits?
There is no direct relationship between control limits and specification limits. By saying that I mean that one measure has no effect on the other. However, the comparison of these two ranges can tell you a lot about your ability to meet specification. These terms are most often used, and are thus easiest to explain, in terms of manufacturing a part. Let us assume that we need to cut a piece of metal bar to a length of one inch. Specification limits tell us what variance is acceptable, either to us or our customer, when we produce the said part. The request for such a part would be accompanied by tolerances and might look something like 1.00" +/- 0.005". This means a part that is between 0.995" and 1.005" in length would be considered acceptable. The two acceptable extremes just cited would be our spec limits. Subtracting one from the other we arrive at a spec width of 0.010". Now, control limits are strictly a function of the natural variation of the process in question and are calculated using the measured standard deviation of that process. If the control limits fall inside the spec width, let us say we have an LCL of 0.998" and an UCL of 1.002" for our example, then we have process that is very capable of producing in spec parts almost every time. However, if the control limits fall outside the spec limits, maybe 0.990" and 1.010", then the natural variation present in our process causes us to make many parts that will not fall within the required specification. In other words, the process is not capable. The question about the relationship between spec limits and control limits really comes down to a question about process capability. This was just the briefest of intros to the subject. I suggest further reading (or googling) on the subject of capability (Cp &Cpk).
Why not to calculate Cp for unilateral tolerance?
Calculating Cp for unilateral tolerance is not advisable because Cp assumes a symmetrical distribution of measurements around the target value, which is not the case with unilateral tolerances. Unilateral tolerances only allow variation in one direction (either upper or lower), leading to a lack of symmetry and potential underestimation of process capability. This can result in misleading conclusions about the process's ability to meet specifications, as it does not account for the increased risk of nonconformance. Therefore, alternative metrics, like Cpk, which consider the mean and variability in relation to the specific tolerance limits, are more appropriate for unilateral tolerances.
List of abbreviation for 'Cpk'?
Cpk = Cp (Process Capability) + p (katayori) Japanese for deviation. Cpk = Deviation of process capability
What does the medical abbreviation CPK mean?
CPK means creatine phosphokinase. It's sometimes abbreviated CK. CPK testing is often used to evaluate chest pain.
What is the definition of Cp and Cpk in Statistical process control?
Cp is the capability of a process and Cpk is the actual capability of a part running in the process. The only way Cp = Cpk is if the process mean is exactly centered which is seldom the case in manufacturing. Therefore, Cp > or = to Cpk.
What color is the tube for CPK isoenzymes?
The tube for CPK (creatine phosphokinase) isoenzymes is typically red or gold, depending on the laboratory.
What is CPK chemistry blood test?
CPK is an enzyme called creatine kinase. It is mostly found in the heart, brain and muscle tissues. When there is trauma or damage to those tissues the enzyme is released into the bloodstream where it shows up as an elevated CPK on bloodwork. CPK is often elevated after a heavy workout or any type of crushing injury. The CPK is often elevated soon after a heart attack. Some muscle degenerating diseases also can be detected by a constantly high CPK level. It is up to your physician to determine the significance of the result. CPK can further be broken down into specific sub-enzymes called iso-enzymes. One is heart specific, one is muscle specific and so on. So if a CPK level is elevated and the cause is not known, testing for iso-enzymes can indicate what body tissue the CPK is coming from.
What is the market cap for Chesapeake Utilities Corporation CPK?
As of July 2014, the market cap for Chesapeake Utilities Corporation (CPK) is $663,357,115.20.
What happens if your cpk level is high?
A high creatine phosphokinase (CPK) level can indicate muscle damage or stress, as CPK is an enzyme released into the bloodstream when muscle tissue is injured. Elevated CPK levels may suggest conditions like heart attacks, muscle diseases, or strenuous exercise. It's important to consult a healthcare professional for further evaluation and diagnosis, as the underlying cause of elevated CPK needs to be identified and addressed.
What causes cpk level?
When the total CPK level is very high, it usually 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.
Does pericarditis cause high cpk?
Pericarditis itself typically does not cause elevated creatine phosphokinase (CPK) levels. CPK is primarily associated with muscle damage, and while pericarditis may cause chest pain and inflammation, it is not directly linked to muscle injury. However, if there is concurrent myocardial involvement, such as in myopericarditis, CPK levels may rise due to heart muscle damage. It's important to evaluate CPK levels in the context of other clinical findings.
What color tube for CPK?
Creatine phosphokinase (CPK) is typically collected in a red-top tube for serum or a green-top tube for plasma.
What causes elevated CPK level?
When the total CPK level is very high, it usually 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.
