What Is PP And PPK Value?

How do you calculate PP and PPK?

Pp, Ppk In Relation to Z Scores Ppk can be determined by diving the Z score by three.

A z score is the same as a standard score; the number of standard deviations above the mean.

Z = x – mean of the population / standard deviation..

What is the CPK for 3 sigma?

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

What does 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 a good PPK?

The larger the Ppk, the less the variation between process output and specifications. If Ppk is between 0 and 1.0, not all process output meets specifications. If the system is centered on its target value, Ppk should be used in conjunction with the Pp index.

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 PP in statistics?

Statistics – Process Capability (Cp) & Process Performance (Pp)

Why is PPK higher than CPK?

The automotive confusion aside, Ppk will always be greater than Cpk since Ppk is long term capabliity and Cpk is short term capability. The only way that Cpk will be greater than Ppk (other than a misuse of the terms and formulas) is under the conditions stated in a previous post.

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 CPK 1.67 mean?

Excellent, CapableThe 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 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.

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.

What is PP and PPK?

Pp and Ppk It measures how well the data might fit between the spec limits (USL, LSL). It doesn’t care if the process is centered within the limits only if it would fit if it was centered. Ppk is the performance centering index. It measures how well the data is centered between the spec limits.

What does PPK of 1.33 mean?

meeting customer requirementsPpk < 1.33. The process is substandard for meeting customer. requirements. Process improvements must be given high.

What percentage is 4 sigma?

This is where you need to put your thinking caps on because 5-sigma doesn’t mean there’s a 1 in 3.5 million chance that the Higgs boson is real or not….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

What is CP and CPK?

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 is PP unit?

A percentage point or percent point is the unit for the arithmetic difference of two percentages. … In the literature, the percentage point unit is usually either written out, or abbreviated as pp or p.p. to avoid ambiguity. After the first occurrence, some writers abbreviate by using just “point” or “points”.

What is min in CPK formula?

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.

Should I use CPK or PPK?

Another way to look at the difference is that Cpk is used for a subgroup of data, while Ppk is used for the whole process. Cpk is typically used while processing in the ideal conditions to identify if the process is capable of meeting the specifications.

Are CPK and PPK the same?

If we look at the formulas for Cpk and Ppk for normal (distribution) process capability, we can see they are nearly identical: The only difference lies in the denominator for the Upper and Lower statistics: Cpk is calculated using the WITHIN standard deviation, while Ppk uses the OVERALL standard deviation.

What does PPK stand for?

PPKAcronymDefinitionPPKPunt, Pass, and Kick (NFL youth program)PPKProfessional Protection KitPPKPalm Portable KeyboardPPKPublic Private Key16 more rows

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.