What Does A PPK Of 1.0 Mean?

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 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. … Specifications are normally defined in terms of nominal (+/-) tolerances or ranges (low to high.

How do you determine 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.

How do you calculate process performance?

The process capability is thus, defined as the ratio of the voice of the customer and voice of the process: Cp = (USL-LSL)/6σ.

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 does PPK less than 1 mean?

Low Ppk. In this example, the distance from the process mean to the nearest specification limit (USL) is less than the one-sided process spread. Therefore, Ppk is low (0.66), and the overall capability of the process is poor.

What is an acceptable PPK?

According to Six Sigma philosophy, Cp or Pp and Cpk or Ppk should be greater than 1.50. From a technical standpoint, Six Sigma deems a process being acceptable only after achieving a maximum defect rate of 3.4 parts per million opportunities.

How is PPK calculated?

Process Mean close to USL If your Process Mean (central tendency) is closer to the USL, use: Ppk = [ USL – x(bar) ] / 3 s, where x(bar) is the Process Mean.

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 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?

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

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.

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 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.

What does PPK stand for?

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

What is PP and PPK value?

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 a Cpk of 1.0 mean?

Process Capability IndexDefinition: Cpk = Cpk = Process Capability Index. … 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.