Question: What Is CP CPK?

What is a good CP CPK value?

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.

This tells us nothing about if the process is stable or not..

What is CP and CPK in Six Sigma?

In a process qualified as a Six Sigma process (i.e., one that allows plus or minus six standard deviations within the specifications limits), the Cp is greater than or equal to 2.0. … The process capability index, or Cpk, measures a process’s ability to create product within specification limits.

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.

Can CP CPK be negative?

Both Cpk and Ppk can be a negative numbers. It means that, on average, the process is not meeting customer requirements.

What does CP and CPK stand for?

process capability indicesCp 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 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 does 6 Sigma mean?

Six Sigma is a quality-control methodology developed in 1986 by Motorola, Inc. The method uses a data-driven review to limit mistakes or defects in a corporate or business process. … Six Sigma points to the fact that, mathematically, it would take a six-standard-deviation event from the mean for an error to happen.

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 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)