What does it mean if a process has a Cpk of 2?

A process with a Cpk of 2 indicates that the process is highly capable. Cpk, or process capability index, measures how well a given process is performing relative to its specification limits. When the Cpk value is 2, it signifies that the process's spread (or variability) is only a quarter of the distance between the upper and lower specification limits. This means the process not only meets the specifications but does so with a significant margin, reflecting low variability and a high degree of consistency.

In practical terms, a Cpk value of 2 suggests that the process is operating very effectively, producing products that are consistently within tolerance and demonstrating high performance levels. Such a process is considered robust, and it shows that improvements in quality and efficiency have likely been achieved through effective process control and optimization techniques. A Cpk of 2 is a strong indicator of a well-managed process capable of producing quality outputs with minimal defects.