CPK (Process Capability Index)

The Process Capability Index (CPK) measures how well a manufacturing process can produce items within specified limits or tolerances. It compares the spread and centering of the process output to these limits, indicating how capable the process is of consistently meeting quality standards. A higher CPK (closer to or above 1.0) signifies the process reliably produces parts within acceptable ranges, while a lower value suggests frequent deviations. Essentially, CPK helps assess whether a process is capable of maintaining quality and helps identify areas for improvement to ensure consistent, high-quality output.