The overarching term process capability is used to describe the current as well as the future expected performance of a process.
A distinction is made between short-term capability (machine capability) and long-term capability (in a limited sense - process capability).
Purpose and benefits You can use this to determine whether a process is suitable for the requirements. For this, a tolerance specification is necessary, which specifies the scope of an allowed deviation from the target value.
The key figure of the process capability Cpk relates the tolerance to the spread of the process. If the process capability is not achieved, then either the spread has to be reduced or the tolerance limits have to be extended. To do this, it is necessary to know the possible limits of a desired function, from when a malfunction can occur