Process Stability and Capability
Process Stability - refers to the consistency of the process to stay within the Control Limits. If the process distribution remains consistent over time, i.e. the outputs fall within the range (Process Width), then the process is said to be stable or in control. If the Outputs are spread across outside the limits, then the process is Unstable or Out of Control.
Process Capability - is a measure of the ability of the process to meet customer specifications. The measure tells how good each individual output is. An estimation of the ppm (defective parts per million) is a method to measure process capability. Capability analysis uses measures like Cp, Cpk, Pp, Ppk to determine the process capability.
An application oriented question on the topic along with responses can be seen below. The best answer was provided by Arunesh Ramalingam on 12th October 2017.