Mostly interested in understanding how engineers determine if an engineering process is stable and capable, particular in design for manufacturing (DFM) frame work for components. Some example components to consider are:

• Flow rate for Solenoid Valve
• Torque for a Brushless DC Motor
• Capacitance for a Capacitor

Note: There are infinite amount of examples.

How does an engineer confirm if a vendor has a stable and capable process (incoming material)? To be cost competitive it is important to have the least amount (optimal) manufacturing test and inspection processors yet ensure the end product meets specification. How does an engineer ensure the final product meet specification (outgoing material)?