What's Statistical Process Control (SPC)
Statistical Process Control (SPC) is an effective method of monitoring a process through the use of control charts. Much of its power of Statistical Process Control (SPC) lies in the ability to monitor both process center and the variation about that center.
By collecting data from samples at various points within the process, variations in the process that may affect the quality of the end product or service can be detected and corrected, thus reducing waste as well as the likelihood that problems will be passed on to the customer. Statistical Process Control (SPC) has an emphasis on early detection and prevention of problems.
Below is an example to illustrate statistical process control.
A thermostat is a simple example for a closed control loop. It constantly measures the current temperature, and controls the heater's valve setting to increase or decrease the room temperature according to the user-defined setting. A simple method switches the heater either completely on, or completely off, and an overshoot and undershoot of the controlled temperature must be expected. A more expensive method varies the amount of heat provided by the heater depending on the difference between the required temperature (the "setpoint") and the actual temperature. This minimizes over/undershoot.
