SPC means Statistical Process Control and is a method to improve quality within a production process. Quality losses in a production process have a very high cost, because these products need to be reworked, thrown out of the process; or in the worst case, they reach the client damaging the organization's image and profits.

In order to become a defectuous product, it needs to not fulfil a quality variable. SPC is based on the measurement of these variables that indicate a product's quality, not only at the end, when it is too late, but periodically, during the production process, in order to know if the process is controlled within control limits and within limits specified by the client (in edinn® M2 indicated in green and red colour).

CPK is a ratio that indicates if the process is centred related to control limits and client specifications. Mathematically, SPC methodology is very complex. You need to consult bibliography (see below) if you want to know the exact formulas associated to SPC. edinn® M2 contains all SPC formulas and makes all calculations so the user does not have to do this. In one of the SPC reports it is possible to obtain automatically and in real time the main ratios (like CPK). Following edinn® M2´s philosophy, making SPC calculations with the system is very easy. Periodically, edinn® M2 will measure quality variables or will ask the operator to do so by making blink the SPC button. If it does not receive SPC data, a justification is asked for why they are not taking data. Based on SPC data, automatically and in real time, a control graphic and histogram are generated.

For those values out of control limits, the operator is asked to justify the steps he followed to "retake" the process. The SPC graphic is interactive, in order to let the user click on each point and see when measurements were taken, what justification was given, etc.

For more information please see the external links:

• Statistical Process Control
• CPK