4 ms·
In my experience in manufacturing, SPC control charts are used to assess / analyze / monitor control, ie, quantify the degree to which a process is in control..
by michaericalribo 6y ago
In my experience in manufacturing, SPC control charts are used to assess / analyze / monitor control, ie, quantify the degree to which a process is in control...but not often to actually manage / maintain that control. As another commenter alluded to, the vast majority of control systems are managed by PID loops, and SPC is a complement to those systems, not a replacement per se.
- kqr 6y agoThat is indeed how things are traditionally done. I (along with Wheeler) am suggesting that division does not necessarily have to exist, and the control charts themselves can serve as useful feedback mechanisms. In many cases they may even be more effective than a PID controller, with zero tuning required. As Wheeler notes in his article, PID controllers are based on the assumption that calibration/adjustments are free. As any practitioner of SPC knows, adjustments are never actually free in the face of natural variation in the process.