The process is stable? Process capacity is enough? Is a technical problem or a management problem? SPC can help us, there are mainly two functions to solve these problems.SPC: the is analysis of user problems (this is often forgotten), the recognition process is controlled, the problem can be decomposed for unexpected problems (out of control) or structural problems (controlled process but did not reach the required), to solve the problem provide direction; the second is process monitoring - through the use of appropriate control chart for monitoring the process is controlled, only when the process is out of control take measures to avoid the loss of opportunities for improvement due to the adjustment, to improve and control the quality.