The purpose of the control chart

One of the purposes of using the control chart is to analyze and judge whether there is any abnormality in the production process by observing the distribution of product quality characteristic values on the control chart. Once the abnormality is found, necessary measures should be taken to eliminate it in time to restore the production process to a stable state. Control chart can also be used to make the production process reach the state of statistical control. The distribution of product quality characteristic value is a statistical distribution. Therefore, it is necessary to apply the relevant theories and knowledge of probability theory to draw the control chart.