Use SPC analysis chart to understand and solve the deviation in production process.
And control or even eliminate these changes.
SPC is generally understood as that CPK we often say includes X bar graph and R graph, but actually SPC.
It also contains many other analysis tools, such as IMR diagram, GRR, P diagram, box imprinting and so on.
But the most basic steps to do these analyses are: first, to ensure that the measurement system is effective and credible, so GRR；; The above mentioned will be used; Then, define the sample size and group spacing of the data to be collected; Third, collect data according to the defined sample size and interval. If it is an X bar chart and an R chart, about 25 sets of data are needed-of course, this is only the general situation; Finally, you can draw a conclusion by analyzing the data you collected by software;