The article presents a comprehensive example that demonstrates the control of a plastic injection process in practice. The demonstrated example is from an unnamed company and the data had to be adjusted by a coefficient. It includes measurement and analysis of the production process, its control using a control diagram to bring the production process to a state under statistical control by applying tests of non-random clusters and subsequent evaluation of process capability. The paper shows a histogram and control charts from the measured values that were obtained from the production process at the time. The last part of the article gives an example of the maintenance of economical statistical optimization for four scenarios. Here, the costs that the company incurs in maintaining the machinery are taken into account. The data in the example was again modified by the author so that the company was not easily traceable.