It is demonstrated that, with correct strategy, casting CAD can be built-in into an available casting design system. Several approaches are stated and advised for metallurgical process control systems at mechanical engineering plants. Two general conditions should be met for the CAD introduction to be cheap and without serious consequences. It must be continuous and by stages. Computer-based casting modelling was chosen as the first step. A process control system, a drafting system, a data set repository and text generation system are elements of the second stage.