The main problem of creating computer-aided design systems (CAD) for press-forging processes is associated with a weak formalization of the subject area. An effective way for solving this problem is to provide the corresponding CAD with expert system properties when weakly structured knowledge is formalized in a certain way and transferred to the knowledge base. The paper describes the concept of developing a production knowledge base model of the computer-aided design system for solids of revolution press-forging. Some specific technological problems are examples of this model application in relation to tasks with point and interval solutions. The proposed concept of developing the knowledge base allows us to more formalize the subject area under consideration, to develop genetic algorithms for solving weakly structured problems of computer-aided forging process design, to ensure the work of appropriate programs without their adjustment to changing production conditions, and it can be used in other subject areas.