In the era of Industry 4.0, the automation of processes in the life cycle of a product seems to be a necessity. Although programming CNC machines with CAM systems make it possible, it is necessary to effectively acquire knowledge about the programming process and technological requirements for effective automation. The paper presents a method for decomposition of knowledge about the CNC machine programming process based on acquiring knowledge from various sources, both from technologists as well as on the basis of analysis of archival CNC control programs. To decompose the programming process, it is proposed to apply the knowledge model described by various attributes. Verification of the method is shown in the process of knowledge decomposition for manufacturing special production tooling.