One challenge in manufacturing-integrated product development is the accessibility of the required manufacturing knowledge. Here, ontologies offer the possibility to structure and formalize information in the form of a knowledge base in order to act as a generic interface to the manufacturing and design specific systems. This paper describes the development of a generic knowledge base called MARON (MAnufacturing Restriction ONtology) for the structured representation of manufacturing restrictions via formalized manufacturing capabilities. Using the example of an expert system for process element-oriented manufacturability analysis, it is shown how MARON contributes to automated decision support in the context of manufacturing-oriented design.