The National Institute of Standards and Technology (NIST) Design and Process Planning Integration (DPPI) project is developing an open, neutral manufacturing process object model to enable software interoperability among preliminary product design, process planning, and manufacturing execution. This object model has been used as the basis for developing the ISO 16100 standard: Industrial automation systems & integration—Manufacturing software capability profiling, Part 2: Information models for interoperability. This paper describes an object-oriented manufacturing process information model in the Unified Modeling Language. The model comprises classes on the necessary manufacturing information, such as artifact, manufacturing activities, workpiece, manufacturing equipment, estimated cost and time, and manufacturing process sequences. Major manufacturing activities include setup, workpiece handling, loading/unloading, and processing. This model is capable of describing the hierarchical structure of the information representing manufacturing processes of an artifact by means of recursive definition. Also, the model includes the representation of concurrent activities, alternative activities, and parallel activities. Furthermore, this model provides software developers with the information foundation for developing new process planning systems such that software development time can be significantly reduced.