Process planning for a mechanical part involves preparation of a plan that outlines the processing route, operations, machine tools, and so on. Efforts have been made to automate this task. The extraction of relevant part information from the CAD model has been one of the major issues in the automation of process planning. In this paper the process-planning task is decomposed into eight phases. For each phase, problems and suitable solution approaches are discussed. Most process-planning problems are solved using a knowledge-based approach or a combination of optimization and knowledge-based approaches. The concepts presented are illustrated with examples.