Modeling of part information for process planning

This paper puts forward a kind of part information model that faces the open CAPP system. The model is hierarchical. Each tier of the model supports certain process planning. The tiers are relatively independent making the model flexible in part information expression. The paper gives the definitions of features and the relations between the features, and emphatically describes the reasoning method in process planning based on partial parts information. The selection of manufacturing process based on features and the operation sequencing methods based on the topology relation of features are also described. The hierarchical part information model and the process plan reasoning method based on constrains submitted in this paper will impact the development of intelligent and practical CAPP system, and also have important value to CAD/CAPP/CAM information integration.