| The ultimate goal of automated process planning is to be able to generate a complete process plan automatically starting from a CAD description of the part. 3-D CAD systems provide both the geometric and topological information required to describe the part. Current generation of process planning systems require human input to analyze the part geometry and restructure the part definition into a form suitable for process planning. This research focuses on developing methods to analyze a part description from a solid modeler, making inferences by reasoning geometrically, and extracting information to drive a process planning system. Some issues considered are machined surface detection, recognition of features, and analysis of features to determine tool approach directions and precedence relationship between features. Using a Boundary representation to describe a solid part, algorithms have been developed to extract the required information. The concept of Attributed Adjacency Graph has been developed for the recognition of polyhedral features (slots, pockets, blind slots, steps, etc). Cylindrical holes are recognized separately. The recognition algorithm has the capability to recognize several classes of interacting features. The features after recognition are analyzed for feasible tool approach directions based on global as well as local considerations. The precedence constraints for machining the features are obtained based on the relationship between the features. This research can also be viewed as an aspect of the more general problem of machine understanding of parts for manufacturing applications. |
