RECOGNITION OF INTERACTING ROTATIONAL AND PRISMATIC MACHINING FEATURES FROM 3-D MILL-TURN PARTS

Current feature recognition methods generally recognize and classify m achining features into two classes: rotational features and prismatic features. Based on the different characteristics of geometric shapes a nd machining methods, rotational features and prismatic features are r ecognized using different methods. Typically, rotational features are recognized using two-dimensional (2-D) edge and profile patterns. Pris matic features are recognized using 3-D geometric characteristics, for example, patterns in solid models such as 3-D face adjacency relation ships. However, the current existing feature recognition methods canno t be applied directly to a class of so-called mill-turn parts where in teractions between rotational and prismatic features exist. This paper extends the feature recognition domain to include this class of parts with interacting rotational and prismatic features. a new approach, c alled the machining volume generation method, is developed. The featur e volumes are generated by sweeping boundary faces along a direction d etermined by the type of machining operation. Different types of machi ning features can be recognized by generating different forms of machi ning Volumes using various machining operations. The generated machini ng volumes are then classified using face adjacency relationships of t he bounding faces. The algorithms are executed in four steps, classifi cation of faces, determining machining zones, generation of rotational machining volumes and prismatic machining volumes, and classification of features. The algorithms are implemented using the 3-D boundary re presentation data modelled on the ACIS solid modeller. Example parts a re used to demonstrate the developed feature recognition method.