Development of a feature recognition module for tapered and curved base features

This paper presents a feature recognition module which uses the B-rep details extracted from the STandard for Exchange of Product (STEP) format to recognize the manufacturing features on a prismatic part. It adopts the syntactic pattern recognition technique to recognize five classes of features considered in this research by matching the standard pattern strings developed for every class of feature. Using these strings, initially, the types of faces on the prismatic part are determined and edge loops are constructed. The edge loops describe a feature by the information implicit in the details of the edges, vertices, coordinate points, and directions. Using the edge loops and by checking the presence of similar edge loops on parallel faces and the connectivity of faces between parallel edge loops, the final shape of a feature is identified. The developed methodology identifies interacting, tapering, interacting-tapering, curved base features, and tapering cross-sections. Methodologies are presented here to calculate the full dimensional details of all of the features. A case study dealing with complex geometries is presented in the validation of the proposed feature recognizer.