Extracting the turning volume and features for a mill/turn part with multiple extreme faces

Abstract

This paper presents a geometric reasoning approach for extracting the maximum turnable state (MTS) and its turning features for a mill/turn part which has multiple extreme faces. Here, an extreme face refers to a vertical planar face whose adjacent faces are all located on the same side of the plane. It is more difficult to construct the MTS for such a part because the positions of its cross-sectional planes do not change monotonically on the principal axis, and the concave regions formed by its profile need special treatments in its feature recognition. The proposed method addresses the issue of multiple extreme faces with a graph decomposition strategy for the attributed adjacency graph of CAD models, and handles the feature recognition problem by matching the feature shape descriptors with the descriptors of local element combinations out of the delta volume mesh. The method not only produces all the turning features for a part but also generates the feature precedence graph as well from reasoning on their adjacency relations. At the end of the paper, an example is presented to demonstrate the method’s effectiveness.