Geometrical reasoning based on attributed graph grammar for prismatic parts

Modern manufacturing systems rely on a smooth and quick transformation of the design specification into manufacturing instructions. The shift towards feature-based design and manufacturing supports this effort. One of the weak links in this chain of activities is the conversion of the design features into the manufacturing features. This article presents a method based on graph grammar parsing that converts design geometrical features into manufacturing geometrical features. These features can then be used in process planning activities. The method presented extends the state of the art of syntactic graph-based features recognition by supporting embedding transformations, attribute transfer algorithms, decomposition of overlapping features and removal of empty volumes. In addition, the analysis provided by the graph parsing algorithms implicitly treats the features as solid models without the need to perform complicated geometrical analysis. The system was implemented for prismatic components such that they can be produced on a triple axis vertical milling machine, and currently contains 20 rules.