Research Of Hybrid Feature Recognition Method And Application In The Blank Design

With the gradual development of the level of information and automation, seamless integration of CAD, CAM and CAPP systems has been urgently demanded by manufacturing industries. Automatic feature recognition technology, which connects geometry topology information of parts to special engineering information, is an ideal intelligent interface between CAD and CAPP, and converts design models of part into manufacturing models.Many automatic feature recognition methods have been proposed, but the effect is still to be improved. Therefore, this thesis presents a method of hybrid feature recognition based on graph:splits merged faces by creating split lines in order to separate intersecting feature, classifies isolated features, and recognizes features by using rules. The converse process from design models to blank models is a prerequisite for process planning, but there are also many unresolved issues in this area. The thesis makes further research on the method of generating blank models based on feature recognition.(1) A new method of separating intersecting features which include merged faces is studied. Since traditional feature recognition method based on graph is difficult to separate intersecting features which include merged faces, this thesis presents a method of splitting merged faces by creating split lines in order to separate this kind of intersecting feature.(2) A new method of recognizing isolated features by using rules is studied. According to boundary pattern of common features, classifies isolated features, extracts recognition knowledge of each kind of feature, which is expressed in the form of the knowledge tree, and recognizes features by using the knowledge tree and reasoning.(3) A new method of the conversion from design models to blank models is studied. Firstly, according to the surface roughness information of part models, determines whether each shape feature is a machining feature. Secondly, evaluates machining features by process knowledge databases. Finally, according to results of the evaluation and the parameters of machining features, offsets automatically machining features in design models.(4) The FRBMS plug-in which is used to verify the above methods is developed With the Access2007database management platform and the compile software VC The FRBMS plug-in on the Solidworks2010geometric platform is developed to verify the automatic feature recognition method and the method of generating blank model.