3D-CAPP Feature Identification And Extraction Based On NX Platform

Feature identification and extraction is the core module of three-dimensional CAPP. It concerns the automation and intelligence degree of a 3D-CAPP system. With the development of 3D-CAPP, the feature identification and extraction technology progresses towards many directions at different and levels. In this thesis, the method and framework of feature identification and extraction based on 3D-CAPP are constructed based on NX platform.Taking parts as feature identification and extraction objects, an integrated part information model is constructed based on features. Feature technologies are studied, such as feature definition, feature classification, feature relationship, and object-oriented feature description.Taking housing parts as research objects, their typical processing technologies and methods are analyzed and their processing characteristics are generalized. A feature identification and extraction module for housing parts is developed using the NX secondary development interface. The aim is to get part manufacturing information automatically and then output all manufacturing information in XML format for other CAD/CAM programs.The main contents are as follows.1) The various methods and principles of feature modeling are analyzed and then the relationship between features are analyzed and summarized.2) The processing manufacture features of housing parts are classified to reflect machining types. Thus, it can facilitate the establishment of process databases.3) Using the object-oriented approach, according to three-dimensional data characteristics, the feature model is described. The elements and relations of the feature model are studies.4) The feature-based model identification and extraction system is developed using NX/OPEN and synchronous technology.5) The differences of data structure between non-feature model and feature-based model are analyzed and the approach to feature identification and extraction from the non-feature model is presented.The information integration between CAPP system and CAD system is explored and practiced based on the above research and development.