Milling Feature Recognition and Construction for Structural Parts Based on STEP

Based on the analysis of the geometry and machining characteristics of aircraft structural parts, and the feature geometry is described with a hierarchical structure. A machining feature recognition method based on neutral file is presented. Firstly, geometry and topology information of CAD model in UG software is obtained from STEP AP203 interface. Secondly, features are extracted from B-rep representation of the part, and then the features, as well as corresponding geometry and topology are mapped machining feature which is utilized as standard interface for CAM. Based on these studies, a feature recognition system was developed in visual C++, which discussed the data mapping methods from AP203 to C++ system, from AP203 to ORACLE sever. The lexical analysis process of the AP203 files, the establishment and operation process of the machining feature database was developed. And the feasibility was verified by an example of structural part.