Feature-based NC Programming Technology For Aircraft Panels

Supported by the National S&T Major Project, and considering the demands of aviation enterprises, the technology of feature recognition and tool path generation for aircraft panels are studied so as to meet the requirements of the NC programming of mirror milling for aircraft panels. The main achievements of this paper are presented as follows:1) An industry survey of the NC programming technology and machining equipment of aircraft panels was carried out. Various processing technologies of aircraft panels machining were compared in the survey, which leaded to the conclusion that mirror milling technology is the development trend of machining aircraft panels. The automatic recognition technology of intersecting features and tool path generation technology are the bottlenecks for realizing the automatic NC programming after further researches.2) A recognition method of complex intersecting features of aircraft panels was proposed. The intersecting features of aircraft panels were defined by considering the strong coupling relationship between geometries and processes. Preliminary feature recognition was realized based on adjacency graph. Machining regions were divided by defining the pole of features and then features reconstruction was completed. Eventually, the recognition of complex intersecting features of aircraft panels, which has strong coupling relationship between geometries and processes was realized.3) An automatic tool path generation method based on features for mirror milling technology was proposed. According to the feature recognition results, the drive surfaces of intersecting features were reconstructed by the way of filling, dividing and extending, and the drive edges were reconstructed by B spline fitting. Tool path which satisfied the requirements of the mirror milling equipment was generated automatically after defining the drive geometry properties and residual position analysis based on features.4) The results of the study are applied in the feature based NC programming system for mirror milling equipment, the system has been used for NC programming of several aircraft panels in aviation enterprises.