Research On The NC Programming Of Aircraft Structural Parts

NC programming based on Model Based Definition (MBD) and Feature is thetendencies of NC programming technology, and it is also the key point in integratingCAD/CAPP/CAM. Considering the characteristics of aircraft structural parts, rapid NCprogramming technique is researched to generate NC program rapidly. The mainresearch contents are as follows:1) Build aircraft structural parts MBD model. By analyzing the composition andstructure of MBD model data sets, a solution to generate MBD process model rapidly isproposed, and a MBD process model is established.2) Summarized the structure characteristics of aircraft structural parts features, themachining features are divided into four categories in a new way: simple features,complex features, simple interacting features and complex interacting features. Then amethod for the maximal machining feature recognition based on volume decompositionis proposed. Firstly, the delta-volume is stratified at the machining direction. Secondly,the partition surfaces are generated by retrieving the concave edges of complexinteracting features, which are decomposed into simple features and complex featuresaccording to the split sequence. Finally, the maximal machining features are achievedby merging all the features according to the combination rules.3) Studying the NC process planning method of machining features of aircraftstructural parts, and proposing the method to generate process of machining featuresand element within groove features. Getting the process of maximum machiningfeatures, and plus the features in a process to the rough model in order to generate MBDprocess rough models. Furthermore, the template of machining element information isformulated to extract relevant geometric and non-geometric information, as the basis forhigh-speed machining process planning.4) Researching on the tool path planning of aircraft structural parts’ groove featuresand rib features under High-speed milling environment. Analyzed the processingsolution of groove features and the machining approach of corners, and made tool pathplanning for a variety of groove features. By analyzing two kinds of commonly usedtool path generation methods and mechanism of machining allowance’s generation, Relational equation between scallop height and tool diameter, tool corner radius, cuttingparameters and so on is obtained to guide the tool selection and the set of cuttingparameters. By comparison of several processing methods, the optimal processingmethod of the rib feature is obtained.5) Based on the research above, a NC programming system include featurerecognition module, process planning module and NC programming and machiningsimulation module on CATIA V5is developed for aircraft structural parts. Processplanning module make process by Non-geometric information provided by MBD partmodel and geometry information provided by feature recognition module, then the NCprogramming and machining simulation module will generate and verify the tool path,and feedback the information of machining simulation.