Research On NC Automatic Programming System Of Typical Aeroengine Parts Based On Feature Recognition

Aeroengine is called the "heart" of an aircraft.The quality and efficiency of its manufacture often determine the performance of the aircraft,as well as the development cycle and cost of the aircraft.With the improvement of aeroengine performance requirements and the wide application of numerical control machining technology in the aviation field,aeroengine parts are gradually developing in performance and high precision.The traditional NC machining programming method has become the main factors restricting the development of aeroengine parts,with heavy workload,low efficiency,unstable quality and strong experience dependence.For this reason,this thesis puts forward a kind of NC automatic programming method for typical parts of aeroengine based on machining feature recognition,establishes a fast programming mechanism from machining feature recognition,NC automatic programming,cutting parameter automatic optimization to creating process file,and based on UG secondary development technology,taking the compressor impeller and combustion chamber case of aeroengine as example for the NC automatic programming prototype system.The results of VERICUT NC simulation and application show that the prototype system realizes the automation and standardization of NC programming,and effectively improves the efficiency and quality of NC programming of aeroengine parts.The main contents of this paper are as follows:(1)A method of automatic recognition and extraction of machining features is proposed.The graph structure of the computer is applied to the method of machining feature recognition.Firstly,the topological information and geometric information of the 3D model of the part are extracted,and the attribute adjacency graph is established.Then,the attribute adjacency graph is decomposed into several feature subgraphs by the method of graph decomposition,and the graph is matched with the features in the predefined feature library to complete the feature recognition.(2)A feature-based NC automatic programming method is proposed.Under the platform of UG/CAM,according to the result of machining feature recognition,the method of parametric modeling is used to complete the automatic creation of machining blank,and the database technology is used to establish the machining rule library,tool library and cutting parameter library;the automatic programming of NC machining is realized.(3)The cutting parameter is optimized based on genetic algorithm.The multi-objective optimization mathematical model is established with the spindle speed and feed speed of machine tool as the optimization variables.The optimization results are solved by genetic algorithm,and stored in the cutting parameter database for the programming module to call automatically.Finally,the superiority of the cutting parameter optimization module is verified by the optimization example.(4)The prototype system is developed and verified by an example.Based on UG NX10 and visual studio 12,a prototype system of NC automatic programming for aeroengine compressor impeller and combustor case is developed by using UG secondary development technology.The practicability of the prototype system is verified by VERICUT NC simulation results.(5)Summarize the full thesis,and further analyze the advancement of the methods proposed in thesis,and look forward to the future research work.